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Posted to commits@tajo.apache.org by hy...@apache.org on 2013/07/02 16:16:34 UTC

[40/51] [partial] TAJO-22: The package prefix should be org.apache.tajo. (DaeMyung Kang via hyunsik)

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/BitArray.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/BitArray.java b/tajo-common/src/main/java/org/apache/tajo/util/BitArray.java
new file mode 100644
index 0000000..0c3bd1b
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/BitArray.java
@@ -0,0 +1,99 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+import java.nio.ByteBuffer;
+
+public class BitArray {
+  private byte [] data;
+  private int length;
+
+  public BitArray(int numBits) {
+    data = new byte[numBits];
+    this.length = numBits;
+  }
+  public BitArray(byte [] bytes) {
+    this.data = bytes;
+    length = bytes.length * 8;
+  }
+
+  public void set(int idx) {
+    int offset;
+    byte dummy;
+
+    if (idx >= length)
+      throw new IllegalArgumentException("length is " + length
+          + ", but a given index is " + idx + ".");
+
+    offset = idx % 8;
+    dummy = 1;
+    dummy <<= 7-offset;
+    data[idx / 8] |= dummy;
+  }
+
+  public boolean get(int idx) {
+    int offset;
+
+    if(idx >= length)
+      throw new IllegalArgumentException("length is " + length
+          + ", but a given index is " + idx + ".");
+
+    offset = idx % 8;
+    return (((data[idx / 8] >>> 7 - offset) & 1) == 1);
+  }
+
+  public void clear() {
+    for (int i = 0; i < data.length; i++) {
+      data[i] = 0;
+    }
+  }
+
+  public int size() {
+    return length;
+  }
+
+  public byte [] toArray() {
+    return data;
+  }
+
+  public void fromByteBuffer(ByteBuffer byteBuffer) {
+    clear();
+    int i = 0;
+    while(byteBuffer.hasRemaining()) {
+      data[i] = byteBuffer.get();
+    }
+  }
+
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+
+    for(int i = 0;i < length;i++) {
+      if(this.get(i))
+        sb.append("1");
+      else
+        sb.append("0");
+
+      if (i > 0 && i % 8 == 0) {
+        sb.append(" ");
+      }
+    }
+
+    return sb.toString();
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/Bytes.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/Bytes.java b/tajo-common/src/main/java/org/apache/tajo/util/Bytes.java
new file mode 100644
index 0000000..64ba1b8
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/Bytes.java
@@ -0,0 +1,1624 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+import com.google.common.annotations.VisibleForTesting;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.io.RawComparator;
+import org.apache.hadoop.io.WritableComparator;
+import org.apache.hadoop.io.WritableUtils;
+import sun.misc.Unsafe;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.lang.reflect.Field;
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Comparator;
+import java.util.Iterator;
+
+/**
+ * Utility class that handles byte arrays, conversions to/from other types,
+ * comparisons, hash code generation, manufacturing keys for HashMaps or
+ * HashSets, etc.
+ */
+public class Bytes {
+
+  private static final Log LOG = LogFactory.getLog(Bytes.class);
+
+  /**
+   * Size of boolean in bytes
+   */
+  public static final int SIZEOF_BOOLEAN = Byte.SIZE / Byte.SIZE;
+
+  /**
+   * Size of byte in bytes
+   */
+  public static final int SIZEOF_BYTE = SIZEOF_BOOLEAN;
+
+  /**
+   * Size of char in bytes
+   */
+  public static final int SIZEOF_CHAR = Character.SIZE / Byte.SIZE;
+
+  /**
+   * Size of double in bytes
+   */
+  public static final int SIZEOF_DOUBLE = Double.SIZE / Byte.SIZE;
+
+  /**
+   * Size of float in bytes
+   */
+  public static final int SIZEOF_FLOAT = Float.SIZE / Byte.SIZE;
+
+  /**
+   * Size of int in bytes
+   */
+  public static final int SIZEOF_INT = Integer.SIZE / Byte.SIZE;
+
+  /**
+   * Size of long in bytes
+   */
+  public static final int SIZEOF_LONG = Long.SIZE / Byte.SIZE;
+
+  /**
+   * Size of short in bytes
+   */
+  public static final int SIZEOF_SHORT = Short.SIZE / Byte.SIZE;
+
+
+  /**
+   * Estimate of size cost to pay beyond payload in jvm for instance of byte [].
+   * Estimate based on study of jhat and jprofiler numbers.
+   */
+  // JHat says BU is 56 bytes.
+  // SizeOf which uses java.lang.instrument says 24 bytes. (3 longs?)
+  public static final int ESTIMATED_HEAP_TAX = 16;
+
+  /**
+   * Byte array comparator class.
+   */
+  public static class ByteArrayComparator implements RawComparator<byte []> {
+    /**
+     * Constructor
+     */
+    public ByteArrayComparator() {
+      super();
+    }
+    public int compare(byte [] left, byte [] right) {
+      return compareTo(left, right);
+    }
+    public int compare(byte [] b1, int s1, int l1, byte [] b2, int s2, int l2) {
+      return LexicographicalComparerHolder.BEST_COMPARER.
+        compareTo(b1, s1, l1, b2, s2, l2);
+    }
+  }
+
+  /**
+   * Pass this to TreeMaps where byte [] are keys.
+   */
+  public static Comparator<byte []> BYTES_COMPARATOR =
+    new ByteArrayComparator();
+
+  /**
+   * Use comparing byte arrays, byte-by-byte
+   */
+  public static RawComparator<byte []> BYTES_RAWCOMPARATOR =
+    new ByteArrayComparator();
+
+  /**
+   * Read byte-array written with a WritableableUtils.vint prefix.
+   * @param in Input to read from.
+   * @return byte array read off <code>in</code>
+   * @throws IOException e
+   */
+  public static byte [] readByteArray(final DataInput in)
+  throws IOException {
+    int len = WritableUtils.readVInt(in);
+    if (len < 0) {
+      throw new NegativeArraySizeException(Integer.toString(len));
+    }
+    byte [] result = new byte[len];
+    in.readFully(result, 0, len);
+    return result;
+  }
+
+  /**
+   * Read byte-array written with a WritableableUtils.vint prefix.
+   * IOException is converted to a RuntimeException.
+   * @param in Input to read from.
+   * @return byte array read off <code>in</code>
+   */
+  public static byte [] readByteArrayThrowsRuntime(final DataInput in) {
+    try {
+      return readByteArray(in);
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  /**
+   * Write byte-array with a WritableableUtils.vint prefix.
+   * @param out output stream to be written to
+   * @param b array to write
+   * @throws IOException e
+   */
+  public static void writeByteArray(final DataOutput out, final byte [] b)
+  throws IOException {
+    if(b == null) {
+      WritableUtils.writeVInt(out, 0);
+    } else {
+      writeByteArray(out, b, 0, b.length);
+    }
+  }
+
+  /**
+   * Write byte-array to out with a vint length prefix.
+   * @param out output stream
+   * @param b array
+   * @param offset offset into array
+   * @param length length past offset
+   * @throws IOException e
+   */
+  public static void writeByteArray(final DataOutput out, final byte [] b,
+      final int offset, final int length)
+  throws IOException {
+    WritableUtils.writeVInt(out, length);
+    out.write(b, offset, length);
+  }
+
+  /**
+   * Write byte-array from src to tgt with a vint length prefix.
+   * @param tgt target array
+   * @param tgtOffset offset into target array
+   * @param src source array
+   * @param srcOffset source offset
+   * @param srcLength source length
+   * @return New offset in src array.
+   */
+  public static int writeByteArray(final byte [] tgt, final int tgtOffset,
+      final byte [] src, final int srcOffset, final int srcLength) {
+    byte [] vint = vintToBytes(srcLength);
+    System.arraycopy(vint, 0, tgt, tgtOffset, vint.length);
+    int offset = tgtOffset + vint.length;
+    System.arraycopy(src, srcOffset, tgt, offset, srcLength);
+    return offset + srcLength;
+  }
+
+  /**
+   * Put bytes at the specified byte array position.
+   * @param tgtBytes the byte array
+   * @param tgtOffset position in the array
+   * @param srcBytes array to write out
+   * @param srcOffset source offset
+   * @param srcLength source length
+   * @return incremented offset
+   */
+  public static int putBytes(byte[] tgtBytes, int tgtOffset, byte[] srcBytes,
+      int srcOffset, int srcLength) {
+    System.arraycopy(srcBytes, srcOffset, tgtBytes, tgtOffset, srcLength);
+    return tgtOffset + srcLength;
+  }
+
+  /**
+   * Write a single byte out to the specified byte array position.
+   * @param bytes the byte array
+   * @param offset position in the array
+   * @param b byte to write out
+   * @return incremented offset
+   */
+  public static int putByte(byte[] bytes, int offset, byte b) {
+    bytes[offset] = b;
+    return offset + 1;
+  }
+
+  /**
+   * Returns a new byte array, copied from the passed ByteBuffer.
+   * @param bb A ByteBuffer
+   * @return the byte array
+   */
+  public static byte[] toBytes(ByteBuffer bb) {
+    int length = bb.limit();
+    byte [] result = new byte[length];
+    System.arraycopy(bb.array(), bb.arrayOffset(), result, 0, length);
+    return result;
+  }
+
+  /**
+   * @param b Presumed UTF-8 encoded byte array.
+   * @return String made from <code>b</code>
+   */
+  public static String toString(final byte [] b) {
+    if (b == null) {
+      return null;
+    }
+    return toString(b, 0, b.length);
+  }
+
+  /**
+   * Joins two byte arrays together using a separator.
+   * @param b1 The first byte array.
+   * @param sep The separator to use.
+   * @param b2 The second byte array.
