| /** |
| * 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.server.namenode; |
| |
| import java.util.Arrays; |
| import java.util.LinkedList; |
| import java.util.List; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor; |
| import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.CachedBlocksList; |
| import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.CachedBlocksList.Type; |
| import org.apache.hadoop.util.IntrusiveCollection; |
| import org.apache.hadoop.util.LightWeightGSet; |
| import org.apache.hadoop.util.IntrusiveCollection.Element; |
| import org.apache.hadoop.util.LightWeightGSet.LinkedElement; |
| |
| /** |
| * Represents a cached block. |
| */ |
| @InterfaceAudience.LimitedPrivate({"HDFS"}) |
| public final class CachedBlock implements Element, |
| LightWeightGSet.LinkedElement { |
| private static final Object[] EMPTY_ARRAY = new Object[0]; |
| |
| /** |
| * Block id. |
| */ |
| private final long blockId; |
| |
| /** |
| * Used to implement #{LightWeightGSet.LinkedElement} |
| */ |
| private LinkedElement nextElement; |
| |
| /** |
| * Bit 15: Mark |
| * Bit 0-14: cache replication factor. |
| */ |
| private short replicationAndMark; |
| |
| /** |
| * Used to implement the CachedBlocksList. |
| * |
| * Since this CachedBlock can be in multiple CachedBlocksList objects, |
| * we need to be able to store multiple 'prev' and 'next' pointers. |
| * The triplets array does this. |
| * |
| * Each triplet contains a CachedBlockList object followed by a |
| * prev pointer, followed by a next pointer. |
| */ |
| private Object[] triplets; |
| |
| public CachedBlock(long blockId, short replication, boolean mark) { |
| this.blockId = blockId; |
| this.triplets = EMPTY_ARRAY; |
| setReplicationAndMark(replication, mark); |
| } |
| |
| public long getBlockId() { |
| return blockId; |
| } |
| |
| @Override |
| public int hashCode() { |
| return (int)(blockId^(blockId>>>32)); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (o == null) { return false; } |
| if (o == this) { return true; } |
| if (o.getClass() != this.getClass()) { |
| return false; |
| } |
| CachedBlock other = (CachedBlock)o; |
| return other.blockId == blockId; |
| } |
| |
| public void setReplicationAndMark(short replication, boolean mark) { |
| assert replication >= 0; |
| replicationAndMark = (short)((replication << 1) | (mark ? 0x1 : 0x0)); |
| } |
| |
| public boolean getMark() { |
| return ((replicationAndMark & 0x1) != 0); |
| } |
| |
| public short getReplication() { |
| return (short) (replicationAndMark >>> 1); |
| } |
| |
| /** |
| * Return true if this CachedBlock is present on the given list. |
| */ |
| public boolean isPresent(CachedBlocksList cachedBlocksList) { |
| for (int i = 0; i < triplets.length; i += 3) { |
| CachedBlocksList list = (CachedBlocksList)triplets[i]; |
| if (list == cachedBlocksList) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Get a list of the datanodes which this block is cached, |
| * planned to be cached, or planned to be uncached on. |
| * |
| * @param type If null, this parameter is ignored. |
| * If it is non-null, we match only datanodes which |
| * have it on this list. |
| * See {@link DatanodeDescriptor.CachedBlocksList.Type} |
| * for a description of all the lists. |
| * |
| * @return The list of datanodes. Modifying this list does not |
| * alter the state of the CachedBlock. |
| */ |
| public List<DatanodeDescriptor> getDatanodes(Type type) { |
| List<DatanodeDescriptor> nodes = new LinkedList<DatanodeDescriptor>(); |
| for (int i = 0; i < triplets.length; i += 3) { |
| CachedBlocksList list = (CachedBlocksList)triplets[i]; |
| if ((type == null) || (list.getType() == type)) { |
| nodes.add(list.getDatanode()); |
| } |
| } |
| return nodes; |
| } |
| |
| @Override |
| public void insertInternal(IntrusiveCollection<? extends Element> list, Element prev, |
| Element next) { |
| for (int i = 0; i < triplets.length; i += 3) { |
| if (triplets[i] == list) { |
| throw new RuntimeException("Trying to re-insert an element that " + |
| "is already in the list."); |
| } |
| } |
| Object newTriplets[] = Arrays.copyOf(triplets, triplets.length + 3); |
| newTriplets[triplets.length] = list; |
| newTriplets[triplets.length + 1] = prev; |
| newTriplets[triplets.length + 2] = next; |
| triplets = newTriplets; |
| } |
| |
| @Override |
| public void setPrev(IntrusiveCollection<? extends Element> list, Element prev) { |
| for (int i = 0; i < triplets.length; i += 3) { |
| if (triplets[i] == list) { |
| triplets[i + 1] = prev; |
| return; |
| } |
| } |
| throw new RuntimeException("Called setPrev on an element that wasn't " + |
| "in the list."); |
| } |
| |
| @Override |
| public void setNext(IntrusiveCollection<? extends Element> list, Element next) { |
| for (int i = 0; i < triplets.length; i += 3) { |
| if (triplets[i] == list) { |
| triplets[i + 2] = next; |
| return; |
| } |
| } |
| throw new RuntimeException("Called setNext on an element that wasn't " + |
| "in the list."); |
| } |
| |
| @Override |
| public void removeInternal(IntrusiveCollection<? extends Element> list) { |
| for (int i = 0; i < triplets.length; i += 3) { |
| if (triplets[i] == list) { |
| Object[] newTriplets = new Object[triplets.length - 3]; |
| System.arraycopy(triplets, 0, newTriplets, 0, i); |
| System.arraycopy(triplets, i + 3, newTriplets, i, |
| triplets.length - (i + 3)); |
| triplets = newTriplets; |
| return; |
| } |
| } |
| throw new RuntimeException("Called remove on an element that wasn't " + |
| "in the list."); |
| } |
| |
| @Override |
| public Element getPrev(IntrusiveCollection<? extends Element> list) { |
| for (int i = 0; i < triplets.length; i += 3) { |
| if (triplets[i] == list) { |
| return (Element)triplets[i + 1]; |
| } |
| } |
| throw new RuntimeException("Called getPrev on an element that wasn't " + |
| "in the list."); |
| } |
| |
| @Override |
| public Element getNext(IntrusiveCollection<? extends Element> list) { |
| for (int i = 0; i < triplets.length; i += 3) { |
| if (triplets[i] == list) { |
| return (Element)triplets[i + 2]; |
| } |
| } |
| throw new RuntimeException("Called getNext on an element that wasn't " + |
| "in the list."); |
| } |
| |
| @Override |
| public boolean isInList(IntrusiveCollection<? extends Element> list) { |
| for (int i = 0; i < triplets.length; i += 3) { |
| if (triplets[i] == list) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public String toString() { |
| return new StringBuilder().append("{"). |
| append("blockId=").append(blockId).append(", "). |
| append("replication=").append(getReplication()).append(", "). |
| append("mark=").append(getMark()).append("}"). |
| toString(); |
| } |
| |
| @Override // LightWeightGSet.LinkedElement |
| public void setNext(LinkedElement next) { |
| this.nextElement = next; |
| } |
| |
| @Override // LightWeightGSet.LinkedElement |
| public LinkedElement getNext() { |
| return nextElement; |
| } |
| } |