Queue.java

/**
 * 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.mapred;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.security.authorize.AccessControlList;
import org.apache.hadoop.util.StringUtils;

/**
 * A class for storing the properties of a job queue.
 */
class Queue {

  private static final Log LOG = LogFactory.getLog(Queue.class);

  private String name;
  private Map<String,AccessControlList> acls;
  private QueueState state = QueueState.RUNNING;
  private QueueMetrics queueMetrics;

  /**
   * An Object that can be used by schedulers to fill in
   * arbitrary scheduling information. The toString method
   * of these objects will be called by the framework to
   * get a String that can be displayed on UI.
   */
  private Object schedulingInfo;

  /**
   * Enum representing queue state
   */
  static enum QueueState {
    STOPPED("stopped"), RUNNING("running");

    private final String stateName;

    QueueState(String stateName) {
      this.stateName = stateName;
    }

    public String getStateName() {
      return stateName;
    }
  }

  /**
   * Create a job queue
   * @param name name of the queue
   * @param acls ACLs for the queue
   * @param state state of the queue
   */
  Queue(String name, Map<String, AccessControlList> acls, QueueState state,
        QueueMetrics metrics) {
	  this.name = name;
	  this.acls = acls;
	  this.state = state;
	  this.queueMetrics = metrics;
  }

  /**
   * Return the name of the queue
   *
   * @return name of the queue
   */
  String getName() {
    return name;
  }

  /**
   * Set the name of the queue
   * @param name name of the queue
   */
  void setName(String name) {
    assert name != null;
    this.name = name;
  }

  /**
   * Return the ACLs for the queue
   *
   * The keys in the map indicate the operations that can be performed,
   * and the values indicate the list of users/groups who can perform
   * the operation.
   *
   * @return Map containing the operations that can be performed and
   *          who can perform the operations.
   */
  Map<String, AccessControlList> getAcls() {
    return acls;
  }

  /**
   * Set the ACLs for the queue
   * @param acls Map containing the operations that can be performed and
   *          who can perform the operations.
   */
  void setAcls(Map<String, AccessControlList> acls) {
    assert acls != null;
    this.acls = acls;
  }

  /**
   * Return the state of the queue.
   * @return state of the queue
   */
  QueueState getState() {
    return state;
  }

  /**
   * Set the state of the queue.
   * @param state state of the queue.
   */
  void setState(QueueState state) {
    assert state != null;
    this.state = state;
  }

  /**
   * Return the scheduling information for the queue
   * @return scheduling information for the queue.
   */
  Object getSchedulingInfo() {
    return schedulingInfo;
  }

  /**
   * Set the scheduling information from the queue.
   * @param schedulingInfo scheduling information for the queue.
   */
  void setSchedulingInfo(Object schedulingInfo) {
    this.schedulingInfo = schedulingInfo;
  }

  /**
   * Return the QueueMetrics object for this queue
   * @return QueueMetrics
   */
  public QueueMetrics getMetrics() {
    return this.queueMetrics;
  }
}