ProcessRunner.java

/* 
 * Kodkod -- Copyright (c) 2005-present, Emina Torlak
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package kodkod.test.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * A simple thread that runs a given command in a fresh process.
 * 
 * @specfield cmd: String[]
 * @author Emina Torlak
 */
public final class ProcessRunner extends Thread {
	private final String[] cmd;
	private Process process;
	
	/**
	 * Constructs a process runner for the given command.
	 * @ensures this.cmd' = cmd
	 */
	public ProcessRunner(String... cmd) { 
		this.cmd = cmd; 
		process =  null;
	}
	
	/**
	 * Destroys the process wrapped by this thread, if any.
	 * @ensures destroys the process wrapped by this thread, if any.
	 */
	public void destroyProcess() { if (process!=null) { process.destroy(); process=null; } }
	
	/**
	 * Gets the input stream of the subprocess running this.com. 
	 * The stream obtains data piped from the standard output stream 
	 * of the process run by this thread.
	 * @return input stream of the subprocess running this.com
	 */
	public InputStream processOutput() { 
		if (process==null) { 
			System.out.println("process not started.");
			throw new IllegalStateException();
		} else {
			return process.getInputStream();
		}
	}
	
	/**
	 * Gets the output stream of the subprocess running this.com. 
	 * The stream pipes data to the standard input stream 
	 * of the process run by this thread.
	 * @return output stream of the subprocess running this.com.
	 */
	public OutputStream processInput() {
		if (process==null) { 
			System.out.println("process not started.");
			throw new IllegalStateException();
		} else {
			return process.getOutputStream();
		}
	}
	
	/**
	 * Gets the error stream of the subprocess running this.com. 
	 * The stream obtains data piped from the standard error stream 
	 * of the process run by this thread.
	 * @return error stream of the subprocess running this.com
	 */
	public InputStream processError() { 
		if (process==null) { 
			System.out.println("process not started.");
			throw new IllegalStateException();
		} else {
			return process.getErrorStream();
		}
	}
	
	/**
	 * Starts and waits for a process that runs this.cmd
	 * @see java.lang.Thread#run()
	 */
	public void run() { 
		try {
			process =  Runtime.getRuntime().exec(cmd) ;
			process.waitFor();
		} catch (IOException e) {
			System.out.print("Could not run: ");
			for(String c: cmd) { 
				System.out.print(c + " ");
			}
			System.out.println();
			System.exit(1);
		} catch (InterruptedException e) {
			// ignore
		}
	}
}