zkoss/zk

/* Threads.java

    Purpose:
        
    Description:
        
    History:
        Sat Feb 21 23:12:06     2004, Created by tomyeh

Copyright (C) 2003 Potix Corporation. All Rights Reserved.

{{IS_RIGHT
    This program is distributed under LGPL Version 2.1 in the hope that
    it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.lang;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Thread relevant utilities.
 *
 * @author tomyeh
 */
public class Threads {
    private static final Logger log = LoggerFactory.getLogger(Threads.class);

    /** Put the current thread to sleep for a while.
     * @exception SystemException if it is interrupted.
     * @since 3.0.0
     */
    public static final void sleep(int millisecs) {
        try {
            Thread.sleep(millisecs);
        } catch (InterruptedException ex) {
            throw SystemException.Aide.wrap(ex);
        }
    }

    /** Sets the priority without throwing any exception but log warning.
     */
    public static final void setPriority(Thread thd, int priority) {
        try {
            thd.setPriority(priority);
        }catch(Exception ex) {
            log.warn("Unable to change priority to "+priority, ex);
        }
    }
    /** Sets the priority without throwing any exception but log warning.
     */
    public static final void setDaemon(Thread thd, boolean daemon) {
        try {
            thd.setDaemon(daemon);
        }catch(Exception ex) {
            log.warn("Unable to set DAEMON", ex);
        }
    }

    /** Waits a thread to die (and interrupt once a while)
     * @param timeout how long to wait (0 means forever)
     */
    public static final void joinAndInterrupt(Thread thd, int timeout)
    throws InterruptedException {
        if (timeout == 0)
            timeout = Integer.MAX_VALUE;

        final int PERIOD = 5000; //5 secs
        for (int j = 0; timeout > 0; timeout -= PERIOD) {
            thd.join(timeout > PERIOD ? PERIOD: timeout);
            if (!thd.isAlive())
                return; //done;

            try {
                thd.interrupt(); //just in case
            } catch (Throwable e2) { //ignore it
            }

            if ((++j & 0x7) == 0)
                log.info("Wait another thread to die over "+j*PERIOD/1000+" seconds");
        }
    }

    /** A dummy function that is used to avoid compiler from optimizing
     * statements around it.
     */
    public static final void dummy(Object o) {
        new Integer(Objects.hashCode(o));
    }
}