frozenstate.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: FrozenState.java,v 1.4 2005/05/17 16:40:25 jmettraux Exp $
 */

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

package openwfe.org.engine.expressions.state;

import openwfe.org.engine.expool.ExpressionPool;
import openwfe.org.engine.workitem.InFlowWorkItem;
import openwfe.org.engine.expressions.FlowExpression;
import openwfe.org.engine.expressions.ApplyException;
import openwfe.org.engine.expressions.ReplyException;


/**
 * A paused expression will be transparent, the flow will run trough it as
 * if it was not here.
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Id: FrozenState.java,v 1.4 2005/05/17 16:40:25 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public class FrozenState

    extends AbstractExpressionState

{

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

    //
    // CONSTANTS & co

    /**
     * A constant for [Text|Sql]History : "+FRZ"
     */
    public final static String EVT_FREEZE
        = "+FRZ";

    /**
     * A constant for [Text|Sql]History : "+UFZ"
     */
    public final static String EVT_UNFREEZE
        = "+UFZ";

    private final static String NAME = "frozen";
    private final static char IDENTIFIER = 'f';

    //
    // FIELDS

    private InFlowWorkItem appliedItem = null;

    private java.util.List replyQueue = null;

    //
    // CONSTRUCTORS

    //
    // BEAN METHODS

    /**
     * Returns a potential applied and thus frozen workitem
     */
    public InFlowWorkItem getAppliedItem () { return this.appliedItem; }

    /**
     * Returns the list of workitems that got successively replied to
     * the frozen expression.
     */
    public java.util.List getReplyQueue () { return this.replyQueue; }

    public void setAppliedItem (final InFlowWorkItem wi) 
    { 
        this.appliedItem = wi; 
    }

    public void setReplyQueue (final java.util.List rq)
    {
        this.replyQueue = rq;
    }

    //
    // METHODS from ExpressionState

    public String getName ()
    {
        return NAME;
    }

    /**
     * Returns a one char identifier for the state (for example 'f' for frozen)
     */
    public char getIdentifier ()
    {
        return IDENTIFIER;
    }

    public void apply (final InFlowWorkItem wi)
        throws ApplyException
    {
        if (this.appliedItem != null)
        {
            throw new ApplyException
                ("An expression should not get applied twice.");
        }

        this.appliedItem = (InFlowWorkItem)wi.clone();

        log.debug
            ("apply() applied item lastExpressionId : "+
             this.appliedItem.getLastExpressionId());
    }

    public void reply (final InFlowWorkItem wi)
        throws ReplyException
    {
        if (this.replyQueue == null)
            this.replyQueue = new java.util.LinkedList();

        this.replyQueue.add(wi);
    }

    public InFlowWorkItem cancel ()
        throws ApplyException
    {
        this.expression.cancel();

        return this.appliedItem;
            //
            // the applied item may be null, the replied items 
            // are not taken into account.
    }

    /**
     * Makes this expression leave this state.
     */
    public void exitState ()
        throws ApplyException
    {
        this.expression.setState(null);

        //this.expression.storeItself();
            //
            // should not be necessary as apply() or reply() will induce
            // it somehow

        if (this.replyQueue == null)
            //
            // apply
        {
            log.debug
                ("exitState() applying (exp) "+
                 this.expression.getId());
            log.debug
                ("exitState() applying (itm) "+
                 this.appliedItem.getLastExpressionId());

            this.expression.apply(this.appliedItem);
        }
        else
            //
            // reply
        {
            log.debug("exitState() replying to "+this.expression.getId());

            final java.util.Iterator it = this.replyQueue.iterator();
            while (it.hasNext())
            {
                final InFlowWorkItem wi = (InFlowWorkItem)it.next();

                try
                {
                    this.expression.reply(wi);
                }
                catch (final ReplyException re)
                {
                    log.warn
                        ("cancel() failure during 'reply' defreeze", re);
                }
            }
        }
    }

    //
    // STATIC METHODS

}