+   */
+  public static String toString(final byte [] b1,
+                                String sep,
+                                final byte [] b2) {
+    return toString(b1, 0, b1.length) + sep + toString(b2, 0, b2.length);
+  }
+
+  /**
+   * This method will convert utf8 encoded bytes into a string. If
+   * an UnsupportedEncodingException occurs, this method will eat it
+   * and return null instead.
+   *
+   * @param b Presumed UTF-8 encoded byte array.
+   * @param off offset into array
+   * @param len length of utf-8 sequence
+   * @return String made from <code>b</code> or null
+   */
+  public static String toString(final byte [] b, int off, int len) {
+    if (b == null) {
+      return null;
+    }
+    if (len == 0) {
+      return "";
+    }
+    try {
+      return new String(b, off, len, "UTF-8");
+    } catch (UnsupportedEncodingException e) {
+      LOG.error("UTF-8 not supported?", e);
+      return null;
+    }
+  }
+
+  /**
+   * Write a printable representation of a byte array.
+   *
+   * @param b byte array
+   * @return string
+   * @see #toStringBinary(byte[], int, int)
+   */
+  public static String toStringBinary(final byte [] b) {
+    if (b == null)
+      return "null";
+    return toStringBinary(b, 0, b.length);
+  }
+  
+  /**
+   * Converts the given byte buffer, from its array offset to its limit, to
+   * a string. The position and the mark are ignored.
+   *
+   * @param buf a byte buffer
+   * @return a string representation of the buffer's binary contents
+   */
+  public static String toStringBinary(ByteBuffer buf) {
+    if (buf == null)
+      return "null";
+    return toStringBinary(buf.array(), buf.arrayOffset(), buf.limit());
+  }
+
+  /**
+   * Write a printable representation of a byte array. Non-printable
+   * characters are hex escaped in the format \\x%02X, eg:
+   * \x00 \x05 etc
+   *
+   * @param b array to write out
+   * @param off offset to start at
+   * @param len length to write
+   * @return string output
+   */
+  public static String toStringBinary(final byte [] b, int off, int len) {
+    StringBuilder result = new StringBuilder();
+    try {
+      String first = new String(b, off, len, "ISO-8859-1");
+      for (int i = 0; i < first.length() ; ++i ) {
+        int ch = first.charAt(i) & 0xFF;
+        if ( (ch >= '0' && ch <= '9')
+            || (ch >= 'A' && ch <= 'Z')
+            || (ch >= 'a' && ch <= 'z')
+            || " `~!@#$%^&*()-_=+[]{}\\|;:'\",.<>/?".indexOf(ch) >= 0 ) {
+          result.append(first.charAt(i));
+        } else {
+          result.append(String.format("\\x%02X", ch));
+        }
+      }
+    } catch (UnsupportedEncodingException e) {
+      LOG.error("ISO-8859-1 not supported?", e);
+    }
+    return result.toString();
+  }
+
+  private static boolean isHexDigit(char c) {
+    return
+        (c >= 'A' && c <= 'F') ||
+        (c >= '0' && c <= '9');
+  }
+
+  /**
+   * Takes a ASCII digit in the range A-F0-9 and returns
+   * the corresponding integer/ordinal value.
+   * @param ch  The hex digit.
+   * @return The converted hex value as a byte.
+   */
+  public static byte toBinaryFromHex(byte ch) {
+    if ( ch >= 'A' && ch <= 'F' )
+      return (byte) ((byte)10 + (byte) (ch - 'A'));
+    // else
+    return (byte) (ch - '0');
+  }
+
+  public static byte [] toBytesBinary(String in) {
+    // this may be bigger than we need, but lets be safe.
+    byte [] b = new byte[in.length()];
+    int size = 0;
+    for (int i = 0; i < in.length(); ++i) {
+      char ch = in.charAt(i);
+      if (ch == '\\') {
+        // begin hex escape:
+        char next = in.charAt(i+1);
+        if (next != 'x') {
+          // invalid escape sequence, ignore this one.
+          b[size++] = (byte)ch;
+          continue;
+        }
+        // ok, take next 2 hex digits.
+        char hd1 = in.charAt(i+2);
+        char hd2 = in.charAt(i+3);
+
+        // they need to be A-F0-9:
+        if (!isHexDigit(hd1) ||
+            !isHexDigit(hd2)) {
+          // bogus escape code, ignore:
+          continue;
+        }
+        // turn hex ASCII digit -> number
+        byte d = (byte) ((toBinaryFromHex((byte)hd1) << 4) + toBinaryFromHex((byte)hd2));
+
+        b[size++] = d;
+        i += 3; // skip 3
+      } else {
+        b[size++] = (byte) ch;
+      }
+    }
+    // resize:
+    byte [] b2 = new byte[size];
+    System.arraycopy(b, 0, b2, 0, size);
+    return b2;
+  }
+
+  /**
+   * Converts a string to a UTF-8 byte array.
+   * @param s string
+   * @return the byte array
+   */
+  public static byte[] toBytes(String s) {
+    try {
+      return s.getBytes("UTF-8");
+    } catch (UnsupportedEncodingException e) {
+      LOG.error("UTF-8 not supported?", e);
+      return null;
+    }
+  }
+
+  /**
+   * Convert a boolean to a byte array. True becomes -1
+   * and false becomes 0.
+   *
+   * @param b value
+   * @return <code>b</code> encoded in a byte array.
+   */
+  public static byte [] toBytes(final boolean b) {
+    return new byte[] { b ? (byte) -1 : (byte) 0 };
+  }
+
+  /**
+   * Reverses {@link #toBytes(boolean)}
+   * @param b array
+   * @return True or false.
+   */
+  public static boolean toBoolean(final byte [] b) {
+    if (b.length != 1) {
+      throw new IllegalArgumentException("Array has wrong size: " + b.length);
+    }
+    return b[0] != (byte) 0;
+  }
+
+  /**
+   * Convert a long value to a byte array using big-endian.
+   *
+   * @param val value to convert
+   * @return the byte array
+   */
+  public static byte[] toBytes(long val) {
+    byte [] b = new byte[8];
+    for (int i = 7; i > 0; i--) {
+      b[i] = (byte) val;
+      val >>>= 8;
+    }
+    b[0] = (byte) val;
+    return b;
+  }
+
+  /**
+   * Converts a byte array to a long value. Reverses
+   * {@link #toBytes(long)}
+   * @param bytes array
+   * @return the long value
+   */
+  public static long toLong(byte[] bytes) {
+    return toLong(bytes, 0, SIZEOF_LONG);
+  }
+
+  /**
+   * Converts a byte array to a long value. Assumes there will be
+   * {@link #SIZEOF_LONG} bytes available.
+   *
+   * @param bytes bytes
+   * @param offset offset
+   * @return the long value
+   */
+  public static long toLong(byte[] bytes, int offset) {
+    return toLong(bytes, offset, SIZEOF_LONG);
+  }
+
+  /**
+   * Converts a byte array to a long value.
+   *
+   * @param bytes array of bytes
+   * @param offset offset into array
+   * @param length length of data (must be {@link #SIZEOF_LONG})
+   * @return the long value
+   * @throws IllegalArgumentException if length is not {@link #SIZEOF_LONG} or
+   * if there's not enough room in the array at the offset indicated.
+   */
+  public static long toLong(byte[] bytes, int offset, final int length) {
+    if (length != SIZEOF_LONG || offset + length > bytes.length) {
+      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_LONG);
+    }
+    long l = 0;
+    for(int i = offset; i < offset + length; i++) {
+      l <<= 8;
+      l ^= bytes[i] & 0xFF;
+    }
+    return l;
+  }
+
+  private static IllegalArgumentException
+    explainWrongLengthOrOffset(final byte[] bytes,
+                               final int offset,
+                               final int length,
+                               final int expectedLength) {
+    String reason;
+    if (length != expectedLength) {
+      reason = "Wrong length: " + length + ", expected " + expectedLength;
+    } else {
+     reason = "offset (" + offset + ") + length (" + length + ") exceed the"
+        + " capacity of the array: " + bytes.length;
+    }
+    return new IllegalArgumentException(reason);
+  }
+
+  /**
+   * Put a long value out to the specified byte array position.
+   * @param bytes the byte array
+   * @param offset position in the array
+   * @param val long to write out
+   * @return incremented offset
+   * @throws IllegalArgumentException if the byte array given doesn't have
+   * enough room at the offset specified.
+   */
+  public static int putLong(byte[] bytes, int offset, long val) {
+    if (bytes.length - offset < SIZEOF_LONG) {
+      throw new IllegalArgumentException("Not enough room to put a long at"
+          + " offset " + offset + " in a " + bytes.length + " byte array");
+    }
+    for(int i = offset + 7; i > offset; i--) {
+      bytes[i] = (byte) val;
+      val >>>= 8;
+    }
+    bytes[offset] = (byte) val;
+    return offset + SIZEOF_LONG;
+  }
+
+  /**
+   * Presumes float encoded as IEEE 754 floating-point "single format"
+   * @param bytes byte array
+   * @return Float made from passed byte array.
+   */
+  public static float toFloat(byte [] bytes) {
+    return toFloat(bytes, 0);
+  }
+
+  /**
+   * Presumes float encoded as IEEE 754 floating-point "single format"
+   * @param bytes array to convert
+   * @param offset offset into array
+   * @return Float made from passed byte array.
+   */
+  public static float toFloat(byte [] bytes, int offset) {
+    return Float.intBitsToFloat(toInt(bytes, offset, SIZEOF_INT));
+  }
+
+  /**
+   * @param bytes byte array
+   * @param offset offset to write to
+   * @param f float value
+   * @return New offset in <code>bytes</code>
+   */
+  public static int putFloat(byte [] bytes, int offset, float f) {
+    return putInt(bytes, offset, Float.floatToRawIntBits(f));
+  }
+
+  /**
+   * @param f float value
+   * @return the float represented as byte []
+   */
+  public static byte [] toBytes(final float f) {
+    // Encode it as int
+    return Bytes.toBytes(Float.floatToRawIntBits(f));
+  }
+
+  /**
+   * @param bytes byte array
+   * @return Return double made from passed bytes.
