HADOOP-310. Additional constructor requested in BytesWritable. (Brock Noland via atm)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1140010 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Aaron Myers 2011-06-27 03:39:04 +00:00
parent 9c83d16c81
commit b866ff64d9
3 changed files with 57 additions and 3 deletions

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@ -234,6 +234,9 @@ Trunk (unreleased changes)
HADOOP-7385. Remove StringUtils.stringifyException(ie) in logger functions.
(Bharath Mundlapudi via Tanping Wang).
HADOOP-310. Additional constructor requested in BytesWritable. (Brock
Noland via atm)
OPTIMIZATIONS
HADOOP-7333. Performance improvement in PureJavaCrc32. (Eric Caspole

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@ -51,8 +51,19 @@ public class BytesWritable extends BinaryComparable
* @param bytes This array becomes the backing storage for the object.
*/
public BytesWritable(byte[] bytes) {
this(bytes, bytes.length);
}
/**
* Create a BytesWritable using the byte array as the initial value
* and length as the length. Use this constructor if the array is larger
* than the value it represents.
* @param bytes This array becomes the backing storage for the object.
* @param length The number of bytes to use from array.
*/
public BytesWritable(byte[] bytes, int length) {
this.bytes = bytes;
this.size = bytes.length;
this.size = length;
}
/**

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@ -17,13 +17,17 @@
*/
package org.apache.hadoop.io;
import junit.framework.TestCase;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
/**
* This is the unit test for BytesWritable.
*/
public class TestBytesWritable extends TestCase {
public class TestBytesWritable {
@Test
public void testSizeChange() throws Exception {
byte[] hadoop = "hadoop".getBytes();
BytesWritable buf = new BytesWritable(hadoop);
@ -50,6 +54,7 @@ public class TestBytesWritable extends TestCase {
assertEquals(hadoop[0], buf.getBytes()[0]);
}
@Test
public void testHash() throws Exception {
byte[] owen = "owen".getBytes();
BytesWritable buf = new BytesWritable(owen);
@ -60,6 +65,7 @@ public class TestBytesWritable extends TestCase {
assertEquals(1, buf.hashCode());
}
@Test
public void testCompare() throws Exception {
byte[][] values = new byte[][]{"abc".getBytes(),
"ad".getBytes(),
@ -88,10 +94,44 @@ public class TestBytesWritable extends TestCase {
assertEquals(expected, actual);
}
@Test
public void testToString() {
checkToString(new byte[]{0,1,2,0x10}, "00 01 02 10");
checkToString(new byte[]{-0x80, -0x7f, -0x1, -0x2, 1, 0},
"80 81 ff fe 01 00");
}
/**
* This test was written as result of adding the new zero
* copy constructor and set method to BytesWritable. These
* methods allow users to specify the backing buffer of the
* BytesWritable instance and a length.
*/
@Test
public void testZeroCopy() {
byte[] bytes = "brock".getBytes();
BytesWritable zeroBuf = new BytesWritable(bytes, bytes.length); // new
BytesWritable copyBuf = new BytesWritable(bytes); // old
// using zero copy constructor shouldn't result in a copy
assertTrue("copy took place, backing array != array passed to constructor",
bytes == zeroBuf.getBytes());
assertTrue("length of BW should backing byte array", zeroBuf.getLength() == bytes.length);
assertEquals("objects with same backing array should be equal", zeroBuf, copyBuf);
assertEquals("string repr of objects with same backing array should be equal",
zeroBuf.toString(), copyBuf.toString());
assertTrue("compare order objects with same backing array should be equal",
zeroBuf.compareTo(copyBuf) == 0);
assertTrue("hash of objects with same backing array should be equal",
zeroBuf.hashCode() == copyBuf.hashCode());
// ensure expanding buffer is handled correctly
// for buffers created with zero copy api
byte[] buffer = new byte[bytes.length * 5];
zeroBuf.set(buffer, 0, buffer.length); // expand internal buffer
zeroBuf.set(bytes, 0, bytes.length); // set back to normal contents
assertEquals("buffer created with (array, len) has bad contents",
zeroBuf, copyBuf);
assertTrue("buffer created with (array, len) has bad length",
zeroBuf.getLength() == copyBuf.getLength());
}
}