org.gcaldaemon.core.file.CalendarReloader.java Source code

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Here is the source code for org.gcaldaemon.core.file.CalendarReloader.java

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//
// GCALDaemon is an OS-independent Java program that offers two-way
// synchronization between Google Calendar and various iCalalendar (RFC 2445)
// compatible calendar applications (Sunbird, Rainlendar, iCal, Lightning, etc).
//
// Apache License
// Version 2.0, January 2004
// http://www.apache.org/licenses/
// 
// Project home:
// http://gcaldaemon.sourceforge.net
//
package org.gcaldaemon.core.file;

import java.util.LinkedList;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.gcaldaemon.logger.QuickWriter;

/**
 * Calendar reloader thread.
 * 
 * Created: Jul 20, 2007 12:50:56 PM
 * 
 * @author Andras Berkes
 */
final class CalendarReloader extends Thread {

    // --- LOGGER ---

    protected static final Log log = LogFactory.getLog(CalendarReloader.class);

    // --- PARAMETERS ---

    private final String cmd;
    private final String[] args;

    private boolean locked = true;

    // --- CONSTRUCTOR ---

    CalendarReloader(String command) {
        cmd = command;
        args = parseLine(command);
        setPriority(MIN_PRIORITY);
        setDaemon(true);
    }

    // --- RELOAD/RESTART CALENDAR APPLICATION ---

    final synchronized void reload(boolean runOnce) {
        if (runOnce) {
            try {
                executeScript();
            } catch (Exception commandException) {
                log.warn("Unable to execute command (" + cmd + ")!", commandException);
            }
        } else {
            locked = false;
            notifyAll();
        }
    }

    // --- SCRIPT RUNNER LOOP ---

    public final void run() {
        for (;;) {
            try {

                // Wait for unlock
                synchronized (this) {
                    while (locked) {
                        wait(5000);
                    }
                    locked = true;
                }

                // Execute script
                executeScript();

            } catch (InterruptedException interrupt) {
                return;
            } catch (Exception commandException) {
                log.warn("Unable to execute command (" + cmd + ")!", commandException);
            }
        }
    }

    private final void executeScript() throws Exception {

        // Execute script
        log.debug("Executing reloader script (" + cmd + ")...");
        ProcessBuilder builder = new ProcessBuilder(args);
        Process script = builder.start();
        sleep(1000L);

        // Wait for script
        for (int i = 0; i < 15; i++) {
            try {
                script.exitValue();
            } catch (Exception processNotExited) {
                sleep(1000L);
            }
        }

        // Destroy script
        script.destroy();
        script = null;
        log.debug("Reloader script finished successfully.");
    }

    // --- COMMAND LINE PARSER ---

    /**
     * Splitting a string into a command-array.
     * 
     * <BR>
     * <BR>
     * word1 word2 word3 -> "word1", "word2", "word3" <BR>
     * word1 word2="word3 'abc' def" -> "word1", "word2", "word3 'abc' def" <BR>
     * 'wo"rd1'="word2" word3 -> "wo\"rd1", "word2", "word3" <BR>
     * etc.
     * 
     * @param cmdLine
     * @return String[]
     */
    private static final String[] parseLine(String cmdLine) {
        char delimiter = ' ';
        boolean inToken = false;
        QuickWriter writer = new QuickWriter(100);
        LinkedList tokens = new LinkedList();
        for (int i = 0; i < cmdLine.length(); i++) {
            char c = cmdLine.charAt(i);
            if (inToken) {
                if (c == delimiter || (delimiter == ' ' && c == '=')) {
                    tokens.add(writer.toString());
                    writer.flush();
                    if (c == '-') {
                        writer.write(c);
                    }
                    inToken = false;
                    continue;
                }
                writer.write(c);
            } else {
                if (c == '\'') {
                    delimiter = '\'';
                    inToken = true;
                } else {
                    if (c == '"') {
                        delimiter = '"';
                        inToken = true;
                    } else if (c == ' ') {

                        // Skip
                    } else {
                        delimiter = ' ';
                        writer.write(c);
                        inToken = true;
                    }
                }
            }
            if (i == cmdLine.length() - 1 && writer.length() != 0) {
                tokens.add(writer.toString());
            }
        }
        String[] array = new String[tokens.size()];
        tokens.toArray(array);
        return array;
    }

}