+   */
+  public static double toDouble(final byte [] bytes) {
+    return toDouble(bytes, 0);
+  }
+
+  /**
+   * @param bytes byte array
+   * @param offset offset where double is
+   * @return Return double made from passed bytes.
+   */
+  public static double toDouble(final byte [] bytes, final int offset) {
+    return Double.longBitsToDouble(toLong(bytes, offset, SIZEOF_LONG));
+  }
+
+  /**
+   * @param bytes byte array
+   * @param offset offset to write to
+   * @param d value
+   * @return New offset into array <code>bytes</code>
+   */
+  public static int putDouble(byte [] bytes, int offset, double d) {
+    return putLong(bytes, offset, Double.doubleToLongBits(d));
+  }
+
+  /**
+   * Serialize a double as the IEEE 754 double format output. The resultant
+   * array will be 8 bytes long.
+   *
+   * @param d value
+   * @return the double represented as byte []
+   */
+  public static byte [] toBytes(final double d) {
+    // Encode it as a long
+    return Bytes.toBytes(Double.doubleToRawLongBits(d));
+  }
+
+  /**
+   * Convert an int value to a byte array
+   * @param val value
+   * @return the byte array
+   */
+  public static byte[] toBytes(int val) {
+    byte [] b = new byte[4];
+    for(int i = 3; i > 0; i--) {
+      b[i] = (byte) val;
+      val >>>= 8;
+    }
+    b[0] = (byte) val;
+    return b;
+  }
+
+  /**
+   * Converts a byte array to an int value
+   * @param bytes byte array
+   * @return the int value
+   */
+  public static int toInt(byte[] bytes) {
+    return toInt(bytes, 0, SIZEOF_INT);
+  }
+
+  /**
+   * Converts a byte array to an int value
+   * @param bytes byte array
+   * @param offset offset into array
+   * @return the int value
+   */
+  public static int toInt(byte[] bytes, int offset) {
+    return toInt(bytes, offset, SIZEOF_INT);
+  }
+
+  /**
+   * Converts a byte array to an int value
+   * @param bytes byte array
+   * @param offset offset into array
+   * @param length length of int (has to be {@link #SIZEOF_INT})
+   * @return the int value
+   * @throws IllegalArgumentException if length is not {@link #SIZEOF_INT} or
+   * if there's not enough room in the array at the offset indicated.
+   */
+  public static int toInt(byte[] bytes, int offset, final int length) {
+    if (length != SIZEOF_INT || offset + length > bytes.length) {
+      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_INT);
+    }
+    int n = 0;
+    for(int i = offset; i < (offset + length); i++) {
+      n <<= 8;
+      n ^= bytes[i] & 0xFF;
+    }
+    return n;
+  }
+
+  /**
+   * Put an int value out to the specified byte array position.
+   * @param bytes the byte array
+   * @param offset position in the array
+   * @param val int to write out
+   * @return incremented offset
+   * @throws IllegalArgumentException if the byte array given doesn't have
+   * enough room at the offset specified.
+   */
+  public static int putInt(byte[] bytes, int offset, int val) {
+    if (bytes.length - offset < SIZEOF_INT) {
+      throw new IllegalArgumentException("Not enough room to put an int at"
+          + " offset " + offset + " in a " + bytes.length + " byte array");
+    }
+    for(int i= offset + 3; i > offset; i--) {
+      bytes[i] = (byte) val;
+      val >>>= 8;
+    }
+    bytes[offset] = (byte) val;
+    return offset + SIZEOF_INT;
+  }
+
+  /**
+   * Convert a short value to a byte array of {@link #SIZEOF_SHORT} bytes long.
+   * @param val value
+   * @return the byte array
+   */
+  public static byte[] toBytes(short val) {
+    byte[] b = new byte[SIZEOF_SHORT];
+    b[1] = (byte) val;
+    val >>= 8;
+    b[0] = (byte) val;
+    return b;
+  }
+
+  /**
+   * Converts a byte array to a short value
+   * @param bytes byte array
+   * @return the short value
+   */
+  public static short toShort(byte[] bytes) {
+    return toShort(bytes, 0, SIZEOF_SHORT);
+  }
+
+  /**
+   * Converts a byte array to a short value
+   * @param bytes byte array
+   * @param offset offset into array
+   * @return the short value
+   */
+  public static short toShort(byte[] bytes, int offset) {
+    return toShort(bytes, offset, SIZEOF_SHORT);
+  }
+
+  /**
+   * Converts a byte array to a short value
+   * @param bytes byte array
+   * @param offset offset into array
+   * @param length length, has to be {@link #SIZEOF_SHORT}
+   * @return the short value
+   * @throws IllegalArgumentException if length is not {@link #SIZEOF_SHORT}
+   * or if there's not enough room in the array at the offset indicated.
+   */
+  public static short toShort(byte[] bytes, int offset, final int length) {
+    if (length != SIZEOF_SHORT || offset + length > bytes.length) {
+      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_SHORT);
+    }
+    short n = 0;
+    n ^= bytes[offset] & 0xFF;
+    n <<= 8;
+    n ^= bytes[offset+1] & 0xFF;
+    return n;
+  }
+
+  /**
+   * This method will get a sequence of bytes from pos -> limit,
+   * but will restore pos after.
+   * @param buf
+   * @return
+   */
+  public static byte[] getBytes(ByteBuffer buf) {
+    int savedPos = buf.position();
+    byte [] newBytes = new byte[buf.remaining()];
+    buf.get(newBytes);
+    buf.position(savedPos);
+    return newBytes;
+  }
+
+  /**
+   * Put a short value out to the specified byte array position.
+   * @param bytes the byte array
+   * @param offset position in the array
+   * @param val short to write out
+   * @return incremented offset
+   * @throws IllegalArgumentException if the byte array given doesn't have
+   * enough room at the offset specified.
+   */
+  public static int putShort(byte[] bytes, int offset, short val) {
+    if (bytes.length - offset < SIZEOF_SHORT) {
+      throw new IllegalArgumentException("Not enough room to put a short at"
+          + " offset " + offset + " in a " + bytes.length + " byte array");
+    }
+    bytes[offset+1] = (byte) val;
+    val >>= 8;
+    bytes[offset] = (byte) val;
+    return offset + SIZEOF_SHORT;
+  }
+
+  /**
+   * Convert a BigDecimal value to a byte array
+   *
+   * @param val
+   * @return the byte array
+   */
+  public static byte[] toBytes(BigDecimal val) {
+    byte[] valueBytes = val.unscaledValue().toByteArray();
+    byte[] result = new byte[valueBytes.length + SIZEOF_INT];
+    int offset = putInt(result, 0, val.scale());
+    putBytes(result, offset, valueBytes, 0, valueBytes.length);
+    return result;
+  }
+
+
+  /**
+   * Converts a byte array to a BigDecimal
+   *
+   * @param bytes
+   * @return the char value
+   */
+  public static BigDecimal toBigDecimal(byte[] bytes) {
+    return toBigDecimal(bytes, 0, bytes.length);
+  }
+
+  /**
+   * Converts a byte array to a BigDecimal value
+   *
+   * @param bytes
+   * @param offset
+   * @return the char value
+   */
+  public static BigDecimal toBigDecimal(byte[] bytes, int offset) {
+    return toBigDecimal(bytes, offset, bytes.length);
+  }
+
+  /**
+   * Converts a byte array to a BigDecimal value
+   *
+   * @param bytes
+   * @param offset
+   * @param length
+   * @return the char value
+   */
+  public static BigDecimal toBigDecimal(byte[] bytes, int offset, final int length) {
+    if (bytes == null || length < SIZEOF_INT + 1 ||
+      (offset + length > bytes.length)) {
+      return null;
+    }
+
+    int scale = toInt(bytes, 0);
+    byte[] tcBytes = new byte[length - SIZEOF_INT];
+    System.arraycopy(bytes, SIZEOF_INT, tcBytes, 0, length - SIZEOF_INT);
+    return new BigDecimal(new BigInteger(tcBytes), scale);
+  }
+
+  /**
+   * Put a BigDecimal value out to the specified byte array position.
+   *
+   * @param bytes  the byte array
+   * @param offset position in the array
+   * @param val    BigDecimal to write out
+   * @return incremented offset
+   */
+  public static int putBigDecimal(byte[] bytes, int offset, BigDecimal val) {
+    if (bytes == null) {
+      return offset;
+    }
+
+    byte[] valueBytes = val.unscaledValue().toByteArray();
+    byte[] result = new byte[valueBytes.length + SIZEOF_INT];
+    offset = putInt(result, offset, val.scale());
+    return putBytes(result, offset, valueBytes, 0, valueBytes.length);
+  }
+  
+  /**
+   * @param vint Integer to make a vint of.
+   * @return Vint as bytes array.
+   */
+  public static byte [] vintToBytes(final long vint) {
+    long i = vint;
+    int size = WritableUtils.getVIntSize(i);
+    byte [] result = new byte[size];
+    int offset = 0;
+    if (i >= -112 && i <= 127) {
+      result[offset] = (byte) i;
+      return result;
+    }
+
+    int len = -112;
+    if (i < 0) {
+      i ^= -1L; // take one's complement'
+      len = -120;
+    }
+
+    long tmp = i;
+    while (tmp != 0) {
+      tmp = tmp >> 8;
+      len--;
+    }
+
+    result[offset++] = (byte) len;
+
+    len = (len < -120) ? -(len + 120) : -(len + 112);
+
+    for (int idx = len; idx != 0; idx--) {
+      int shiftbits = (idx - 1) * 8;
+      long mask = 0xFFL << shiftbits;
+      result[offset++] = (byte)((i & mask) >> shiftbits);
+    }
+    return result;
+  }
+
+  /**
+   * @param buffer buffer to convert
+   * @return vint bytes as an integer.
