/**
 * Copyright (c) 2010 Yahoo! Inc. All rights reserved.
 * Licensed 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. See accompanying LICENSE file.
 */
package org.apache.oozie.command;

import org.apache.oozie.client.Job;
import org.apache.oozie.util.ParamChecker;

/**
 * This is the base commands for all the jobs related commands . This will drive the statuses for all the jobs and all
 * the jobs will follow the same state machine.
 *
 * @param <T>
 */
public abstract class TransitionXCommand<T> extends XCommand<T> {

    protected Job job;

    public TransitionXCommand(String name, String type, int priority) {
        super(name, type, priority);
    }

    public TransitionXCommand(String name, String type, int priority, boolean dryrun) {
        super(name, type, priority, dryrun);
    }

    /**
     * Transit to the next status based on the result of the Job.
     *
     * @throws CommandException
     */
    public abstract void transitToNext() throws CommandException;

    /**
     * Update the parent job.
     *
     * @throws CommandException
     */
    public abstract void updateJob() throws CommandException;

    /**
     * This will be used to notify the parent about the status of that perticular job.
     *
     * @throws CommandException
     */
    public abstract void notifyParent() throws CommandException;

    /* (non-Javadoc)
     * @see org.apache.oozie.command.XCommand#execute()
     */
    @Override
    protected T execute() throws CommandException {
        transitToNext();
        updateJob();
        notifyParent();
        return null;
    }

    /**
     * Get the Job for the command.
     *
     * @return the job
     */
    public Job getJob() {
        return job;
    }

    /**
     * Set the Job for the command.
     *
     * @param job the job
     */
    public void setJob(Job job) {
        this.job = ParamChecker.notNull(job, "job");
    }

}