HADOOP-1498. Add file missed in prior commit.

git-svn-id: https://svn.apache.org/repos/asf/lucene/hadoop/trunk/src/contrib/hbase@548794 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Doug Cutting 2007-06-19 16:40:59 +00:00
parent eef130fc91
commit 2447ce1922
1 changed files with 200 additions and 0 deletions

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/**
* 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.io;
import java.io.IOException;
import java.io.DataInput;
import java.io.DataOutput;
import java.util.List;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;
/**
* A byte sequence that is usable as a key or value. Based on
* {@link org.apache.hadoop.io.BytesWritable} only this class is NOT resizable
* and DOES NOT distinguish between the size of the seqeunce and the current
* capacity as {@link org.apache.hadoop.io.BytesWritable} does. Hence its
* comparatively 'immutable'.
*/
public class ImmutableBytesWritable implements WritableComparable {
private byte[] bytes;
/**
* Create a zero-size sequence.
*/
public ImmutableBytesWritable() {
super();
}
/**
* Create a ImmutableBytesWritable using the byte array as the initial value.
* @param bytes This array becomes the backing storage for the object.
*/
public ImmutableBytesWritable(byte[] bytes) {
this.bytes = bytes;
}
/**
* Set the new ImmutableBytesWritable to a copy of the contents of the passed
* <code>ibw</code>.
* @param ibw the value to set this ImmutableBytesWritable to.
*/
public ImmutableBytesWritable(final ImmutableBytesWritable ibw) {
this(ibw.get(), 0, ibw.getSize());
}
/**
* Set the value to a copy of the given byte range
* @param newData the new values to copy in
* @param offset the offset in newData to start at
* @param length the number of bytes to copy
*/
public ImmutableBytesWritable(final byte[] newData, final int offset,
final int length) {
this.bytes = new byte[length];
System.arraycopy(newData, offset, this.bytes, 0, length);
}
/**
* Get the data from the BytesWritable.
* @return The data is only valid between 0 and getSize() - 1.
*/
public byte[] get() {
if (this.bytes == null) {
throw new IllegalStateException("Uninitialiized. Null constructor " +
"called w/o accompaying readFields invocation");
}
return this.bytes;
}
/**
* Get the current size of the buffer.
*/
public int getSize() {
if (this.bytes == null) {
throw new IllegalStateException("Uninitialiized. Null constructor " +
"called w/o accompaying readFields invocation");
}
return this.bytes.length;
}
// inherit javadoc
public void readFields(final DataInput in) throws IOException {
this.bytes = new byte[in.readInt()];
in.readFully(this.bytes, 0, this.bytes.length);
}
// inherit javadoc
public void write(final DataOutput out) throws IOException {
out.writeInt(this.bytes.length);
out.write(this.bytes, 0, this.bytes.length);
}
// Below methods copied from BytesWritable
public int hashCode() {
return WritableComparator.hashBytes(bytes, this.bytes.length);
}
/**
* Define the sort order of the BytesWritable.
* @param right_obj The other bytes writable
* @return Positive if left is bigger than right, 0 if they are equal, and
* negative if left is smaller than right.
*/
public int compareTo(Object right_obj) {
return compareTo(((ImmutableBytesWritable)right_obj).get());
}
public int compareTo(final byte [] that) {
int diff = this.bytes.length - that.length;
return (diff != 0)?
diff:
WritableComparator.compareBytes(this.bytes, 0, this.bytes.length, that,
0, that.length);
}
/**
* Are the two byte sequences equal?
*/
public boolean equals(Object right_obj) {
if (right_obj instanceof ImmutableBytesWritable) {
return compareTo(right_obj) == 0;
}
return false;
}
/**
* Generate the stream of bytes as hex pairs separated by ' '.
*/
public String toString() {
StringBuffer sb = new StringBuffer(3*this.bytes.length);
for (int idx = 0; idx < this.bytes.length; idx++) {
// if not the first, put a blank separator in
if (idx != 0) {
sb.append(' ');
}
String num = Integer.toHexString(bytes[idx]);
// if it is only one digit, add a leading 0.
if (num.length() < 2) {
sb.append('0');
}
sb.append(num);
}
return sb.toString();
}
/** A Comparator optimized for ImmutableBytesWritable.
*/
public static class Comparator extends WritableComparator {
private BytesWritable.Comparator comparator =
new BytesWritable.Comparator();
public Comparator() {
super(ImmutableBytesWritable.class);
}
/**
* Compare the buffers in serialized form.
*/
public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
return comparator.compare(b1, s1, l1, b2, s2, l2);
}
}
static { // register this comparator
WritableComparator.define(ImmutableBytesWritable.class, new Comparator());
}
/**
* @param array List of byte [].
* @return Array of byte [].
*/
public static byte [][] toArray(final List<byte []> array) {
// List#toArray doesn't work on lists of byte [].
byte[][] results = new byte[array.size()][];
for (int i = 0; i < array.size(); i++) {
results[i] = array.get(i);
}
return results;
}
}