org.apache.hadoop.hdfs.server.blockmanagement.ReplicaUnderConstruction.java Source code

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Here is the source code for org.apache.hadoop.hdfs.server.blockmanagement.ReplicaUnderConstruction.java

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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.server.blockmanagement;

import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;

/**
 * ReplicaUnderConstruction contains information about replicas (or blocks
 * belonging to a block group) while they are under construction.
 *
 * The GS, the length and the state of the replica is as reported by the
 * datanode.
 *
 * It is not guaranteed, but expected, that datanodes actually have
 * corresponding replicas.
 */
class ReplicaUnderConstruction extends Block {
    private final DatanodeStorageInfo expectedLocation;
    private HdfsServerConstants.ReplicaState state;
    private boolean chosenAsPrimary;

    ReplicaUnderConstruction(Block block, DatanodeStorageInfo target, HdfsServerConstants.ReplicaState state) {
        super(block);
        this.expectedLocation = target;
        this.state = state;
        this.chosenAsPrimary = false;
    }

    /**
     * Expected block replica location as assigned when the block was allocated.
     * This defines the pipeline order.
     * It is not guaranteed, but expected, that the data-node actually has
     * the replica.
     */
    DatanodeStorageInfo getExpectedStorageLocation() {
        return expectedLocation;
    }

    /**
     * Get replica state as reported by the data-node.
     */
    HdfsServerConstants.ReplicaState getState() {
        return state;
    }

    /**
     * Whether the replica was chosen for recovery.
     */
    boolean getChosenAsPrimary() {
        return chosenAsPrimary;
    }

    /**
     * Set replica state.
     */
    void setState(HdfsServerConstants.ReplicaState s) {
        state = s;
    }

    /**
     * Set whether this replica was chosen for recovery.
     */
    void setChosenAsPrimary(boolean chosenAsPrimary) {
        this.chosenAsPrimary = chosenAsPrimary;
    }

    /**
     * Is data-node the replica belongs to alive.
     */
    boolean isAlive() {
        return expectedLocation.getDatanodeDescriptor().isAlive();
    }

    @Override // Block
    public int hashCode() {
        return super.hashCode();
    }

    @Override // Block
    public boolean equals(Object obj) {
        // Sufficient to rely on super's implementation
        return (this == obj) || super.equals(obj);
    }

    @Override
    public String toString() {
        final StringBuilder b = new StringBuilder(50);
        appendStringTo(b);
        return b.toString();
    }

    @Override
    public void appendStringTo(StringBuilder sb) {
        sb.append("ReplicaUC[").append(expectedLocation).append("|").append(state).append("]");
    }
}