execrunner.java

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//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc.  All rights reserved.
// OpenNMS(R) is a derivative work, containing both original code, included code and modified
// code that was published under the GNU General Public License. Copyrights for modified 
// and included code are below.
//
// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
//
// For more information contact: 
//      OpenNMS Licensing       <[e-mail]>
//      http://www.opennms.org/
//      http://www.opennms.com/
//
package org.opennms.netmgt.utils;

////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2002  Scott McCrory
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
////////////////////////////////////////////////////////////////////////////////

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Date;
import java.util.StringTokenizer;

/**
 * <P>
 * Runs external executables, optionally under a watched thread.
 * 
 * In addition, probably the most useful feature of ExecRunner is using it to
 * run a command-line program and obtain its stdout and stderr results in two
 * strings. This is done with exec(String) - see that method for an example.
 * 
 * With acknowledgements to Michael C. Daconta, author of "Java Pitfalls, Time
 * Saving Solutions, and Workarounds to Improve Programs." and his article in
 * JavaWorld "When Runtime.exec() Won't".
 * </P>
 * 
 * @author <a href="mailto:[e-mail]">Scott McCrory </a>.
 * @version CVS $Id: ExecRunner.java 1199 2004-11-21 03:31:16Z brozow $
 */
public class ExecRunner {

    /** Win NT/2K/MEPro require cmd.exe to run programs * */
    private static final String WINDOWS_NT_2000_COMMAND_1 = "cmd.exe";

    /** Win NT/2K/MEPro require the /C to specify what to run * */
    private static final String WINDOWS_NT_2000_COMMAND_2 = "/C";

    /** Win 9X/MEHome require cmd.exe to run programs * */
    private static final String WINDOWS_9X_ME_COMMAND_1 = "command.exe";

    /** Win 9X/MEHome require the /C to specify what to run * */
    private static final String WINDOWS_9X_ME_COMMAND_2 = "/C";

    /** String to send to STDERR if program exceeds max run time * */
    private static final String MAX_RUN_TIME_EXCEEDED_STRING = "MAX_RUN_TIME_EXCEEDED";

    /** String to capture STDOUT * */
    private String out = new String();

    /** String to capture STDERR * */
    private String err = new String();

    /** Default max run time (in seconds) * */
    private int maxRunTimeSecs = 0;

    /** Flag to indicate if we've exceeded max run time * */
    private boolean maxRunTimeExceeded = false;

    /** The name of this class for logging * */
    private static final String CLASS_NAME = "ExecRunner";

    /** The version of this class (filled in by CVS) * */
    private static final String VERSION = "CVS $Revision: 1199 $";

    /** Number of miliseconds to wait between polling watched thread * */
    private static final int POLL_DELAY_MS = 100;

    /**
     * Basic ExecRunner constructor.
     * 
     */
    public ExecRunner() {
        super();
    }

    /**
     * ExecRunner constructor which also conveniently runs exec(String).
     * 
     * @param command
     *            The program or command to run
     * @throws ExceptionInInitializerError
     *             thrown if a problem occurs
     */
    public ExecRunner(String command) throws ExceptionInInitializerError {
        this();
        try {
            exec(command);
        } catch (IOException ioe) {
            throw new ExceptionInInitializerError(ioe.getMessage());
        } catch (InterruptedException inte) {
            throw new ExceptionInInitializerError(inte.getMessage());
        }

    }

    /**
     * We override the <code>clone</code> method here to prevent cloning of
     * our class.
     * 
     * @throws CloneNotSupportedException
     *             To indicate cloning is not allowed
     * @return Nothing ever really returned since we throw a
     *         CloneNotSupportedException
     */
    public final Object clone() throws CloneNotSupportedException {

        throw new java.lang.CloneNotSupportedException();

    }

    /**
     * The <B>exec(String) </B> method runs a process inside of a watched
     * thread. It returns the client's exit code and feeds its STDOUT and STDERR
     * to ExecRunner's out and err strings, where you then use getOutString()
     * and getErrString() to obtain these values. Example:
     * 
     * <pre>
     * 
     * // Execute the program and grab the results
     * try {
     *     ExecRunner er = new ExecRunner();
     *     er.setMaxRunTimeSecs(5);
     *     er.exec(&quot;ls -l&quot;);
     *     if (!er.getMaxRunTimeExceeded()) {
     *         out = er.getOutString();
     *         err = er.getErrString();
     *     } else {
     *         System.out.println(&quot;Maximum run time exceeded!&quot;);
     *     }
     * } catch (Exception e) {
     *     System.out.println(&quot;Error executing &quot; + program + &quot;: &quot; + e.getMessage());
     *     continue;
     * }
     * </pre>
     * 
     * @return The command's return code
     * @param command
     *            The program or command to run
     * @throws IOException
     *             thrown if a problem occurs
     * @throws InterruptedException
     *             thrown if a problem occurs
     */
    public int exec(String command) throws IOException, InterruptedException {

        StringWriter swOut = new StringWriter();
        PrintWriter pwOut = new PrintWriter(swOut, true);

        StringWriter swErr = new StringWriter();
        PrintWriter pwErr = new PrintWriter(swErr, true);

        int rc = exec(command, pwOut, pwErr);

        out = swOut.toString();
        err = swErr.toString();

        return rc;

    }

    /**
     * Convenience method for calling exec with OutputStreams.
     * 
     * @return The command's return code
     * @param command
     *            The program or command to run
     * @param stdoutStream
     *            java.io.OutputStream
     * @param stderrStream
     *            java.io.OutputStream
     * @throws IOException
     *             thrown if a problem occurs
     * @throws InterruptedException
     *             thrown if a problem occurs
     */
    public int exec(String command, OutputStream stdoutStream, OutputStream stderrStream) throws IOException, InterruptedException {

        PrintWriter pwOut = new PrintWriter(stdoutStream, true);
        PrintWriter pwErr = new PrintWriter(stderrStream, true);

        return exec(command, pwOut, pwErr);

    }

    /**
     * The <code>exec(String, PrintWriter, PrintWriter)</code> method runs a
     * process inside of a watched thread. It returns the client's exit code and
     * feeds its STDOUT and STDERR to the passed-in streams.
     * 
     * @return The command's return code
     * @param command
     *            The program or command to run
     * @param stdoutWriter
     *            java.io.PrintWriter
     * @param stderrWriter
     *            java.io.PrintWriter
     * @throws IOException
     *             thrown if a problem occurs
     * @throws InterruptedException
     *             thrown if a problem occurs
     */
    public int exec(String command, PrintWriter stdoutWriter, PrintWriter stderrWriter) throws IOException, InterruptedException {