/**
* 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.hdfs.protocol;
import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hdfs.server.common.GenerationStamp;
import org.apache.hadoop.io.*;
/**************************************************
* A Block is a Hadoop FS primitive, identified by a
* long.
*
**************************************************/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class Block implements Writable, Comparable<Block> {
public static final String BLOCK_FILE_PREFIX = "blk_";
public static final String METADATA_EXTENSION = ".meta";
static { // register a ctor
WritableFactories.setFactory
(Block.class,
new WritableFactory() {
@Override
public Writable newInstance() { return new Block(); }
});
}
public static final Pattern blockFilePattern = Pattern
.compile(BLOCK_FILE_PREFIX + "(-??\\d++)$");
public static final Pattern metaFilePattern = Pattern
.compile(BLOCK_FILE_PREFIX + "(-??\\d++)_(\\d++)\\" + METADATA_EXTENSION
+ "$");
public static boolean isBlockFilename(File f) {
String name = f.getName();
return blockFilePattern.matcher(name).matches();
}
public static long filename2id(String name) {
Matcher m = blockFilePattern.matcher(name);
return m.matches() ? Long.parseLong(m.group(1)) : 0;
}
public static boolean isMetaFilename(String name) {
return metaFilePattern.matcher(name).matches();
}
/**
* Get generation stamp from the name of the metafile name
*/
public static long getGenerationStamp(String metaFile) {
Matcher m = metaFilePattern.matcher(metaFile);
return m.matches() ? Long.parseLong(m.group(2))
: GenerationStamp.GRANDFATHER_GENERATION_STAMP;
}
/**
* Get the blockId from the name of the metafile name
*/
public static long getBlockId(String metaFile) {
Matcher m = metaFilePattern.matcher(metaFile);
return m.matches() ? Long.parseLong(m.group(1)) : 0;
}
private long blockId;
private long numBytes;
private long generationStamp;
public Block() {this(0, 0, 0);}
public Block(final long blkid, final long len, final long generationStamp) {
set(blkid, len, generationStamp);
}
public Block(final long blkid) {
this(blkid, 0, GenerationStamp.GRANDFATHER_GENERATION_STAMP);
}
public Block(Block blk) {
this(blk.blockId, blk.numBytes, blk.generationStamp);
}
/**
* Find the blockid from the given filename
*/
public Block(File f, long len, long genstamp) {
this(filename2id(f.getName()), len, genstamp);
}
public void set(long blkid, long len, long genStamp) {
this.blockId = blkid;
this.numBytes = len;
this.generationStamp = genStamp;
}
/**
*/
public long getBlockId() {
return blockId;
}
public void setBlockId(long bid) {
blockId = bid;
}
/**
*/
public String getBlockName() {
return BLOCK_FILE_PREFIX + String.valueOf(blockId);
}
/**
*/
public long getNumBytes() {
return numBytes;
}
public void setNumBytes(long len) {
this.numBytes = len;
}
public long getGenerationStamp() {
return generationStamp;
}
public void setGenerationStamp(long stamp) {
generationStamp = stamp;
}
/**
*/
@Override
public String toString() {
return getBlockName() + "_" + getGenerationStamp();
}
public void appendStringTo(StringBuilder sb) {
sb.append(BLOCK_FILE_PREFIX)
.append(blockId)
.append("_")
.append(getGenerationStamp());
}
/////////////////////////////////////
// Writable
/////////////////////////////////////
@Override // Writable
public void write(DataOutput out) throws IOException {
writeHelper(out);
}
@Override // Writable
public void readFields(DataInput in) throws IOException {
readHelper(in);
}
final void writeHelper(DataOutput out) throws IOException {
out.writeLong(blockId);
out.writeLong(numBytes);
out.writeLong(generationStamp);
}
final void readHelper(DataInput in) throws IOException {
this.blockId = in.readLong();
this.numBytes = in.readLong();
this.generationStamp = in.readLong();
if (numBytes < 0) {
throw new IOException("Unexpected block size: " + numBytes);
}
}
// write only the identifier part of the block
public void writeId(DataOutput out) throws IOException {
out.writeLong(blockId);
out.writeLong(generationStamp);
}
// Read only the identifier part of the block
public void readId(DataInput in) throws IOException {
this.blockId = in.readLong();
this.generationStamp = in.readLong();
}
@Override // Comparable
public int compareTo(Block b) {
return blockId < b.blockId ? -1 :
blockId > b.blockId ? 1 : 0;
}
@Override // Object
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof Block)) {
return false;
}
return compareTo((Block)o) == 0;
}
/**
* @return true if the two blocks have the same block ID and the same
* generation stamp, or if both blocks are null.
*/
public static boolean matchingIdAndGenStamp(Block a, Block b) {
if (a == b) return true; // same block, or both null
if (a == null || b == null) return false; // only one null
return a.blockId == b.blockId &&
a.generationStamp == b.generationStamp;
}
@Override // Object
public int hashCode() {
//GenerationStamp is IRRELEVANT and should not be used here
return (int)(blockId^(blockId>>>32));
}
}