+   */
+  public static long bytesToVint(final byte [] buffer) {
+    int offset = 0;
+    byte firstByte = buffer[offset++];
+    int len = WritableUtils.decodeVIntSize(firstByte);
+    if (len == 1) {
+      return firstByte;
+    }
+    long i = 0;
+    for (int idx = 0; idx < len-1; idx++) {
+      byte b = buffer[offset++];
+      i = i << 8;
+      i = i | (b & 0xFF);
+    }
+    return (WritableUtils.isNegativeVInt(firstByte) ? ~i : i);
+  }
+
+  /**
+   * Reads a zero-compressed encoded long from input stream and returns it.
+   * @param buffer Binary array
+   * @param offset Offset into array at which vint begins.
+   * @throws java.io.IOException e
+   * @return deserialized long from stream.
+   */
+  public static long readVLong(final byte [] buffer, final int offset)
+  throws IOException {
+    byte firstByte = buffer[offset];
+    int len = WritableUtils.decodeVIntSize(firstByte);
+    if (len == 1) {
+      return firstByte;
+    }
+    long i = 0;
+    for (int idx = 0; idx < len-1; idx++) {
+      byte b = buffer[offset + 1 + idx];
+      i = i << 8;
+      i = i | (b & 0xFF);
+    }
+    return (WritableUtils.isNegativeVInt(firstByte) ? ~i : i);
+  }
+
+  /**
+   * @param left left operand
+   * @param right right operand
+   * @return 0 if equal, < 0 if left is less than right, etc.
+   */
+  public static int compareTo(final byte [] left, final byte [] right) {
+    return LexicographicalComparerHolder.BEST_COMPARER.
+      compareTo(left, 0, left.length, right, 0, right.length);
+  }
+
+  /**
+   * Lexicographically compare two arrays.
+   *
+   * @param buffer1 left operand
+   * @param buffer2 right operand
+   * @param offset1 Where to start comparing in the left buffer
+   * @param offset2 Where to start comparing in the right buffer
+   * @param length1 How much to compare from the left buffer
+   * @param length2 How much to compare from the right buffer
+   * @return 0 if equal, < 0 if left is less than right, etc.
+   */
+  public static int compareTo(byte[] buffer1, int offset1, int length1,
+      byte[] buffer2, int offset2, int length2) {
+    return LexicographicalComparerHolder.BEST_COMPARER.
+      compareTo(buffer1, offset1, length1, buffer2, offset2, length2);
+  }
+  
+  /**
+   * The number of bytes required to represent a primitive {@code long}
+   * value.
+   */
+  public static final int LONG_BYTES = Long.SIZE / Byte.SIZE;
+ 
+  interface Comparer<T> {
+    abstract public int compareTo(T buffer1, int offset1, int length1,
+        T buffer2, int offset2, int length2);
+  }
+
+  @VisibleForTesting
+  static Comparer<byte[]> lexicographicalComparerJavaImpl() {
+    return LexicographicalComparerHolder.PureJavaComparer.INSTANCE;
+  }
+
+  /**
+   * Provides a lexicographical comparer implementation; either a Java
+   * implementation or a faster implementation based on {@link Unsafe}.
+   *
+   * <p>Uses reflection to gracefully fall back to the Java implementation if
+   * {@code Unsafe} isn't available.
+   */
+  @VisibleForTesting
+  static class LexicographicalComparerHolder {
+    static final String UNSAFE_COMPARER_NAME =
+        LexicographicalComparerHolder.class.getName() + "$UnsafeComparer";
+    
+    static final Comparer<byte[]> BEST_COMPARER = getBestComparer();
+    /**
+     * Returns the Unsafe-using Comparer, or falls back to the pure-Java
+     * implementation if unable to do so.
+     */
+    static Comparer<byte[]> getBestComparer() {
+      try {
+        Class<?> theClass = Class.forName(UNSAFE_COMPARER_NAME);
+
+        // yes, UnsafeComparer does implement Comparer<byte[]>
+        @SuppressWarnings("unchecked")
+        Comparer<byte[]> comparer =
+          (Comparer<byte[]>) theClass.getEnumConstants()[0];
+        return comparer;
+      } catch (Throwable t) { // ensure we really catch *everything*
+        return lexicographicalComparerJavaImpl();
+      }
+    }
+    
+    enum PureJavaComparer implements Comparer<byte[]> {
+      INSTANCE;
+
+      @Override
+      public int compareTo(byte[] buffer1, int offset1, int length1,
+          byte[] buffer2, int offset2, int length2) {
+        // Short circuit equal case
+        if (buffer1 == buffer2 &&
+            offset1 == offset2 &&
+            length1 == length2) {
+          return 0;
+        }
+        // Bring WritableComparator code local
+        int end1 = offset1 + length1;
+        int end2 = offset2 + length2;
+        for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) {
+          int a = (buffer1[i] & 0xff);
+          int b = (buffer2[j] & 0xff);
+          if (a != b) {
+            return a - b;
+          }
+        }
+        return length1 - length2;
+      }
+    }
+
+    @VisibleForTesting
+    enum UnsafeComparer implements Comparer<byte[]> {
+      INSTANCE;
+
+      static final Unsafe theUnsafe;
+
+      /** The offset to the first element in a byte array. */
+      static final int BYTE_ARRAY_BASE_OFFSET;
+
+      static {
+        theUnsafe = (Unsafe) AccessController.doPrivileged(
+            new PrivilegedAction<Object>() {
+              @Override
+              public Object run() {
+                try {
+                  Field f = Unsafe.class.getDeclaredField("theUnsafe");
+                  f.setAccessible(true);
+                  return f.get(null);
+                } catch (NoSuchFieldException e) {
+                  // It doesn't matter what we throw;
+                  // it's swallowed in getBestComparer().
+                  throw new Error();
+                } catch (IllegalAccessException e) {
+                  throw new Error();
+                }
+              }
+            });
+
+        BYTE_ARRAY_BASE_OFFSET = theUnsafe.arrayBaseOffset(byte[].class);
+
+        // sanity check - this should never fail
+        if (theUnsafe.arrayIndexScale(byte[].class) != 1) {
+          throw new AssertionError();
+        }
+      }
+
+      static final boolean littleEndian =
+        ByteOrder.nativeOrder().equals(ByteOrder.LITTLE_ENDIAN);
+
+      /**
+       * Returns true if x1 is less than x2, when both values are treated as
+       * unsigned.
+       */
+      static boolean lessThanUnsigned(long x1, long x2) {
+        return (x1 + Long.MIN_VALUE) < (x2 + Long.MIN_VALUE);
+      }
+
+      /**
+       * Lexicographically compare two arrays.
+       *
+       * @param buffer1 left operand
+       * @param buffer2 right operand
+       * @param offset1 Where to start comparing in the left buffer
+       * @param offset2 Where to start comparing in the right buffer
+       * @param length1 How much to compare from the left buffer
+       * @param length2 How much to compare from the right buffer
+       * @return 0 if equal, < 0 if left is less than right, etc.
+       */
+      @Override
+      public int compareTo(byte[] buffer1, int offset1, int length1,
+          byte[] buffer2, int offset2, int length2) {
+        // Short circuit equal case
+        if (buffer1 == buffer2 &&
+            offset1 == offset2 &&
+            length1 == length2) {
+          return 0;
+        }
+        int minLength = Math.min(length1, length2);
+        int minWords = minLength / LONG_BYTES;
+        int offset1Adj = offset1 + BYTE_ARRAY_BASE_OFFSET;
+        int offset2Adj = offset2 + BYTE_ARRAY_BASE_OFFSET;
+
+        /*
+         * Compare 8 bytes at a time. Benchmarking shows comparing 8 bytes at a
+         * time is no slower than comparing 4 bytes at a time even on 32-bit.
+         * On the other hand, it is substantially faster on 64-bit.
+         */
+        for (int i = 0; i < minWords * LONG_BYTES; i += LONG_BYTES) {
+          long lw = theUnsafe.getLong(buffer1, offset1Adj + (long) i);
+          long rw = theUnsafe.getLong(buffer2, offset2Adj + (long) i);
+          long diff = lw ^ rw;
+
+          if (diff != 0) {
+            if (!littleEndian) {
+              return lessThanUnsigned(lw, rw) ? -1 : 1;
+            }
+
+            // Use binary search
+            int n = 0;
+            int y;
+            int x = (int) diff;
+            if (x == 0) {
+              x = (int) (diff >>> 32);
+              n = 32;
+            }
+
+            y = x << 16;
+            if (y == 0) {
+              n += 16;
+            } else {
+              x = y;
+            }
+
+            y = x << 8;
+            if (y == 0) {
+              n += 8;
+            }
+            return (int) (((lw >>> n) & 0xFFL) - ((rw >>> n) & 0xFFL));
+          }
+        }
+
+        // The epilogue to cover the last (minLength % 8) elements.
+        for (int i = minWords * LONG_BYTES; i < minLength; i++) {
+          int a = (buffer1[offset1 + i] & 0xff);
+          int b = (buffer2[offset2 + i] & 0xff);
+          if (a != b) {
+            return a - b;
+          }
+        }
+        return length1 - length2;
+      }
+    }
+  }
+
+  /**
+   * @param left left operand
+   * @param right right operand
+   * @return True if equal
+   */
+  public static boolean equals(final byte [] left, final byte [] right) {
+    // Could use Arrays.equals?
