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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.hdfs.protocol;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import com.google.common.base.Preconditions;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.hdfs.security.token.block.BlockTokenIdentifier;
import org.apache.hadoop.security.token.Token;
import com.google.common.collect.Lists;
/**
* Associates a block with the Datanodes that contain its replicas
* and other block metadata (E.g. the file offset associated with this
* block, whether it is corrupt, a location is cached in memory,
* security token, etc).
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class LocatedBlock {
/**
* Comparator that ensures that a PROVIDED storage type is greater than any
* other storage type. Any other storage types are considered equal.
*/
private static class ProvidedLastComparator
implements Comparator, Serializable {
private static final long serialVersionUID = 6441720011443190984L;
@Override
public int compare(DatanodeInfoWithStorage dns1,
DatanodeInfoWithStorage dns2) {
if (StorageType.PROVIDED.equals(dns1.getStorageType())
&& !StorageType.PROVIDED.equals(dns2.getStorageType())) {
return 1;
}
if (!StorageType.PROVIDED.equals(dns1.getStorageType())
&& StorageType.PROVIDED.equals(dns2.getStorageType())) {
return -1;
}
// Storage types of dns1 and dns2 are now both provided or not provided;
// thus, are essentially equal for the purpose of this comparator.
return 0;
}
}
private final ExtendedBlock b;
private long offset; // offset of the first byte of the block in the file
private final DatanodeInfoWithStorage[] locs;
/** Cached storage ID for each replica */
private final String[] storageIDs;
/** Cached storage type for each replica, if reported. */
private final StorageType[] storageTypes;
// corrupt flag is true if all of the replicas of a block are corrupt.
// else false. If block has few corrupt replicas, they are filtered and
// their locations are not part of this object
private boolean corrupt;
private Token blockToken = new Token<>();
// use one instance of the Provided comparator as it uses no state.
private static ProvidedLastComparator providedLastComparator =
new ProvidedLastComparator();
/**
* List of cached datanode locations
*/
private DatanodeInfo[] cachedLocs;
// Used when there are no locations
static final DatanodeInfoWithStorage[] EMPTY_LOCS =
new DatanodeInfoWithStorage[0];
public LocatedBlock(ExtendedBlock b, DatanodeInfo[] locs) {
// By default, startOffset is unknown(-1) and corrupt is false.
this(b, convert(locs, null, null), null, null, -1, false, EMPTY_LOCS);
}
public LocatedBlock(ExtendedBlock b, DatanodeInfo[] locs,
String[] storageIDs, StorageType[] storageTypes) {
this(b, convert(locs, storageIDs, storageTypes),
storageIDs, storageTypes, -1, false, EMPTY_LOCS);
}
public LocatedBlock(ExtendedBlock b, DatanodeInfo[] locs,
String[] storageIDs, StorageType[] storageTypes, long startOffset,
boolean corrupt, DatanodeInfo[] cachedLocs) {
this(b, convert(locs, storageIDs, storageTypes),
storageIDs, storageTypes, startOffset, corrupt,
null == cachedLocs || 0 == cachedLocs.length ? EMPTY_LOCS : cachedLocs);
}
public LocatedBlock(ExtendedBlock b, DatanodeInfoWithStorage[] locs,
String[] storageIDs, StorageType[] storageTypes, long startOffset,
boolean corrupt, DatanodeInfo[] cachedLocs) {
this.b = b;
this.offset = startOffset;
this.corrupt = corrupt;
this.locs = null == locs ? EMPTY_LOCS : locs;
this.storageIDs = storageIDs;
this.storageTypes = storageTypes;
this.cachedLocs = null == cachedLocs || 0 == cachedLocs.length
? EMPTY_LOCS
: cachedLocs;
}
private static DatanodeInfoWithStorage[] convert(
DatanodeInfo[] infos, String[] storageIDs, StorageType[] storageTypes) {
if (null == infos) {
return EMPTY_LOCS;
}
DatanodeInfoWithStorage[] ret = new DatanodeInfoWithStorage[infos.length];
for(int i = 0; i < infos.length; i++) {
ret[i] = new DatanodeInfoWithStorage(infos[i],
storageIDs != null ? storageIDs[i] : null,
storageTypes != null ? storageTypes[i] : null);
}
return ret;
}
public Token getBlockToken() {
return blockToken;
}
public void setBlockToken(Token token) {
this.blockToken = token;
}
public ExtendedBlock getBlock() {
return b;
}
/**
* Returns the locations associated with this block. The returned array is not
* expected to be modified. If it is, caller must immediately invoke
* {@link org.apache.hadoop.hdfs.protocol.LocatedBlock#updateCachedStorageInfo}
* to update the cached Storage ID/Type arrays.
