TimeoutProcessBuilder.java

/*
 * TimeoutProcessBuilder
 *
 * $Id$
 * $URL$
 */
package gov.usgs.util;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Timer;
import java.util.TimerTask;

/**
 * The TimeoutProcessBuilder wraps a ProcessBuilder, adding support for a
 * command time out.
 *
 * This class does not support a full command String complete with arguments.
 * You can use the StringUtils.split method to get around this.
 *
 * @see java.lang.ProcessBuilder
 * @see TimeoutProcess
 */
public class TimeoutProcessBuilder {

    /** The wrapped process builder. */
    private ProcessBuilder builder = null;
    /** The timeout for this process. */
    private long timeout = -1;

    /**
     * Create a new TimeoutProcessBuilder with a timeout and an array of
     * strings.
     *
     * @param timeout
     *            timeout in milliseconds for process, or <= 0 for no timeout.
     * @param command
     *            array of strings that represent command. The first element
     *            must be the full path to the executable, without arguments.
     */
    public TimeoutProcessBuilder(long timeout, String... command) {
        builder = new ProcessBuilder(command);
        this.timeout = timeout;
    }

    /**
     * Create a new TimeoutProcessBuilder with a timeout and an array of
     * strings.
     *
     * @param timeout
     *            timeout in milliseconds for process, or <= 0 for no timeout.
     * @param command
     *            list of strings that represent command.
     */
    public TimeoutProcessBuilder(long timeout, List<String> command) {
        builder = new ProcessBuilder(command);
        this.timeout = timeout;

    }

    /**
     * This signature is preserved, but calls the alternate constructor with
     * argument order swapped.
     * @param command
     *            list of strings that represent command.
     * @param timeout
     *            timeout in milliseconds for process, or &lt;= 0 for no timeout.
     */
    @Deprecated
    public TimeoutProcessBuilder(List<String> command, long timeout) {
        this(timeout, command);
    }

    /** @return list of builder commands */
    public List<String> command() {
        return builder.command();
    }

    /**
     * @param command give builder a list of commands
     * @return TimeoutProcessBuilder
     */
    public TimeoutProcessBuilder command(List<String> command) {
        builder.command(command);
        return this;
    }

    /**
     * @param command give builder a single command
     * @return TimeoutProcessBuilder
     */
    public TimeoutProcessBuilder command(String command) {
        builder.command(command);
        return this;
    }

    /** @return builder directory */
    public File directory() {
        return builder.directory();
    }

    /**
     * @param directory to set
     * @return TimeoutProcessBuilder
     */
    public TimeoutProcessBuilder directory(File directory) {
        builder.directory(directory);
        return this;
    }

    /** @return builder environment */
    public Map<String, String> environment() {
        return builder.environment();
    }

    /** @return boolean redirectErrorStream */
    public boolean redirectErrorStream() {
        return builder.redirectErrorStream();
    }

    /**
     * @param redirectErrorStream to set
     * @return TimeoutProcessBuilder
     */
    public TimeoutProcessBuilder redirectErrorStream(boolean redirectErrorStream) {
        builder.redirectErrorStream(redirectErrorStream);
        return this;
    }

    /**
     * @return a TimeoutProcess
     * @throws IOException if IO error occurs
     */
    public TimeoutProcess start() throws IOException {
        final TimeoutProcess process = new TimeoutProcess(builder.start());

        if (timeout > 0) {
            // set up the timeout for this process
            final Timer timer = new Timer();
            timer.schedule(new TimerTask() {
                @Override
                public void run() {
                    process.setTimeoutElapsed(true);
                    process.destroy();
                }
            }, timeout);
            process.setTimer(timer);
        }

        return process;
    }

    /** @return timeout */
    public long getTimeout() {
        return this.timeout;
    }

    /** @param timeout to set */
    public void setTimeout(final long timeout) {
        this.timeout = timeout;
    }

}