+    //noinspection SimplifiableConditionalExpression
+    if (left == right) return true;
+    if (left == null || right == null) return false;
+    if (left.length != right.length) return false;
+    if (left.length == 0) return true;
+    
+    // Since we're often comparing adjacent sorted data,
+    // it's usual to have equal arrays except for the very last byte
+    // so check that first
+    if (left[left.length - 1] != right[right.length - 1]) return false;
+
+    return compareTo(left, right) == 0;
+  }
+  
+  public static boolean equals(final byte[] left, int leftOffset, int leftLen,
+                               final byte[] right, int rightOffset, int rightLen) {
+    // short circuit case
+    if (left == right &&
+        leftOffset == rightOffset &&
+        leftLen == rightLen) {
+      return true;
+    }
+    // different lengths fast check
+    if (leftLen != rightLen) {
+      return false;
+    }
+    if (leftLen == 0) {
+      return true;
+    }
+    
+    // Since we're often comparing adjacent sorted data,
+    // it's usual to have equal arrays except for the very last byte
+    // so check that first
+    if (left[leftOffset + leftLen - 1] != right[rightOffset + rightLen - 1]) return false;
+
+    return LexicographicalComparerHolder.BEST_COMPARER.
+      compareTo(left, leftOffset, leftLen, right, rightOffset, rightLen) == 0;
+  }
+  
+
+  /**
+   * Return true if the byte array on the right is a prefix of the byte
+   * array on the left.
+   */
+  public static boolean startsWith(byte[] bytes, byte[] prefix) {
+    return bytes != null && prefix != null &&
+      bytes.length >= prefix.length &&
+      LexicographicalComparerHolder.BEST_COMPARER.
+        compareTo(bytes, 0, prefix.length, prefix, 0, prefix.length) == 0;      
+  }
+
+  /**
+   * @param b bytes to hash
+   * @return Runs {@link WritableComparator#hashBytes(byte[], int)} on the
+   * passed in array.  This method is what {@link org.apache.hadoop.io.Text} and
+   * {@link ImmutableBytesWritable} use calculating hash code.
+   */
+  public static int hashCode(final byte [] b) {
+    return hashCode(b, b.length);
+  }
+
+  /**
+   * @param b value
+   * @param length length of the value
+   * @return Runs {@link WritableComparator#hashBytes(byte[], int)} on the
+   * passed in array.  This method is what {@link org.apache.hadoop.io.Text} and
+   * {@link ImmutableBytesWritable} use calculating hash code.
+   */
+  public static int hashCode(final byte [] b, final int length) {
+    return WritableComparator.hashBytes(b, length);
+  }
+
+  /**
+   * @param b bytes to hash
+   * @return A hash of <code>b</code> as an Integer that can be used as key in
+   * Maps.
+   */
+  public static Integer mapKey(final byte [] b) {
+    return hashCode(b);
+  }
+
+  /**
+   * @param b bytes to hash
+   * @param length length to hash
+   * @return A hash of <code>b</code> as an Integer that can be used as key in
+   * Maps.
+   */
+  public static Integer mapKey(final byte [] b, final int length) {
+    return hashCode(b, length);
+  }
+
+  /**
+   * @param a lower half
+   * @param b upper half
+   * @return New array that has a in lower half and b in upper half.
+   */
+  public static byte [] add(final byte [] a, final byte [] b) {
+    return add(a, b, new byte [0]);
+  }
+
+  /**
+   * @param a first third
+   * @param b second third
+   * @param c third third
+   * @return New array made from a, b and c
+   */
+  public static byte [] add(final byte [] a, final byte [] b, final byte [] c) {
+    byte [] result = new byte[a.length + b.length + c.length];
+    System.arraycopy(a, 0, result, 0, a.length);
+    System.arraycopy(b, 0, result, a.length, b.length);
+    System.arraycopy(c, 0, result, a.length + b.length, c.length);
+    return result;
+  }
+
+  /**
+   * @param a array
+   * @param length amount of bytes to grab
+   * @return First <code>length</code> bytes from <code>a</code>
+   */
+  public static byte [] head(final byte [] a, final int length) {
+    if (a.length < length) {
+      return null;
+    }
+    byte [] result = new byte[length];
+    System.arraycopy(a, 0, result, 0, length);
+    return result;
+  }
+
+  /**
+   * @param a array
+   * @param length amount of bytes to snarf
+   * @return Last <code>length</code> bytes from <code>a</code>
+   */
+  public static byte [] tail(final byte [] a, final int length) {
+    if (a.length < length) {
+      return null;
+    }
+    byte [] result = new byte[length];
+    System.arraycopy(a, a.length - length, result, 0, length);
+    return result;
+  }
+
+  /**
+   * @param a array
+   * @param length new array size
+   * @return Value in <code>a</code> plus <code>length</code> prepended 0 bytes
+   */
+  public static byte [] padHead(final byte [] a, final int length) {
+    byte [] padding = new byte[length];
+    for (int i = 0; i < length; i++) {
+      padding[i] = 0;
+    }
+    return add(padding,a);
+  }
+
+  /**
+   * @param a array
+   * @param length new array size
+   * @return Value in <code>a</code> plus <code>length</code> appended 0 bytes
+   */
+  public static byte [] padTail(final byte [] a, final int length) {
+    byte [] padding = new byte[length];
+    for (int i = 0; i < length; i++) {
+      padding[i] = 0;
+    }
+    return add(a,padding);
+  }
+
+  /**
+   * Split passed range.  Expensive operation relatively.  Uses BigInteger math.
+   * Useful splitting ranges for MapReduce jobs.
+   * @param a Beginning of range
+   * @param b End of range
+   * @param num Number of times to split range.  Pass 1 if you want to split
+   * the range in two; i.e. one split.
+   * @return Array of dividing values
+   */
+  public static byte [][] split(final byte [] a, final byte [] b, final int num) {
+    byte[][] ret = new byte[num+2][];
+    int i = 0;
+    Iterable<byte[]> iter = iterateOnSplits(a, b, num);
+    if (iter == null) return null;
+    for (byte[] elem : iter) {
+      ret[i++] = elem;
+    }
+    return ret;
+  }
+  
+  /**
+   * Iterate over keys within the passed inclusive range.
+   */
+  public static Iterable<byte[]> iterateOnSplits(
+      final byte[] a, final byte[]b, final int num)
+  {  
+    byte [] aPadded;
+    byte [] bPadded;
+    if (a.length < b.length) {
+      aPadded = padTail(a, b.length - a.length);
+      bPadded = b;
+    } else if (b.length < a.length) {
+      aPadded = a;
+      bPadded = padTail(b, a.length - b.length);
+    } else {
+      aPadded = a;
+      bPadded = b;
+    }
+    if (compareTo(aPadded,bPadded) >= 0) {
+      throw new IllegalArgumentException("b <= a");
+    }
+    if (num <= 0) {
+      throw new IllegalArgumentException("num cannot be < 0");
+    }
+    byte [] prependHeader = {1, 0};
+    final BigInteger startBI = new BigInteger(add(prependHeader, aPadded));
+    final BigInteger stopBI = new BigInteger(add(prependHeader, bPadded));
+    final BigInteger diffBI = stopBI.subtract(startBI);
+    final BigInteger splitsBI = BigInteger.valueOf(num + 1);
+    if(diffBI.compareTo(splitsBI) < 0) {
+      return null;
+    }
+    final BigInteger intervalBI;
+    try {
+      intervalBI = diffBI.divide(splitsBI);
+    } catch(Exception e) {
+      LOG.error("Exception caught during division", e);
+      return null;
+    }
+
+    final Iterator<byte[]> iterator = new Iterator<byte[]>() {
+      private int i = -1;
+      
+      @Override
+      public boolean hasNext() {
+        return i < num+1;
+      }
+
+      @Override
+      public byte[] next() {
+        i++;
+        if (i == 0) return a;
+        if (i == num + 1) return b;
+        
+        BigInteger curBI = startBI.add(intervalBI.multiply(BigInteger.valueOf(i)));
+        byte [] padded = curBI.toByteArray();
+        if (padded[1] == 0)
+          padded = tail(padded, padded.length - 2);
+        else
+          padded = tail(padded, padded.length - 1);
+        return padded;
+      }
+
+      @Override
+      public void remove() {
+        throw new UnsupportedOperationException();
+      }
+      
+    };
+    
+    return new Iterable<byte[]>() {
+      @Override
+      public Iterator<byte[]> iterator() {
+        return iterator;
+      }
+    };
+  }
+
+  /**
+   * @param t operands
+   * @return Array of byte arrays made from passed array of Text
+   */
+  public static byte [][] toByteArrays(final String [] t) {
+    byte [][] result = new byte[t.length][];
+    for (int i = 0; i < t.length; i++) {
+      result[i] = Bytes.toBytes(t[i]);
+    }
+    return result;
+  }
+
+  /**
+   * @param column operand
+   * @return A byte array of a byte array where first and only entry is
+   * <code>column</code>
+   */
+  public static byte [][] toByteArrays(final String column) {
+    return toByteArrays(toBytes(column));
+  }
+
+  /**
+   * @param column operand
+   * @return A byte array of a byte array where first and only entry is
+   * <code>column</code>
+   */
+  public static byte [][] toByteArrays(final byte [] column) {
+    byte [][] result = new byte[1][];
+    result[0] = column;
+    return result;
+  }
+
+  /**
+   * Binary search for keys in indexes.
+   *
+   * @param arr array of byte arrays to search for
+   * @param key the key you want to find
+   * @param offset the offset in the key you want to find
+   * @param length the length of the key
+   * @param comparator a comparator to compare.
+   * @return zero-based index of the key, if the key is present in the array.
+   *         Otherwise, a value -(i + 1) such that the key is between arr[i -
+   *         1] and arr[i] non-inclusively, where i is in [0, i], if we define
+   *         arr[-1] = -Inf and arr[N] = Inf for an N-element array. The above
+   *         means that this function can return 2N + 1 different values
+   *         ranging from -(N + 1) to N - 1.
