concurrentflowexpression.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: ConcurrentFlowExpression.java,v 1.12 2005/07/26 20:54:47 jmettraux Exp $
 */

//
// ConcurrentFlowExpression.java
//
// [e-mail]
//
// generated with 
// jtmpl 1.0.04 31.10.2002 John Mettraux ([e-mail])
//

package openwfe.org.engine.expressions;

import openwfe.org.ApplicationContext;
import openwfe.org.engine.Definitions;
import openwfe.org.engine.workitem.InFlowWorkItem;
import openwfe.org.engine.expressions.sync.SyncUtils;
import openwfe.org.engine.expressions.sync.SyncExpression;
import openwfe.org.engine.expressions.sync.SynchableExpression;


/**
 * The basic abstract class for expressions that launches their children 
 * concurrently
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Date: 2005/07/26 20:54:47 $
 * <br>$Id: ConcurrentFlowExpression.java,v 1.12 2005/07/26 20:54:47 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public abstract class ConcurrentFlowExpression

    extends AbstractCompositeFlowExpression

    implements SynchableExpression
    
{

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

    //
    // FIELDS

    private SyncExpression syncExpression = null;

    //
    // CONSTRUCTORS

    //
    // BEAN METHODS

    //
    // METHODS

    //
    // METHODS from SynchableExpression

    public SyncExpression getSyncExpression () 
    { 
        return this.syncExpression; 
    }

    public void setSyncExpression (final SyncExpression se) 
    { 
        //log.debug("setSyncExpression() "+se.getClass());

        this.syncExpression = se;
    }

    //
    // METHODS from FlowExpression

    /**
     * Replacing a child with another expression (overrides method
     * as found in AbstractCompositeFlowExpression).
     */
    public boolean replaceChild 
        (final FlowExpressionId thisFei, final FlowExpressionId thatFei)
    {
        return
            super.replaceChild(thisFei, thatFei) &&
            getSyncExpression().replaceChild(thisFei, thatFei);
    }

    public void apply (final InFlowWorkItem wi) 
        throws ApplyException
    {

        if (getChildren() == null || getChildren().size() < 1)
        {
            log.debug("No children to throw, replying to parent expression");

            try
            {
                replyToParent(wi);
            }
            catch (ReplyException re)
            {
                throw new ApplyException
                    ("Failed to reply to parent of empty "+
                     "concurrent flow expression", re);
            }

            return;
        }

        //
        // determine sync expression

        log.debug("apply() setting syncExpression");

        this.setSyncExpression
            (SyncUtils.determineSyncExpression(this, getChildren(), wi));

        //
        // run this concurrence stuff

        synchronized (this)
        {
            int i;

            for (i = 0; i < getChildren().size(); i++)
            {
                final FlowExpressionId child = 
                    (FlowExpressionId)getChildren().get(i);

                getSyncExpression().addChild(child);
            }

            for (i = 0; i < getChildren().size(); i++)
            {
                final FlowExpressionId child = 
                    (FlowExpressionId)getChildren().get(i);

                getExpressionPool().apply(child, wi);
                    // NB : child will reply to sync expression
            }

            this.storeItself();
        }
    }

}