LoadManager.java
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上传日期:2018-01-08
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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.mapred;
- import java.io.IOException;
- import org.apache.hadoop.conf.Configurable;
- import org.apache.hadoop.conf.Configuration;
- /**
- * A pluggable object that manages the load on each {@link TaskTracker}, telling
- * the {@link TaskScheduler} when it can launch new tasks.
- */
- public abstract class LoadManager implements Configurable {
- protected Configuration conf;
- protected TaskTrackerManager taskTrackerManager;
-
- public Configuration getConf() {
- return conf;
- }
- public void setConf(Configuration conf) {
- this.conf = conf;
- }
- public synchronized void setTaskTrackerManager(
- TaskTrackerManager taskTrackerManager) {
- this.taskTrackerManager = taskTrackerManager;
- }
-
- /**
- * Lifecycle method to allow the LoadManager to start any work in separate
- * threads.
- */
- public void start() throws IOException {
- // do nothing
- }
-
- /**
- * Lifecycle method to allow the LoadManager to stop any work it is doing.
- */
- public void terminate() throws IOException {
- // do nothing
- }
-
- /**
- * Can a given {@link TaskTracker} run another map task?
- * @param tracker The machine we wish to run a new map on
- * @param totalRunnableMaps Set of running jobs in the cluster
- * @param totalMapSlots The total number of map slots in the cluster
- * @return true if another map can be launched on <code>tracker</code>
- */
- public abstract boolean canAssignMap(TaskTrackerStatus tracker,
- int totalRunnableMaps, int totalMapSlots);
- /**
- * Can a given {@link TaskTracker} run another reduce task?
- * @param tracker The machine we wish to run a new map on
- * @param totalRunnableReduces Set of running jobs in the cluster
- * @param totalReduceSlots The total number of reduce slots in the cluster
- * @return true if another reduce can be launched on <code>tracker</code>
- */
- public abstract boolean canAssignReduce(TaskTrackerStatus tracker,
- int totalRunnableReduces, int totalReduceSlots);
- }