org.apache.hadoop.hdfs.server.protocol.DatanodeStorage.java Source code

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Here is the source code for org.apache.hadoop.hdfs.server.protocol.DatanodeStorage.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.protocol;

import org.apache.hadoop.fs.StorageType;

import java.util.UUID;

/**
 * Class captures information of a storage in Datanode.
 */
public class DatanodeStorage {
    /** The state of the storage. */
    public enum State {
        NORMAL,

        /**
         * A storage that represents a read-only path to replicas stored on a shared
         * storage device. Replicas on {@link #READ_ONLY_SHARED} storage are not
         * counted towards live replicas.
         *
         * <p>
         * In certain implementations, a {@link #READ_ONLY_SHARED} storage may be
         * correlated to its {@link #NORMAL} counterpart using the
         * {@link DatanodeStorage#storageID}.  This property should be used for
         * debugging purposes only.
         * </p>
         */
        READ_ONLY_SHARED,

        FAILED
    }

    private final String storageID;
    private final State state;
    private final StorageType storageType;
    private static final String STORAGE_ID_PREFIX = "DS-";

    /**
     * Create a storage with {@link State#NORMAL} and {@link StorageType#DEFAULT}.
     */
    public DatanodeStorage(String storageID) {
        this(storageID, State.NORMAL, StorageType.DEFAULT);
    }

    public DatanodeStorage(String sid, State s, StorageType sm) {
        this.storageID = sid;
        this.state = s;
        this.storageType = sm;
    }

    public String getStorageID() {
        return storageID;
    }

    public State getState() {
        return state;
    }

    public StorageType getStorageType() {
        return storageType;
    }

    /**
     * Generate new storage ID. The format of this string can be changed
     * in the future without requiring that old storage IDs be updated.
     *
     * @return unique storage ID
     */
    public static String generateUuid() {
        return STORAGE_ID_PREFIX + UUID.randomUUID();
    }

    /**
     * Verify that a given string is a storage ID in the "DS-..uuid.." format.
     */
    public static boolean isValidStorageId(final String storageID) {
        try {
            // Attempt to parse the UUID.
            if (storageID != null && storageID.indexOf(STORAGE_ID_PREFIX) == 0) {
                UUID.fromString(storageID.substring(STORAGE_ID_PREFIX.length()));
                return true;
            }
        } catch (IllegalArgumentException ignored) {
        }

        return false;
    }

    @Override
    public String toString() {
        return "DatanodeStorage[" + storageID + "," + storageType + "," + state + "]";
    }

    @Override
    public boolean equals(Object other) {
        if (other == this) {
            return true;
        }

        if ((other == null) || !(other instanceof DatanodeStorage)) {
            return false;
        }
        DatanodeStorage otherStorage = (DatanodeStorage) other;
        return otherStorage.getStorageID().compareTo(getStorageID()) == 0;
    }

    @Override
    public int hashCode() {
        return getStorageID().hashCode();
    }
}