svn commit: r635218 - in /lucene/mahout/trunk/src: main/java/org/apache/mahout/utils/Point.java test/java/org/apache/mahout/utils/TestPoint.java

[dw...@apache.org]

Author: dweiss
Date: Sun Mar  9 04:13:52 2008
New Revision: 635218

URL: http://svn.apache.org/viewvc?rev=635218&view=rev
Log:
Comitting https://issues.apache.org/jira/browse/MAHOUT-12 (point format parsing/ emitting).

Added:
    lucene/mahout/trunk/src/test/java/org/apache/mahout/utils/TestPoint.java
Modified:
    lucene/mahout/trunk/src/main/java/org/apache/mahout/utils/Point.java

Modified: lucene/mahout/trunk/src/main/java/org/apache/mahout/utils/Point.java
URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/src/main/java/org/apache/mahout/utils/Point.java?rev=635218&r1=635217&r2=635218&view=diff
==============================================================================
--- lucene/mahout/trunk/src/main/java/org/apache/mahout/utils/Point.java (original)
+++ lucene/mahout/trunk/src/main/java/org/apache/mahout/utils/Point.java Sun Mar  9 04:13:52 2008
@@ -20,8 +20,13 @@
 import java.io.FileWriter;
 import java.io.IOException;
 import java.util.List;
+import java.util.regex.Pattern;
 
 public class Point {
+  /**
+   * Split pattern for {@link #decodePoint(String)}.
+   */
+  private final static Pattern splitPattern = Pattern.compile("[,]");
 
   /**
    * Format the point for input to a Mapper or Reducer
@@ -30,30 +35,39 @@
    * @return a String
    */
   public static String formatPoint(Float[] point) {
-    String out = "";
-    out += "[";
-    for (int i = 0; i < point.length; i++)
-      out += point[i] + ", ";
-    out += "] ";
-    String ptOut = out;
-    return ptOut;
+    if (point.length == 0) {
+      return "[]";
+    }
+
+    final StringBuilder out = new StringBuilder();
+    out.append('[');
+    for (int i = 0; i < point.length; i++) {
+      if (i > 0) out.append(", ");
+      out.append(point[i]);
+    }
+    out.append(']');
+    return out.toString();
   }
 
   /**
    * Decodes a point from its string representation.
    *
    * @param formattedString a comma-terminated String of the form
-   *                        "[v1,v2,...,vn,]"
+   *                        "[v1,v2,...,vn]"
    * @return the Float[] defining an n-dimensional point
    */
   public static Float[] decodePoint(String formattedString) {
-    String[] pts = formattedString.split(",");
-    Float[] point = new Float[pts.length - 1];
-    for (int i = 0; i < point.length; i++)
-      if (pts[i].startsWith("["))
-        point[i] = new Float(pts[i].substring(1));
-      else if (!pts[i].startsWith("]"))
-        point[i] = new Float(pts[i]);
+    if (formattedString.charAt(0) != '[' 
+      || formattedString.charAt(formattedString.length() - 1) != ']') {
+      throw new IllegalArgumentException(formattedString);
+    }
+    formattedString = formattedString.substring(1, formattedString.length() - 2);
+
+    final String[] pts = splitPattern.split(formattedString);
+    final Float[] point = new Float[pts.length];
+    for (int i = 0; i < point.length; i++) {
+      point[i] = new Float(pts[i]);
+    }
     return point;
   }
 
@@ -65,8 +79,7 @@
    * @return
    */
   public static String ptOut(String out, Float[] pt) {
-    out += formatPoint(pt);
-    return out;
+    return out + formatPoint(pt);
   }
 
   /**

Added: lucene/mahout/trunk/src/test/java/org/apache/mahout/utils/TestPoint.java
URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/src/test/java/org/apache/mahout/utils/TestPoint.java?rev=635218&view=auto
==============================================================================
--- lucene/mahout/trunk/src/test/java/org/apache/mahout/utils/TestPoint.java (added)
+++ lucene/mahout/trunk/src/test/java/org/apache/mahout/utils/TestPoint.java Sun Mar  9 04:13:52 2008
@@ -0,0 +1,30 @@
+package org.apache.mahout.utils;
+
+import junit.framework.TestCase;
+
+/**
+ * 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
+ * <p/>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p/>
+ * 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.
+ */
+
+public class TestPoint extends TestCase {
+  public void testFormatPoint() {
+    assertEquals("[1.0, 1.5]", Point.formatPoint(new Float [] {1.0f, 1.5f}));
+  }
+  
+  public void testPtOut() {
+    assertEquals("abc[1.0, 1.5]", Point.ptOut("abc", new Float [] {1.0f, 1.5f}));
+  }
+}