svn commit: r1183571 - /hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java

[ns...@apache.org]

Author: nspiegelberg
Date: Sat Oct 15 00:06:01 2011
New Revision: 1183571

URL: http://svn.apache.org/viewvc?rev=1183571&view=rev
Log:
HBASE-4241 (forgot to include new file)

Revert Plan:

Added:
    hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java

Added: hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java?rev=1183571&view=auto
==============================================================================
--- hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java (added)
+++ hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java Sat Oct 15 00:06:01 2011
@@ -0,0 +1,129 @@
+/*
+ * Copyright 2011 The Apache Software Foundation
+ *
+ * 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.hadoop.hbase.util;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.SortedSet;
+
+import org.apache.hadoop.hbase.KeyValue;
+import org.apache.hadoop.hbase.regionserver.NonLazyKeyValueScanner;
+
+/**
+ * Utility scanner that wraps a sortable collection and serves as a
+ * KeyValueScanner.
+ */
+public class CollectionBackedScanner extends NonLazyKeyValueScanner {
+  final private Iterable<KeyValue> data;
+  final KeyValue.KVComparator comparator;
+  private Iterator<KeyValue> iter;
+  private KeyValue current;
+  private boolean closed = false;
+  private boolean isSeekDone = false;
+
+  public CollectionBackedScanner(SortedSet<KeyValue> set,
+      KeyValue.KVComparator comparator) {
+    this.comparator = comparator;
+    data = set;
+    init();
+  }
+
+  public CollectionBackedScanner(List<KeyValue> list,
+      KeyValue.KVComparator comparator) {
+    Collections.sort(list, comparator);
+    this.comparator = comparator;
+    data = list;
+    init();
+  }
+
+  public CollectionBackedScanner(KeyValue.KVComparator comparator,
+      KeyValue... array) {
+    this.comparator = comparator;
+
+    List<KeyValue> tmp = new ArrayList<KeyValue>(array.length);
+    for (int i = 0; i < array.length; ++i) {
+      tmp.add(array[i]);
+    }
+    Collections.sort(tmp, comparator);
+    data = tmp;
+    init();
+  }
+
+  private void init() {
+    iter = data.iterator();
+    if (iter.hasNext()) {
+      current = iter.next();
+    }
+  }
+
+  @Override
+  public KeyValue peek() {
+    return isSeekDone ? current : null;
+  }
+
+  @Override
+  public KeyValue next() {
+    KeyValue oldCurrent = current;
+    if (iter.hasNext()) {
+      current = iter.next();
+    } else {
+      current = null;
+    }
+    return oldCurrent;
+  }
+
+  @Override
+  public boolean seek(KeyValue seekKv) {
+    // restart iterator
+    this.isSeekDone = true;
+    iter = data.iterator();
+    return reseek(seekKv);
+  }
+
+  @Override
+  public boolean reseek(KeyValue seekKv) {
+    while (iter.hasNext()) {
+      KeyValue next = iter.next();
+      int ret = comparator.compare(next, seekKv);
+      if (ret >= 0) {
+        current = next;
+        return true;
+      }
+    }
+    return false;
+  }
+
+  @Override
+  public long getSequenceID() {
+    return 0;
+  }
+
+  public boolean isClosed() {
+    return closed;
+  }
+
+  @Override
+  public void close() {
+    closed = true;
+  }
+
+}