*/
public DatanodeInfo[] getLocations() {
return locs;
}
public StorageType[] getStorageTypes() {
return storageTypes;
}
public String[] getStorageIDs() {
return storageIDs;
}
/**
* Updates the cached StorageID and StorageType information. Must be
* called when the locations array is modified.
*/
public void updateCachedStorageInfo() {
if (storageIDs != null) {
for(int i = 0; i < locs.length; i++) {
storageIDs[i] = locs[i].getStorageID();
}
}
if (storageTypes != null) {
for(int i = 0; i < locs.length; i++) {
storageTypes[i] = locs[i].getStorageType();
}
}
}
/**
* Moves all locations that have {@link StorageType}
* {@code PROVIDED} to the end of the locations array without
* changing the relative ordering of the remaining locations
* Only the first {@code activeLen} locations are considered.
* The caller must immediately invoke {@link
* org.apache.hadoop.hdfs.protocol.LocatedBlock#updateCachedStorageInfo}
* to update the cached Storage ID/Type arrays.
* @param activeLen
*/
public void moveProvidedToEnd(int activeLen) {
if (activeLen <= 0) {
return;
}
// as this is a stable sort, for elements that are equal,
// the current order of the elements is maintained
Arrays.sort(locs, 0, (activeLen < locs.length) ? activeLen : locs.length,
providedLastComparator);
}
public long getStartOffset() {
return offset;
}
public long getBlockSize() {
return b.getNumBytes();
}
public void setStartOffset(long value) {
this.offset = value;
}
public void setCorrupt(boolean corrupt) {
this.corrupt = corrupt;
}
public boolean isCorrupt() {
return this.corrupt;
}
/**
* Add a the location of a cached replica of the block.
*
* @param loc of datanode with the cached replica
*/
public void addCachedLoc(DatanodeInfo loc) {
List cachedList = Lists.newArrayList(cachedLocs);
if (cachedList.contains(loc)) {
return;
}
// Try to re-use a DatanodeInfo already in loc
for (DatanodeInfoWithStorage di : locs) {
if (loc.equals(di)) {
cachedList.add(di);
cachedLocs = cachedList.toArray(cachedLocs);
return;
}
}
// Not present in loc, add it and go
cachedList.add(loc);
Preconditions.checkArgument(cachedLocs != EMPTY_LOCS,
"Cached locations should only be added when having a backing"
+ " disk replica!", loc, locs.length, Arrays.toString(locs));
cachedLocs = cachedList.toArray(cachedLocs);
}
/**
* @return Datanodes with a cached block replica
*/
public DatanodeInfo[] getCachedLocations() {
return cachedLocs;
}
@Override
public String toString() {
return getClass().getSimpleName() + "{" + b
+ "; getBlockSize()=" + getBlockSize()
+ "; corrupt=" + corrupt
+ "; offset=" + offset
+ "; locs=" + Arrays.asList(locs)
+ "}";
}
public boolean isStriped() {
return false;
}
public BlockType getBlockType() {
return BlockType.CONTIGUOUS;
}
}
