lock.java

一个工作流设计及定义的系统,可以直接与数据库结合进行系统工作流程的定义及应用.

/*
 * Copyright (c) 2005, John Mettraux, OpenWFE.org
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * 
 * . Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.  
 * 
 * . Redistributions in binary form must reproduce the above copyright notice, 
 *   this list of conditions and the following disclaimer in the documentation 
 *   and/or other materials provided with the distribution.
 * 
 * . Neither the name of the "OpenWFE" nor the names of its contributors may be
 *   used to endorse or promote products derived from this software without
 *   specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * $Id: Lock.java,v 1.3 2005/05/17 16:41:05 jmettraux Exp $
 */

//
// Lock.java
//
// [e-mail]
//
// generated with 
// jtmpl 1.1.01 2004/05/19 ([e-mail])
//

package openwfe.org.worklist.store;

import javax.security.auth.Subject;


/**
 * This class is used to keep track of locks on workitems, those locks
 * prevent concurrent modifications on workitems.
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Id: Lock.java,v 1.3 2005/05/17 16:41:05 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public class Lock
{

    /*
    private final static org.apache.log4j.Logger log = org.apache.log4j.Logger
        .getLogger(Lock.class.getName());
    */

    //
    // CONSTANTS & co

    //
    // FIELDS

    private Subject locker = null;
    private long lockTimeout = 0;
    private long lockTime = -1;

    //
    // CONSTRUCTORS

    public Lock (final Subject s, final long lockTimeout)
    {
        this.locker = s;
        this.lockTimeout = lockTimeout;
        touch();
    }

    //
    // METHODS

    public Subject getLocker () { return this.locker; }

    public boolean shouldBeUnlocked ()
    {
        long delta = System.currentTimeMillis() - this.lockTime;

        return (delta > this.lockTimeout);
    }

    public void touch ()
    {
        this.lockTime = System.currentTimeMillis();
    }

    //
    // STATIC METHODS

}