+   */
+  public static int binarySearch(byte [][]arr, byte []key, int offset,
+      int length, RawComparator<byte []> comparator) {
+    int low = 0;
+    int high = arr.length - 1;
+
+    while (low <= high) {
+      int mid = (low+high) >>> 1;
+      // we have to compare in this order, because the comparator order
+      // has special logic when the 'left side' is a special key.
+      int cmp = comparator.compare(key, offset, length,
+          arr[mid], 0, arr[mid].length);
+      // key lives above the midpoint
+      if (cmp > 0)
+        low = mid + 1;
+      // key lives below the midpoint
+      else if (cmp < 0)
+        high = mid - 1;
+      // BAM. how often does this really happen?
+      else
+        return mid;
+    }
+    return - (low+1);
+  }
+
+  /**
+   * Bytewise binary increment/deincrement of long contained in byte array
+   * on given amount.
+   *
+   * @param value - array of bytes containing long (length <= SIZEOF_LONG)
+   * @param amount value will be incremented on (deincremented if negative)
+   * @return array of bytes containing incremented long (length == SIZEOF_LONG)
+   */
+  public static byte [] incrementBytes(byte[] value, long amount)
+  {
+    byte[] val = value;
+    if (val.length < SIZEOF_LONG) {
+      // Hopefully this doesn't happen too often.
+      byte [] newvalue;
+      if (val[0] < 0) {
+        newvalue = new byte[]{-1, -1, -1, -1, -1, -1, -1, -1};
+      } else {
+        newvalue = new byte[SIZEOF_LONG];
+      }
+      System.arraycopy(val, 0, newvalue, newvalue.length - val.length,
+        val.length);
+      val = newvalue;
+    } else if (val.length > SIZEOF_LONG) {
+      throw new IllegalArgumentException("Increment Bytes - value too big: " +
+        val.length);
+    }
+    if(amount == 0) return val;
+    if(val[0] < 0){
+      return binaryIncrementNeg(val, amount);
+    }
+    return binaryIncrementPos(val, amount);
+  }
+
+  /* increment/deincrement for positive value */
+  private static byte [] binaryIncrementPos(byte [] value, long amount) {
+    long amo = amount;
+    int sign = 1;
+    if (amount < 0) {
+      amo = -amount;
+      sign = -1;
+    }
+    for(int i=0;i<value.length;i++) {
+      int cur = ((int)amo % 256) * sign;
+      amo = (amo >> 8);
+      int val = value[value.length-i-1] & 0x0ff;
+      int total = val + cur;
+      if(total > 255) {
+        amo += sign;
+        total %= 256;
+      } else if (total < 0) {
+        amo -= sign;
+      }
+      value[value.length-i-1] = (byte)total;
+      if (amo == 0) return value;
+    }
+    return value;
+  }
+
+  /* increment/deincrement for negative value */
+  private static byte [] binaryIncrementNeg(byte [] value, long amount) {
+    long amo = amount;
+    int sign = 1;
+    if (amount < 0) {
+      amo = -amount;
+      sign = -1;
+    }
+    for(int i=0;i<value.length;i++) {
+      int cur = ((int)amo % 256) * sign;
+      amo = (amo >> 8);
+      int val = ((~value[value.length-i-1]) & 0x0ff) + 1;
+      int total = cur - val;
+      if(total >= 0) {
+        amo += sign;
+      } else if (total < -256) {
+        amo -= sign;
+        total %= 256;
+      }
+      value[value.length-i-1] = (byte)total;
+      if (amo == 0) return value;
+    }
+    return value;
+  }
+
+  /**
+   * Writes a string as a fixed-size field, padded with zeros.
+   */
+  public static void writeStringFixedSize(final DataOutput out, String s,
+      int size) throws IOException {
+    byte[] b = toBytes(s);
+    if (b.length > size) {
+      throw new IOException("Trying to write " + b.length + " bytes (" +
+          toStringBinary(b) + ") into a field of length " + size);
+    }
+
+    out.writeBytes(s);
+    for (int i = 0; i < size - s.length(); ++i)
+      out.writeByte(0);
+  }
+
+  /**
+   * Reads a fixed-size field and interprets it as a string padded with zeros.
+   */
+  public static String readStringFixedSize(final DataInput in, int size) 
+      throws IOException {
+    byte[] b = new byte[size];
+    in.readFully(b);
+    int n = b.length;
+    while (n > 0 && b[n - 1] == 0)
+      --n;
+
+    return toString(b, 0, n);
+  }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/CommonTestingUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/CommonTestingUtil.java b/tajo-common/src/main/java/org/apache/tajo/util/CommonTestingUtil.java
new file mode 100644
index 0000000..7ff1c1f
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/CommonTestingUtil.java
@@ -0,0 +1,57 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+
+import java.io.IOException;
+import java.util.UUID;
+
+public class CommonTestingUtil {
+  /**
+   *
+   * @param dir a local directory to be created
+   * @return  the created path
+   * @throws IOException
+   */
+  public static Path getTestDir(String dir) throws IOException {
+    Path path = new Path(dir);
+    FileSystem fs = FileSystem.getLocal(new Configuration());
+    if(fs.exists(path))
+      fs.delete(path, true);
+
+    fs.mkdirs(path);
+
+    return fs.makeQualified(path);
+  }
+
+  public static Path getTestDir() throws IOException {
+    String randomStr = UUID.randomUUID().toString();
+    Path path = new Path("target/test-data", randomStr);
+    FileSystem fs = FileSystem.getLocal(new Configuration());
+    if(fs.exists(path))
+      fs.delete(path, true);
+
+    fs.mkdirs(path);
+
+    return fs.makeQualified(path);
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/FileUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/FileUtil.java b/tajo-common/src/main/java/org/apache/tajo/util/FileUtil.java
new file mode 100644
index 0000000..194be55
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/FileUtil.java
@@ -0,0 +1,93 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+import com.google.protobuf.Message;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+
+import java.io.*;
+
+public class FileUtil {
+	public static void writeProto(File file, Message proto) throws IOException {
+		FileOutputStream stream = new FileOutputStream(file);
+		stream.write(proto.toByteArray());
+		stream.close();		
+	}
+	public static void writeProto(OutputStream out, Message proto) throws IOException {
+		out.write(proto.toByteArray());
+	}
+	
+	public static void writeProto(FileSystem fs, Path path, Message proto) throws IOException {
+		FSDataOutputStream stream = fs.create(path);
+		stream.write(proto.toByteArray());
+		stream.close();
+	}
+	
+	public static Message loadProto(File file, Message proto) throws IOException {
+		FileInputStream in = new FileInputStream(file);
+		Message.Builder builder = proto.newBuilderForType().mergeFrom(in);		
+		return builder.build();
+	}
+	
+	public static Message loadProto(InputStream in, Message proto) throws IOException {
+		Message.Builder builder = proto.newBuilderForType().mergeFrom(in);
+		return builder.build();
+	}
+	
+	public static Message loadProto(FileSystem fs,
+                                  Path path, Message proto) throws IOException {
+		FSDataInputStream in = new FSDataInputStream(fs.open(path));
+		Message.Builder builder = proto.newBuilderForType().mergeFrom(in);
+		return builder.build();
+	}
+	
+	public static File getFile(String path) {
+		return new File(path);
+	}
+	
+	public static String readTextFile(File file) throws IOException {
+    StringBuilder fileData = new StringBuilder(1000);
+    BufferedReader reader = new BufferedReader(
+            new FileReader(file));
+    char[] buf = new char[1024];
+    int numRead;
+    while((numRead=reader.read(buf)) != -1){
+        String readData = String.valueOf(buf, 0, numRead);
+        fileData.append(readData);
+        buf = new char[1024];
+    }
+    reader.close();
+    return fileData.toString();
+  }
+
+  public static String humanReadableByteCount(long bytes, boolean si) {
+    int unit = si ? 1000 : 1024;
+    if (bytes < unit) return bytes + " B";
+    int exp = (int) (Math.log(bytes) / Math.log(unit));
+    String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp-1) + (si ? "" : "i");
+    return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
+  }
+
+  public static boolean isLocalPath(Path path) {
+    return path.toUri().getScheme().equals("file");
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/JarUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/JarUtil.java b/tajo-common/src/main/java/org/apache/tajo/util/JarUtil.java
new file mode 100644
index 0000000..6b4144c
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/JarUtil.java
@@ -0,0 +1,64 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+import java.io.IOException;
+import java.net.URL;
+import java.net.URLDecoder;
+import java.util.Enumeration;
+
+public class JarUtil {
+  /**
+   * Find a jar that contains a class of the same name, if any.
+   * It will return a jar file, even if that is not the first thing
+   * on the class path that has a class with the same name.
+   *
+   * @param my_class the class to find.
+   * @return a jar file that contains the class, or null.
+   * @throws java.io.IOException
+   */
+  public static String findContainingJar(Class my_class) {
+    ClassLoader loader = my_class.getClassLoader();
+    String class_file = my_class.getName().replaceAll("\\.", "/") + ".class";
+    try {
+      for(Enumeration itr = loader.getResources(class_file);
+          itr.hasMoreElements();) {
+        URL url = (URL) itr.nextElement();
+        if ("jar".equals(url.getProtocol())) {
+          String toReturn = url.getPath();
+          if (toReturn.startsWith("file:")) {
+            toReturn = toReturn.substring("file:".length());
+          }
+          // URLDecoder is a misnamed class, since it actually decodes
+          // x-www-form-urlencoded MIME type rather than actual
+          // URL encoding (which the file path has). Therefore it would
+          // decode +s to ' 's which is incorrect (spaces are actually
+          // either unencoded or encoded as "%20"). Replace +s first, so
+          // that they are kept sacred during the decoding process.
