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     */
018    package org.apache.oozie.command;
019    
020    import 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     */
030    public 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    }