SingleShell.java

/*
 ** Copyright [2012-2013] [Megam Systems]
 **
 ** 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.
 */
package org.megam.chef.shell;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.lang.ProcessBuilder.Redirect;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.RecursiveAction;
import java.util.concurrent.TimeUnit;

import org.megam.chef.core.Condition;
import org.megam.chef.exception.SourceException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.megam.chef.exception.ShellException;

/**
 * <p>SingleShell class.</p>
 *
 * @author rajthilak
 * @version $Id: $Id
 */
public class SingleShell extends RecursiveAction implements Stoppable {

	private MultiCommands cmd;
	private Logger logger = LoggerFactory.getLogger(SingleShell.class);
	private ProcessBuilder shellProc;

	/**
	 * <p>Constructor for SingleShell.</p>
	 *
	 * @param command a {@link org.megam.chef.shell.MultiCommands} object.
	 */
	public SingleShell(MultiCommands command) {
		this.cmd = command;
	}

	/**
	 * Processed the command using ProcessBuilder class Print the output's are
	 * wrote in the some file
	 */
	public void compute() {
		try {
			boolean stop_flag = false;
			Command prevCom = null;
			for (Iterator<Command> iter = cmd.getOrderedCommands().iterator(); iter
					.hasNext() && !stop_flag;) {
				Command com = iter.next();
				List<String> cmdList = new ArrayList<String>();
				cmdList = com.getCommandList();
				logger.debug("#-------------------------------------------------------#");
				logger.debug(cmdList.toString());
				logger.debug("#-------------------------------------------------------#");
				if (prevCom != null && prevCom.composable()) {
					prevCom.pipeto(null); // feed the previous pipe here.
					cmdList = com.pipeto(prevCom.appliedPlaceHolder());
				}
				if (cmdList != null) {
					shellProc = new ProcessBuilder(cmdList);
					shellProc.redirectOutput(Redirect.appendTo(com
							.getRedirectOutputFile()));
					shellProc.redirectError(Redirect.appendTo(com
							.getRedirectErrorFile()));
					Process p = shellProc.start();
					if (com.composable()) {
						int subrc = p.waitFor();
						if (subrc != 0) {
							stop_flag = true;
						}
						prevCom = com;
					}
				} else
					stop_flag = true;
			}
		} catch (IOException | InterruptedException | ShellException npe) {
			try {
				throw new ShellException(npe);
			} catch (ShellException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	/**
	 * <p>halt.</p>
	 */
	public void halt() {
		// do nothing for now, but we need to cancel the process that runs, and
		// start the
		// Rollback. Needs design in herk, to handle it.

	}

}