SysCommandExecutor.java

package org.molgenis.compute.sysexecutor;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class SysCommandExecutor
{
	private ILogDevice fOuputLogDevice = null;
	private ILogDevice fErrorLogDevice = null;
	private String fWorkingDirectory = null;
	private List fEnvironmentVarList = null;

	private StringBuffer fCmdOutput = null;
	private StringBuffer fCmdError = null;
	private AsyncStreamReader fCmdOutputThread = null;
	private AsyncStreamReader fCmdErrorThread = null;

	public void setOutputLogDevice(ILogDevice logDevice)
	{
		fOuputLogDevice = logDevice;
	}

	public void setErrorLogDevice(ILogDevice logDevice)
	{
		fErrorLogDevice = logDevice;
	}

	public void setWorkingDirectory(String workingDirectory)
	{
		fWorkingDirectory = workingDirectory;
	}

	public void setEnvironmentVar(String name, String value)
	{
		if (fEnvironmentVarList == null) fEnvironmentVarList = new ArrayList();

		fEnvironmentVarList.add(new EnvironmentVar(name, value));
	}

	public String getCommandOutput()
	{
		return fCmdOutput.toString();
	}

	public String getCommandError()
	{
		return fCmdError.toString();
	}

	public int runCommand(String commandLine) throws Exception
	{
		/* run command */
		Process process = runCommandHelper(commandLine);

		/* start output and error read threads */
		startOutputAndErrorReadThreads(process.getInputStream(), process.getErrorStream());

		/* wait for command execution to terminate */
		int exitStatus = -1;
		try
		{
			exitStatus = process.waitFor();

		}
		catch (Throwable ex)
		{
			throw new Exception(ex.getMessage());

		}
		finally
		{
			/* notify output and error read threads to stop reading */
			notifyOutputAndErrorReadThreadsToStopReading();
		}

		return exitStatus;
	}

	private Process runCommandHelper(String commandLine) throws IOException
	{
		Process process = null;
		if (fWorkingDirectory == null) process = Runtime.getRuntime().exec(commandLine, getEnvTokens());
		else
			process = Runtime.getRuntime().exec(commandLine, getEnvTokens(), new File(fWorkingDirectory));

		return process;
	}

	private void startOutputAndErrorReadThreads(InputStream processOut, InputStream processErr)
	{
		fCmdOutput = new StringBuffer();
		fCmdOutputThread = new AsyncStreamReader(processOut, fCmdOutput, fOuputLogDevice, "OUTPUT");
		fCmdOutputThread.start();

		fCmdError = new StringBuffer();
		fCmdErrorThread = new AsyncStreamReader(processErr, fCmdError, fErrorLogDevice, "ERROR");
		fCmdErrorThread.start();
	}

	private void notifyOutputAndErrorReadThreadsToStopReading()
	{
		fCmdOutputThread.stopReading();
		fCmdErrorThread.stopReading();
	}

	private String[] getEnvTokens()
	{
		if (fEnvironmentVarList == null) return null;

		String[] envTokenArray = new String[fEnvironmentVarList.size()];
		Iterator envVarIter = fEnvironmentVarList.iterator();
		int nEnvVarIndex = 0;
		while (envVarIter.hasNext() == true)
		{
			EnvironmentVar envVar = (EnvironmentVar) (envVarIter.next());
			String envVarToken = envVar.fName + "=" + envVar.fValue;
			envTokenArray[nEnvVarIndex++] = envVarToken;
		}

		return envTokenArray;
	}
}