HADOOP-6226. Moves BoundedByteArrayOutputStream from the tfile package to the io package and makes it available to other users (MAPREDUCE-318). Contributed by Jothi Padmanabhan.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@810451 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -162,6 +162,10 @@ Trunk (unreleased changes)
     HADOOP-6120. Add support for Avro specific and reflect data.
     (sharad via cutting)
 
+    HADOOP-6226. Moves BoundedByteArrayOutputStream from the tfile package to
+    the io package and makes it available to other users (MAPREDUCE-318). 
+    (Jothi Padmanabhan via ddas)
+
   IMPROVEMENTS
 
     HADOOP-4565. Added CombineFileInputFormat to use data locality information

src/java/org/apache/hadoop/io/BoundedByteArrayOutputStream.java

@@ -15,7 +15,7 @@
  * the License.
  */
 
-package org.apache.hadoop.io.file.tfile;
+package org.apache.hadoop.io;
 
 import java.io.EOFException;
 import java.io.IOException;
@@ -26,15 +26,26 @@ import java.io.OutputStream;
  * than the buffer capacity. The object can be reused through <code>reset</code>
  * API and choose different limits in each round.
  */
-class BoundedByteArrayOutputStream extends OutputStream {
+public class BoundedByteArrayOutputStream extends OutputStream {
   private final byte[] buffer;
   private int limit;
   private int count;
 
+  /**
+   * Create a BoundedByteArrayOutputStream with the specified
+   * capacity
+   * @param capacity The capacity of the underlying byte array
+   */
   public BoundedByteArrayOutputStream(int capacity) {
     this(capacity, capacity);
   }
 
+  /**
+   * Create a BoundedByteArrayOutputStream with the specified
+   * capacity and limit.
+   * @param capacity The capacity of the underlying byte array
+   * @param limit The maximum limit upto which data can be written
+   */
   public BoundedByteArrayOutputStream(int capacity, int limit) {
     if ((capacity < limit) || (capacity | limit) < 0) {
       throw new IllegalArgumentException("Invalid capacity/limit");
@@ -69,6 +80,10 @@ class BoundedByteArrayOutputStream extends OutputStream {
     count += len;
   }
 
+  /**
+   * Reset the limit 
+   * @param newlim New Limit
+   */
   public void reset(int newlim) {
     if (newlim > buffer.length) {
       throw new IndexOutOfBoundsException("Limit exceeds buffer size");
@@ -77,19 +92,27 @@ class BoundedByteArrayOutputStream extends OutputStream {
     this.count = 0;
   }
 
+  /** Reset the buffer */
   public void reset() {
     this.limit = buffer.length;
     this.count = 0;
   }
 
+  /** Return the current limit */
   public int getLimit() {
     return limit;
   }
 
+  /** Returns the underlying buffer.
+   *  Data is only valid to {@link #size()}.
+   */
   public byte[] getBuffer() {
     return buffer;
   }
 
+  /** Returns the length of the valid data 
+   * currently in the buffer.
+   */
   public int size() {
     return count;
   }

src/java/org/apache/hadoop/io/file/tfile/TFile.java

@@ -34,6 +34,7 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.io.BoundedByteArrayOutputStream;
 import org.apache.hadoop.io.BytesWritable;
 import org.apache.hadoop.io.DataInputBuffer;
 import org.apache.hadoop.io.DataOutputBuffer;

src/test/core/org/apache/hadoop/io/TestBoundedByteArrayOutputStream.java

@@ -0,0 +1,91 @@
+/**
+ * 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.io;
+
+import java.io.IOException;
+
+import junit.framework.TestCase;
+import java.util.Arrays;
+import java.util.Random;
+
+
+/** Unit tests for BoundedByteArrayOutputStream */
+public class TestBoundedByteArrayOutputStream extends TestCase {
+
+  private static final int SIZE = 1024;
+  private static final byte[] INPUT = new byte[SIZE];
+  static {
+      new Random().nextBytes(INPUT);
+  }
+  
+  public void testBoundedStream() throws IOException {
+    
+    BoundedByteArrayOutputStream stream = 
+      new BoundedByteArrayOutputStream(SIZE);
+
+    // Write to the stream, get the data back and check for contents
+    stream.write(INPUT, 0, SIZE);
+    assertTrue("Array Contents Mismatch",
+        Arrays.equals(INPUT, stream.getBuffer()));
+    
+    // Try writing beyond end of buffer. Should throw an exception
+    boolean caughtException = false;
+    
+    try {
+      stream.write(INPUT[0]);
+    } catch (Exception e) {
+      caughtException = true;
+    }
+    
+    assertTrue("Writing beyond limit did not throw an exception",
+        caughtException);
+    
+    //Reset the stream and try, should succeed 
+    stream.reset();
+    assertTrue("Limit did not get reset correctly", 
+        (stream.getLimit() == SIZE));
+    stream.write(INPUT, 0, SIZE);
+    assertTrue("Array Contents Mismatch",
+        Arrays.equals(INPUT, stream.getBuffer()));
+  
+    // Try writing one more byte, should fail
+    caughtException = false;
+    try {
+      stream.write(INPUT[0]);
+    } catch (Exception e) {
+      caughtException = true;
+    }
+  
+    // Reset the stream, but set a lower limit. Writing beyond
+    // the limit should throw an exception
+    stream.reset(SIZE - 1);
+    assertTrue("Limit did not get reset correctly",
+        (stream.getLimit() == SIZE -1));
+    caughtException = false;
+    
+    try {
+      stream.write(INPUT, 0, SIZE);
+    } catch (Exception e) {
+      caughtException = true;
+    }
+    
+    assertTrue("Writing beyond limit did not throw an exception",
+        caughtException);
+  }
+}