org.apache.hadoop.yarn.api.records.ApplicationId.java Source code

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Here is the source code for org.apache.hadoop.yarn.api.records.ApplicationId.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.yarn.api.records;

import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.classification.InterfaceStability.Stable;
import org.apache.hadoop.classification.InterfaceStability.Unstable;
import org.apache.hadoop.util.FastNumberFormat;
import org.apache.hadoop.yarn.util.Records;

/**
 * <p><code>ApplicationId</code> represents the <em>globally unique</em> 
 * identifier for an application.</p>
 * 
 * <p>The globally unique nature of the identifier is achieved by using the 
 * <em>cluster timestamp</em> i.e. start-time of the 
 * <code>ResourceManager</code> along with a monotonically increasing counter
 * for the application.</p>
 */
@Public
@Stable
public abstract class ApplicationId implements Comparable<ApplicationId> {

    @Private
    @Unstable
    public static final String appIdStrPrefix = "application";

    private static final String APPLICATION_ID_PREFIX = appIdStrPrefix + '_';

    @Public
    @Unstable
    public static ApplicationId newInstance(long clusterTimestamp, int id) {
        ApplicationId appId = Records.newRecord(ApplicationId.class);
        appId.setClusterTimestamp(clusterTimestamp);
        appId.setId(id);
        appId.build();
        return appId;
    }

    /**
     * Get the short integer identifier of the <code>ApplicationId</code>
     * which is unique for all applications started by a particular instance
     * of the <code>ResourceManager</code>.
     * @return short integer identifier of the <code>ApplicationId</code>
     */
    @Public
    @Stable
    public abstract int getId();

    @Private
    @Unstable
    protected abstract void setId(int id);

    /**
     * Get the <em>start time</em> of the <code>ResourceManager</code> which is 
     * used to generate globally unique <code>ApplicationId</code>.
     * @return <em>start time</em> of the <code>ResourceManager</code>
     */
    @Public
    @Stable
    public abstract long getClusterTimestamp();

    @Private
    @Unstable
    protected abstract void setClusterTimestamp(long clusterTimestamp);

    protected abstract void build();

    private static final int APP_ID_MIN_DIGITS = 4;

    @Override
    public int compareTo(ApplicationId other) {
        if (this.getClusterTimestamp() - other.getClusterTimestamp() == 0) {
            return this.getId() - other.getId();
        } else {
            return this.getClusterTimestamp() > other.getClusterTimestamp() ? 1
                    : this.getClusterTimestamp() < other.getClusterTimestamp() ? -1 : 0;
        }
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder(64);
        sb.append(APPLICATION_ID_PREFIX);
        sb.append(getClusterTimestamp());
        sb.append('_');
        FastNumberFormat.format(sb, getId(), APP_ID_MIN_DIGITS);
        return sb.toString();
    }

    @Public
    @Stable
    public static ApplicationId fromString(String appIdStr) {
        if (!appIdStr.startsWith(APPLICATION_ID_PREFIX)) {
            throw new IllegalArgumentException("Invalid ApplicationId prefix: " + appIdStr
                    + ". The valid ApplicationId should start with prefix " + appIdStrPrefix);
        }
        try {
            int pos1 = APPLICATION_ID_PREFIX.length() - 1;
            int pos2 = appIdStr.indexOf('_', pos1 + 1);
            if (pos2 < 0) {
                throw new IllegalArgumentException("Invalid ApplicationId: " + appIdStr);
            }
            long rmId = Long.parseLong(appIdStr.substring(pos1 + 1, pos2));
            int appId = Integer.parseInt(appIdStr.substring(pos2 + 1));
            ApplicationId applicationId = ApplicationId.newInstance(rmId, appId);
            return applicationId;
        } catch (NumberFormatException n) {
            throw new IllegalArgumentException("Invalid ApplicationId: " + appIdStr, n);
        }
    }

    @Override
    public int hashCode() {
        // Generated by eclipse.
        final int prime = 371237;
        int result = 6521;
        long clusterTimestamp = getClusterTimestamp();
        result = prime * result + (int) (clusterTimestamp ^ (clusterTimestamp >>> 32));
        result = prime * result + getId();
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        ApplicationId other = (ApplicationId) obj;
        if (this.getClusterTimestamp() != other.getClusterTimestamp())
            return false;
        if (this.getId() != other.getId())
            return false;
        return true;
    }
}