+          toReturn = toReturn.replaceAll("\\+", "%2B");
+          toReturn = URLDecoder.decode(toReturn, "UTF-8");
+          return toReturn.replaceAll("!.*$", "");
+        }
+      }
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+    return null;
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/NumberUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/NumberUtil.java b/tajo-common/src/main/java/org/apache/tajo/util/NumberUtil.java
new file mode 100644
index 0000000..25d5246
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/NumberUtil.java
@@ -0,0 +1,30 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+public class NumberUtil {
+
+	public static long unsigned32(int n) {
+		return n & 0xFFFFFFFFL;
+	}
+	
+	public static int unsigned16(short n) {
+		return n & 0xFFFF;
+	}
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java b/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java
new file mode 100644
index 0000000..410815f
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java
@@ -0,0 +1,39 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+import java.lang.reflect.Constructor;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class ReflectionUtil {
+  private static final Class<?>[] EMPTY_ARRAY = new Class[]{};
+
+  /**
+   * Cache of constructors for each class. Pins the classes so they
+   * can't be garbage collected until ReflectionUtils can be collected.
+   */
+  private static final Map<Class<?>, Constructor<?>> CONSTRUCTOR_CACHE =
+      new ConcurrentHashMap<Class<?>, Constructor<?>>();
+
+	public static Object newInstance(Class<?> clazz) 
+			throws InstantiationException, IllegalAccessException {         
+		return clazz.newInstance();
+	}
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java b/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java
new file mode 100644
index 0000000..33021fe
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java
@@ -0,0 +1,104 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+import org.apache.tajo.QueryIdFactory;
+import org.apache.tajo.QueryUnitAttemptId;
+
+import java.util.*;
+
+/**
+ * It provides miscellaneous and useful util methods.
+ */
+public class TUtil {
+  /**
+   * check two objects as equals. 
+   * It will return true even if they are all null.
+   * 
+   * @param s1
+   * @param s2
+   * @return true if they are equal or all null
+   */
+  public static boolean checkEquals(Object s1, Object s2) {
+    if (s1 == null ^ s2 == null) {
+      return false;
+    } else if (s1 == null && s2 == null) {
+      return true;
+    } else {
+      return s1.equals(s2);
+    }
+  }
+
+  /**
+   * check two arrays as equals. 
+   * It will return true even if they are all null.
+   * 
+   * @param s1
+   * @param s2
+   * @return true if they are equal or all null
+   */
+  public static boolean checkEquals(Object [] s1, Object [] s2) {
+    if (s1 == null ^ s2 == null) {
+      return false;
+    } else if (s1 == null && s2 == null) {
+      return true;
+    } else {
+      return Arrays.equals(s1, s2);
+    }
+  }
+  
+  public static <T> T[] concat(T[] first, T[] second) {
+    T[] result = Arrays.copyOf(first, first.length + second.length);
+    System.arraycopy(second, 0, result, first.length, second.length);
+    return result;
+  }
+
+  public static <T> Set<T> newHashSet() {
+    return new HashSet<T>();
+  }
+
+  public static <T> List<T> newList() {
+    return new ArrayList<T>();
+  }
+
+  public static <T> List<T> newList(T...items) {
+    List<T> list = new ArrayList<T>();
+    for (T t : items) {
+      list.add(t);
+    }
+
+    return list;
+  }
+
+  public static <T> List<T> newList(Collection<T> items) {
+    List<T> list = new ArrayList<T>();
+    for (T t : items) {
+      list.add(t);
+    }
+
+    return list;
+  }
+
+  public  static QueryUnitAttemptId newQueryUnitAttemptId() {
+    return QueryIdFactory.newQueryUnitAttemptId(
+        QueryIdFactory.newQueryUnitId(
+                QueryIdFactory.newSubQueryId(
+                    QueryIdFactory.newQueryId())), 0);
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/org/apache/tajo/util/TajoIdUtils.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/TajoIdUtils.java b/tajo-common/src/main/java/org/apache/tajo/util/TajoIdUtils.java
new file mode 100644
index 0000000..2164d27
--- /dev/null
+++ b/tajo-common/src/main/java/org/apache/tajo/util/TajoIdUtils.java
@@ -0,0 +1,83 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.util;
+
+import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
+import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.apache.hadoop.yarn.util.BuilderUtils;
+import org.apache.tajo.QueryId;
+import org.apache.tajo.SubQueryId;
+import org.apache.tajo.TajoIdProtos.SubQueryIdProto;
+
+public class TajoIdUtils {
+  /** It is mainly for DDL statements which don's have any query id. */
+  public static final QueryId NullQueryId =
+      TajoIdUtils.createQueryId(BuilderUtils.newApplicationId(0, 0), 0);
+
+  public static QueryId createQueryId(ApplicationId appId, int attemptId) {
+    return newQueryId(appId, attemptId);
+  }
+
+  public static QueryId createQueryId(ApplicationAttemptId appAttemptId) {
+    QueryId queryId = new QueryId();
+    queryId.setApplicationId(appAttemptId.getApplicationId());
+    queryId.setAttemptId(appAttemptId.getAttemptId());
+    return queryId;
+  }
+
+  public static QueryId createQueryId(String queryId) {
+    String[] split = queryId.split(QueryId.SEPARATOR);
+    ApplicationId appId = BuilderUtils.newApplicationId(Long.valueOf(split[1]),
+        Integer.parseInt(split[2]));
+    int idInt = Integer.parseInt(split[2]);
+    return newQueryId(appId, idInt);
+  }
+
+  public static SubQueryId createSubQueryId(QueryId queryId,
+                                            int subQueryIdInt) {
+    return newSubQueryId(queryId, subQueryIdInt);
+  }
+
+  public static QueryId newQueryId(ApplicationId appId, int id) {
+    QueryId queryId = new QueryId();
+    queryId.setApplicationId(appId);
+    queryId.setAttemptId(id);
+    return queryId;
+  }
+
+  public static SubQueryId newSubQueryId(QueryId jobId, int id) {
+    SubQueryId taskId = new SubQueryId();
+    taskId.setQueryId(jobId);
+    taskId.setId(id);
+    return taskId;
+  }
+
+  public static SubQueryId newSubQueryId(String subQueryId) {
+    String [] split = subQueryId.split(QueryId.SEPARATOR);
+    ApplicationId appId = BuilderUtils.newApplicationId(Long.valueOf(split[1]),
+        Integer.valueOf(split[2]));
+    QueryId queryId = TajoIdUtils.createQueryId(appId, Integer.valueOf(split[3]));
+    return createSubQueryId(queryId, Integer.parseInt(split[4]));
+  }
+
+  public static SubQueryId newSubQueryId(SubQueryIdProto proto) {
+    SubQueryId subId = new SubQueryId(proto);
+    return subId;
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/tajo/QueryId.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/tajo/QueryId.java b/tajo-common/src/main/java/tajo/QueryId.java
deleted file mode 100644
index 64844b4..0000000
--- a/tajo-common/src/main/java/tajo/QueryId.java
+++ /dev/null
@@ -1,187 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package tajo;
-
-import org.apache.hadoop.yarn.api.records.ApplicationId;
-import org.apache.hadoop.yarn.api.records.impl.pb.ApplicationIdPBImpl;
-import org.apache.hadoop.yarn.proto.YarnProtos.ApplicationAttemptIdProto;
-import org.apache.hadoop.yarn.proto.YarnProtos.ApplicationAttemptIdProtoOrBuilder;
-import org.apache.hadoop.yarn.proto.YarnProtos.ApplicationIdProto;
-
-import java.text.NumberFormat;
-
-/**
- * QueryId represents a unique identifier of a query.
- */
-public class QueryId implements Comparable<QueryId> {
-  public static final String PREFIX = "q";
-  public static final String SEPARATOR = "_";
-
-  ApplicationAttemptIdProto proto = ApplicationAttemptIdProto
-      .getDefaultInstance();
-  ApplicationAttemptIdProto.Builder builder = null;
-  boolean viaProto = false;
-
-  private ApplicationId applicationId = null;
-
-  public QueryId() {
-    builder = ApplicationAttemptIdProto.newBuilder();
-  }
-
-  public QueryId(ApplicationAttemptIdProto proto) {
-    this.proto = proto;
-    viaProto = true;
-  }
-
-  public synchronized ApplicationAttemptIdProto getProto() {
-    mergeLocalToProto();
-    proto = viaProto ? proto : builder.build();
-    viaProto = true;
-    return proto;
-  }
-
-  private synchronized void mergeLocalToBuilder() {
-    if (this.applicationId != null
-        && !((ApplicationIdPBImpl) applicationId).getProto().equals(
-        builder.getApplicationId())) {
-      builder.setApplicationId(convertToProtoFormat(this.applicationId));
-    }
-  }
-
-  private synchronized void mergeLocalToProto() {
-    if (viaProto)
-      maybeInitBuilder();
-    mergeLocalToBuilder();
-    proto = builder.build();
-    viaProto = true;
-  }
-
-  private synchronized void maybeInitBuilder() {
-    if (viaProto || builder == null) {
-      builder = ApplicationAttemptIdProto.newBuilder(proto);
-    }
-    viaProto = false;
-  }
-
-  public synchronized int getAttemptId() {
-    ApplicationAttemptIdProtoOrBuilder p = viaProto ? proto : builder;
-    return (p.getAttemptId());
-  }
-
-  public synchronized void setAttemptId(int attemptId) {
-    maybeInitBuilder();
-    builder.setAttemptId((attemptId));
-  }
-
-  public synchronized ApplicationId getApplicationId() {
-    ApplicationAttemptIdProtoOrBuilder p = viaProto ? proto : builder;
-    if (this.applicationId != null) {
-      return this.applicationId;
-    }
-    if (!p.hasApplicationId()) {
-      return null;
-    }
-    this.applicationId = convertFromProtoFormat(p.getApplicationId());
-    return this.applicationId;
-  }
-
-  public synchronized void setApplicationId(ApplicationId appId) {
-    maybeInitBuilder();
-    if (appId == null)
-      builder.clearApplicationId();
-    this.applicationId = appId;
-  }
-
-  private ApplicationIdPBImpl convertFromProtoFormat(ApplicationIdProto p) {
-    return new ApplicationIdPBImpl(p);
-  }
-
-  private ApplicationIdProto convertToProtoFormat(ApplicationId t) {
-    return ((ApplicationIdPBImpl)t).getProto();
-  }
-
-  @Override
-  public int compareTo(QueryId queryId) {
-    int compVal = getApplicationId().compareTo(queryId.getApplicationId());
-    if (compVal != 0) {
-      return compVal;
-    } else {
-      return getAttemptId() - queryId.getAttemptId();
-    }
-  }
-
-  static final ThreadLocal<NumberFormat> appIdFormat =
-      new ThreadLocal<NumberFormat>() {
-        @Override
-        public NumberFormat initialValue() {
-          NumberFormat fmt = NumberFormat.getInstance();
-          fmt.setGroupingUsed(false);
-          fmt.setMinimumIntegerDigits(4);
-          return fmt;
-        }
-      };
-
-  static final ThreadLocal<NumberFormat> attemptIdFormat =
-      new ThreadLocal<NumberFormat>() {
-        @Override
-        public NumberFormat initialValue() {
-          NumberFormat fmt = NumberFormat.getInstance();
-          fmt.setGroupingUsed(false);
-          fmt.setMinimumIntegerDigits(6);
-          return fmt;
-        }
-      };
-
-  @Override
-  public int hashCode() {
-    // Generated by eclipse.
