/**
* 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.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableFactories;
import org.apache.hadoop.io.WritableFactory;
import org.apache.avro.reflect.Nullable;
/**
* Collection of blocks with their locations and the file length.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class LocatedBlocks implements Writable {
private long fileLength;
private List<LocatedBlock> blocks; // array of blocks with prioritized locations
private boolean underConstruction;
@Nullable
private LocatedBlock lastLocatedBlock = null;
private boolean isLastBlockComplete = false;
public LocatedBlocks() {
fileLength = 0;
blocks = null;
underConstruction = false;
}
/** public Constructor */
public LocatedBlocks(long flength, boolean isUnderConstuction,
List<LocatedBlock> blks,
LocatedBlock lastBlock, boolean isLastBlockCompleted) {
fileLength = flength;
blocks = blks;
underConstruction = isUnderConstuction;
this.lastLocatedBlock = lastBlock;
this.isLastBlockComplete = isLastBlockCompleted;
}
/**
* Get located blocks.
*/
public List<LocatedBlock> getLocatedBlocks() {
return blocks;
}
/** Get the last located block. */
public LocatedBlock getLastLocatedBlock() {
return lastLocatedBlock;
}
/** Is the last block completed? */
public boolean isLastBlockComplete() {
return isLastBlockComplete;
}
/**
* Get located block.
*/
public LocatedBlock get(int index) {
return blocks.get(index);
}
/**
* Get number of located blocks.
*/
public int locatedBlockCount() {
return blocks == null ? 0 : blocks.size();
}
/**
*
*/
public long getFileLength() {
return this.fileLength;
}
/**
* Return ture if file was under construction when
* this LocatedBlocks was constructed, false otherwise.
*/
public boolean isUnderConstruction() {
return underConstruction;
}
/**
* Find block containing specified offset.
*
* @return block if found, or null otherwise.
*/
public int findBlock(long offset) {
// create fake block of size 1 as a key
LocatedBlock key = new LocatedBlock();
key.setStartOffset(offset);
key.getBlock().setNumBytes(1);
Comparator<LocatedBlock> comp =
new Comparator<LocatedBlock>() {
// Returns 0 iff a is inside b or b is inside a
public int compare(LocatedBlock a, LocatedBlock b) {
long aBeg = a.getStartOffset();
long bBeg = b.getStartOffset();
long aEnd = aBeg + a.getBlockSize();
long bEnd = bBeg + b.getBlockSize();
if(aBeg <= bBeg && bEnd <= aEnd
|| bBeg <= aBeg && aEnd <= bEnd)
return 0; // one of the blocks is inside the other
if(aBeg < bBeg)
return -1; // a's left bound is to the left of the b's
return 1;
}
};
return Collections.binarySearch(blocks, key, comp);
}
public void insertRange(int blockIdx, List<LocatedBlock> newBlocks) {
int oldIdx = blockIdx;
int insStart = 0, insEnd = 0;
for(int newIdx = 0; newIdx < newBlocks.size() && oldIdx < blocks.size();
newIdx++) {
long newOff = newBlocks.get(newIdx).getStartOffset();
long oldOff = blocks.get(oldIdx).getStartOffset();
if(newOff < oldOff) {
insEnd++;
} else if(newOff == oldOff) {
// replace old cached block by the new one
blocks.set(oldIdx, newBlocks.get(newIdx));
if(insStart < insEnd) { // insert new blocks
blocks.addAll(oldIdx, newBlocks.subList(insStart, insEnd));
oldIdx += insEnd - insStart;
}
insStart = insEnd = newIdx+1;
oldIdx++;
} else { // newOff > oldOff
assert false : "List of LocatedBlock must be sorted by startOffset";
}
}
insEnd = newBlocks.size();
if(insStart < insEnd) { // insert new blocks
blocks.addAll(oldIdx, newBlocks.subList(insStart, insEnd));
}
}
public static int getInsertIndex(int binSearchResult) {
return binSearchResult >= 0 ? binSearchResult : -(binSearchResult+1);
}
//////////////////////////////////////////////////
// Writable
//////////////////////////////////////////////////
static { // register a ctor
WritableFactories.setFactory
(LocatedBlocks.class,
new WritableFactory() {
public Writable newInstance() { return new LocatedBlocks(); }
});
}
public void write(DataOutput out) throws IOException {
out.writeLong(this.fileLength);
out.writeBoolean(underConstruction);
//write the last located block
final boolean isNull = lastLocatedBlock == null;
out.writeBoolean(isNull);
if (!isNull) {
lastLocatedBlock.write(out);
}
out.writeBoolean(isLastBlockComplete);
// write located blocks
int nrBlocks = locatedBlockCount();
out.writeInt(nrBlocks);
if (nrBlocks == 0) {
return;
}
for (LocatedBlock blk : this.blocks) {
blk.write(out);
}
}
public void readFields(DataInput in) throws IOException {
this.fileLength = in.readLong();
underConstruction = in.readBoolean();
//read the last located block
final boolean isNull = in.readBoolean();
if (!isNull) {
lastLocatedBlock = LocatedBlock.read(in);
}
isLastBlockComplete = in.readBoolean();
// read located blocks
int nrBlocks = in.readInt();
this.blocks = new ArrayList<LocatedBlock>(nrBlocks);
for (int idx = 0; idx < nrBlocks; idx++) {
LocatedBlock blk = new LocatedBlock();
blk.readFields(in);
this.blocks.add(blk);
}
}
/** {@inheritDoc} */
@Override
public String toString() {
final StringBuilder b = new StringBuilder(getClass().getSimpleName());
b.append("{")
.append("\n fileLength=").append(fileLength)
.append("\n underConstruction=").append(underConstruction)
.append("\n blocks=").append(blocks)
.append("\n lastLocatedBlock=").append(lastLocatedBlock)
.append("\n isLastBlockComplete=").append(isLastBlockComplete)
.append("}");
return b.toString();
}
}