caseexpression.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: CaseExpression.java,v 1.8 2005/05/17 16:40:23 jmettraux Exp $
 */

//
// CaseExpression.java
//
// [e-mail]
//
// generated with 
// jtmpl 1.0.04 20.11.2001 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.map.ExpressionMap;


/**
 * The cond expression is almost exactly the translation of the Scheme 'cond'.
 * It's a kind of multi-if.
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Date: 2005/05/17 16:40:23 $
 * <br>$Id: CaseExpression.java,v 1.8 2005/05/17 16:40:23 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public class CaseExpression

    extends IfExpression

{

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

    //
    // FIELDS

    private int currentId = -1;

    //
    // CONSTRUCTORS

    //
    // BEAN METHODS

    public int getCurrentId () { return this.currentId; }

    public void setCurrentId (final int i) { this.currentId = i; }

    //
    // METHODS

    public void apply (final InFlowWorkItem wi) 
        throws ApplyException
    {
        log.debug("apply()");

        if (getChildren() == null || getChildren().size() < 1)
        {
            try
            {
                replyToParent(wi);
            }
            catch (ReplyException re)
            {
                throw new ApplyException
                    ("Failed to reply to parent expression", re);
            }
            return;
        }

        setCurrentId(0);

        this.storeItself();

        getExpressionPool().apply
            ((FlowExpressionId)getChildren().get(getCurrentId()), wi);
    }

    public void reply (final InFlowWorkItem wi)
        throws ReplyException
    {
        //log.debug("reply()");

        if (isConditionTreated())
        {
            log.debug("reply() case solved.");

            replyToParent(wi);
            return;
        }

        log.debug
            ("reply()"+
             " expressionId is "+getId().getExpressionId()+
             ", currentId is "+getCurrentId()+
             ", children.size() is "+getChildren().size());

        if (getCurrentId()+1 >= getChildren().size())
        {
            log.debug("reply() no more children, replying to parent.");

            replyToParent(wi);
            return;
        }

        final boolean booleanResult = lookupLocalBooleanResult();

        if (booleanResult)
            //
            // eval next (if present)
        {
            this.setConditionTreated(true);

            setCurrentId(getCurrentId()+1);
        }
        else
            //
            // else : eval next+1
        {
            if (getCurrentId()+2 >= getChildren().size())
            {
                
                log.debug("reply() no over next child, replying to parent.");

                replyToParent(wi);
                return;
            }

            setCurrentId(getCurrentId()+2);
        }

        this.storeItself();

        try
        {
            log.debug("reply() eval child index "+getCurrentId());

            getExpressionPool().apply
                ((FlowExpressionId)getChildren().get(getCurrentId()), wi);
        }
        catch (final ApplyException ae)
        {
            throw new ReplyException
                ("Failed to apply child expression at index "+getCurrentId(), 
                 ae);
        }
    }

    /* *
     * A droflo oriented method, allows a workflow
     * definition to be saved as XML...
     * /
    public org.jdom.Element outputAsXml 
        (final ApplicationContext context, 
         final ProcessDefinition definition, 
         final org.jdom.Element containerElement)
    {
        final ExpressionMap exMap = Definitions.getExpressionMap(context);

        org.jdom.Element result = 
            new org.jdom.Element(exMap.getName(this.getClass()));

        openwfe.org.Utils.setAttributes(result, this.getAttributes());

        for (int i=0; i<getChildren().size(); i++)
        {
            if (i < getChildren().size()-1)
            {
                if (i % 2 == 0)
                    result.addContent(new org.jdom.Comment("if"));
                else
                    result.addContent(new org.jdom.Comment("then"));
            }
            else
            {
                result.addContent(new org.jdom.Comment("else"));
            }

            result.addContent
                (getChild(activityDefinition, i)
                 .outputAsXml(context, activityDefinition, result));
        }

        return result;
    }
     */

}