-    final int prime = 31;
-    int result = 1;
-    ApplicationId appId = getApplicationId();
-    result = prime * result +  appId.hashCode();
-    result = prime * result + getAttemptId();
-    return result;
-  }
-
-  @Override
-  public boolean equals(Object obj) {
-    if (this == obj)
-      return true;
-    if (obj == null)
-      return false;
-    if (getClass() != obj.getClass())
-      return false;
-    QueryId other = (QueryId) obj;
-    if (!this.getApplicationId().equals(other.getApplicationId()))
-      return false;
-    if (this.getAttemptId() != other.getAttemptId())
-      return false;
-    return true;
-  }
-
-  @Override
-  public String toString() {
-    StringBuilder sb = new StringBuilder(PREFIX).append(SEPARATOR)
-    .append(this.getApplicationId().getClusterTimestamp()).append(SEPARATOR)
-    .append(appIdFormat.get().format(this.getApplicationId().getId()))
-    .append(SEPARATOR)
-        .append(attemptIdFormat.get().format(getAttemptId()));
-    return sb.toString();
-  }
-}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/tajo/QueryIdFactory.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/tajo/QueryIdFactory.java b/tajo-common/src/main/java/tajo/QueryIdFactory.java
deleted file mode 100644
index 1237037..0000000
--- a/tajo-common/src/main/java/tajo/QueryIdFactory.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package tajo;
-
-import org.apache.hadoop.yarn.util.BuilderUtils;
-import tajo.util.TajoIdUtils;
-
-import java.util.concurrent.atomic.AtomicInteger;
-
-public class QueryIdFactory {
-  private static AtomicInteger nextId = 
-      new AtomicInteger(-1);
-  
-  public static void reset() {
-    nextId.set(-1);
-  }
-
-  public synchronized static QueryId newQueryId() {
-    int idInt = nextId.incrementAndGet();
-    return TajoIdUtils.createQueryId(BuilderUtils.newApplicationId(
-        System.currentTimeMillis(), idInt), idInt);
-  }
-  
-  public synchronized static SubQueryId newSubQueryId(QueryId queryId) {
-    return TajoIdUtils.createSubQueryId(queryId, nextId.incrementAndGet());
-  }
-  
-  public synchronized static QueryUnitId newQueryUnitId(SubQueryId subQueryId) {
-    return new QueryUnitId(subQueryId, nextId.incrementAndGet());
-  }
-
-  public synchronized static QueryUnitId newQueryUnitId(SubQueryId subQueryId, int taskId) {
-    return new QueryUnitId(subQueryId, taskId);
-  }
-
-  public synchronized static QueryUnitAttemptId newQueryUnitAttemptId(
-      final QueryUnitId queryUnitId, final int attemptId) {
-    return new QueryUnitAttemptId(queryUnitId, attemptId);
-  }
-}

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/bc6359b8/tajo-common/src/main/java/tajo/QueryUnitAttemptId.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/tajo/QueryUnitAttemptId.java b/tajo-common/src/main/java/tajo/QueryUnitAttemptId.java
deleted file mode 100644
index 71f5e19..0000000
--- a/tajo-common/src/main/java/tajo/QueryUnitAttemptId.java
+++ /dev/null
@@ -1,172 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package tajo;
-
-import com.google.common.base.Objects;
-import tajo.TajoIdProtos.QueryUnitAttemptIdProto;
-import tajo.TajoIdProtos.QueryUnitAttemptIdProtoOrBuilder;
-import tajo.common.ProtoObject;
-
-import java.text.NumberFormat;
-
-public class QueryUnitAttemptId implements Comparable<QueryUnitAttemptId>,
-    ProtoObject<QueryUnitAttemptIdProto> {
-  private static final String PREFIX="ta";
-
-  private static final NumberFormat format = NumberFormat.getInstance();
-  static {
-    format.setGroupingUsed(false);
-    format.setMinimumIntegerDigits(2);
-  }
-
-  private QueryUnitId queryUnitId = null;
-  private int id = -1;
-  private String finalId = null;
-
-  private QueryUnitAttemptIdProto proto =
-      QueryUnitAttemptIdProto.getDefaultInstance();
-  private QueryUnitAttemptIdProto.Builder builder = null;
-  private boolean viaProto = false;
-
-  public QueryUnitAttemptId() {
-    builder = QueryUnitAttemptIdProto.newBuilder();
-  }
-
-  public QueryUnitAttemptId(final QueryUnitId queryUnitId, final int id) {
-    this.queryUnitId = queryUnitId;
-    this.id = id;
-  }
-
-  public QueryUnitAttemptId(QueryUnitAttemptIdProto proto) {
-    this.proto = proto;
-    viaProto = true;
-  }
-
-  public QueryUnitAttemptId(final String finalId) {
-    this.finalId = finalId;
-    int i = finalId.lastIndexOf(QueryId.SEPARATOR);
-    this.queryUnitId = new QueryUnitId(finalId.substring(0, i));
-    this.id = Integer.valueOf(finalId.substring(i+1));
-  }
-
-  public int getId() {
-    QueryUnitAttemptIdProtoOrBuilder p = viaProto ? proto : builder;
-    if (this.id != -1) {
-      return this.id;
-    }
-    if (!p.hasId()) {
-      return -1;
-    }
-    this.id = p.getId();
-    return id;
-  }
-
-  public QueryUnitId getQueryUnitId() {
-    QueryUnitAttemptIdProtoOrBuilder p = viaProto ? proto : builder;
-    if (this.queryUnitId != null) {
-      return this.queryUnitId;
-    }
-    if (!p.hasId()) {
-      return null;
-    }
-    this.queryUnitId = new QueryUnitId(p.getQueryUnitId());
-    return queryUnitId;
-  }
-
-  public QueryId getQueryId() {
-    return this.getQueryUnitId().getQueryId();
-  }
-
-  public SubQueryId getSubQueryId() {
-    return this.getQueryUnitId().getSubQueryId();
-  }
-
-  @Override
-  public final String toString() {
-    if (finalId == null) {
-      StringBuilder sb = new StringBuilder(PREFIX);
-      SubQueryId subQueryId = getQueryUnitId().getSubQueryId();
-      QueryId appId = subQueryId.getQueryId();
-      sb.append(QueryId.SEPARATOR).append(appId.getApplicationId().getClusterTimestamp())
-          .append(QueryId.SEPARATOR).append(QueryId.appIdFormat.get().format(appId.getApplicationId().getId()))
-          .append(QueryId.SEPARATOR).append(QueryId.attemptIdFormat.get().format(appId.getAttemptId()))
-          .append(QueryId.SEPARATOR).append(SubQueryId.subQueryIdFormat.get().format(subQueryId.getId()))
-          .append(QueryId.SEPARATOR).append(QueryUnitId.queryUnitIdFormat.get().format(getQueryUnitId().getId()))
-          .append(QueryId.SEPARATOR).append(format.format(getId()));
-      finalId = sb.toString();
-    }
-    return this.finalId;
-  }
-
-  @Override
-  public final boolean equals(final Object o) {
-    if (o instanceof QueryUnitAttemptId) {
-      QueryUnitAttemptId other = (QueryUnitAttemptId) o;
-      return this.toString().equals(other.toString());
-    }
-    return false;
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hashCode(getQueryUnitId(), getId());
-  }
-
-  @Override
-  public int compareTo(QueryUnitAttemptId o) {
-    return this.getId() - o.getId();
-  }
-
-  private void mergeProtoToLocal() {
-    QueryUnitAttemptIdProtoOrBuilder p = viaProto ? proto : builder;
-    if (queryUnitId == null) {
-      queryUnitId = new QueryUnitId(p.getQueryUnitId());
-    }
-    if (id == -1) {
-      id = p.getId();
-    }
-  }
-
-  @Override
-  public void initFromProto() {
-    mergeProtoToLocal();
-  }
-
-  private void mergeLocalToBuilder() {
-    if (builder == null) {
-      builder = QueryUnitAttemptIdProto.newBuilder(proto);
-    }
-    if (this.queryUnitId != null) {
-      builder.setQueryUnitId(queryUnitId.getProto());
-    }
-    if (this.id != -1) {
-      builder.setId(id);
-    }
-  }
-
-  @Override
-  public QueryUnitAttemptIdProto getProto() {
-    if (!viaProto) {
-      mergeLocalToBuilder();
-      proto = builder.build();
-      viaProto = true;
-    }
-    return proto;
-  }
-}