001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 * 
010 *      http://www.apache.org/licenses/LICENSE-2.0
011 * 
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.oozie.command;
019
020import org.apache.oozie.client.Job;
021
022/**
023 * Transition command for start the job. The derived class has to override these following functions:
024 * <p/>
025 * loadState() : load the job's and/or actions' state
026 * updateJob() : update job status and attributes
027 * StartChildren() : submit or queue commands to start children
028 * notifyParent() : update the status to upstream if any
029 */
030public abstract class StartTransitionXCommand extends TransitionXCommand<Void> {
031
032    /**
033     * The constructor for abstract class {@link StartTransitionXCommand}
034     *
035     * @param name the command name
036     * @param type the command type
037     * @param priority the command priority
038     */
039    public StartTransitionXCommand(String name, String type, int priority) {
040        super(name, type, priority);
041    }
042
043    /**
044     * The constructor for abstract class {@link StartTransitionXCommand}
045     *
046     * @param name the command name
047     * @param type the command type
048     * @param priority the command priority
049     * @param dryrun true if dryrun is enable
050     */
051    public StartTransitionXCommand(String name, String type, int priority, boolean dryrun) {
052        super(name, type, priority, dryrun);
053    }
054
055    /**
056     * Start actions associated with the job
057     *
058     * @throws CommandException thrown if failed to start actions
059     */
060    public abstract void StartChildren() throws CommandException;
061
062    /* (non-Javadoc)
063     * @see org.apache.oozie.command.TransitionXCommand#transitToNext()
064     */
065    @Override
066    public final void transitToNext() {
067        if (job == null) {
068            job = this.getJob();
069        }
070        job.setStatus(Job.Status.RUNNING);
071        job.setPending();
072    }
073
074    /* (non-Javadoc)
075     * @see org.apache.oozie.command.TransitionXCommand#execute()
076     */
077    @Override
078    protected Void execute() throws CommandException {
079        transitToNext();
080        updateJob();
081        StartChildren();
082        performWrites();
083        notifyParent();
084        return null;
085    }
086}