abstractworkitemdispatcher.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: AbstractWorkItemDispatcher.java,v 1.7 2005/05/17 16:40:22 jmettraux Exp $
 */

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

package openwfe.org.engine.dispatch;

import openwfe.org.MapUtils;
import openwfe.org.AbstractService;
import openwfe.org.ServiceException;
import openwfe.org.ApplicationContext;
import openwfe.org.engine.Definitions;
import openwfe.org.engine.listen.reply.OkReply;
import openwfe.org.engine.listen.reply.FatalReply;
import openwfe.org.engine.listen.reply.WarningReply;
import openwfe.org.engine.listen.reply.ListenerReply;
import openwfe.org.engine.workitem.WorkItemCoder;
import openwfe.org.engine.workitem.WorkItemCoderLoader;


/**
 * Half an implementation of a WorkItemDispatcher
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Date: 2005/05/17 16:40:22 $
 * <br>$Id: AbstractWorkItemDispatcher.java,v 1.7 2005/05/17 16:40:22 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public abstract class AbstractWorkItemDispatcher

    extends AbstractService

    implements WorkItemDispatcher

{

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

    //
    // CONSTANTS (definitions)

    /**
     * This init param (named 'workItemCoder') is used to set the workitem
     * coder used by this workitem dispatcher.
     */
    public final static String WORKITEM_CODER
        = "workItemCoder";

    //
    // FIELDS

    private String workItemCoderName = null;

    //
    // CONSTRUCTORS

    /**
     * The required initialized method of a service.
     */
    public void init 
        (final String serviceName, 
         final ApplicationContext context, 
         final java.util.Map serviceParams)
    throws 
        ServiceException
    {
        super.init(serviceName, context, serviceParams);

        //
        // get workItemCoder
        
        this.workItemCoderName = MapUtils.getAsString
            (getParams(), WORKITEM_CODER);

        // check it
        
        final WorkItemCoderLoader loader = 
            Definitions.getWorkItemCoderLoader(getContext());

        WorkItemCoder coder = loader.getCoder(this.workItemCoderName);
        if (coder == null) 
        {
            coder = loader.getDefaultCoder();

            log.info("using default coder");
        }

        this.workItemCoderName = coder.getName();

        //
        // that's all folks

        log.info
            ("Dispatcher '"+getName()+
             "' using coder '"+this.workItemCoderName+"'");
    }

    //
    // METHODS

    /**
     * Returns the name of workitem coder service that this dispatcher
     * has to use. If null is returned, it means that this service will
     * use the default workitem coder (as found in 
     * etc/engine/coder-configuratin.xml).
     */
    public String getWorkItemCoderName () 
    {
        return this.workItemCoderName;
    }

    /**
     * Internal usage : returns the workitem coder for usage.
     */
    protected WorkItemCoder instantiateEncoder ()
        throws DispatchingException
    {
        WorkItemCoderLoader coderLoader = Definitions
            .getWorkItemCoderLoader(getContext());

        WorkItemCoder coder = coderLoader.getDefaultCoder();

        if (this.workItemCoderName != null)
            coder = coderLoader.getCoder(this.workItemCoderName);

        return coder;
    }

    /**
     * This method is used by dispatcher implementations.
     * It will throw a dispatching exception if and only if the
     * reply is a fatal one.
     */
    protected Object handleReply (ListenerReply reply)
        throws DispatchingException
    {
        if (reply == null)
        {
            throw new DispatchingException("No reply from listener");
        }

        if (reply instanceof FatalReply)
        {
            throw new FatalDispatchingException((FatalReply)reply);
        }

        if (reply instanceof OkReply)
        {
            log.debug("Listener replied 'ok'");
            return ((OkReply)reply).getConsumerResult();
        }

        WarningReply warn = (WarningReply)reply;

        StringBuffer sb = new StringBuffer();
        sb.append("listener warned :\n");
        sb.append(warn.getMessage()); sb.append('\n');
        sb.append(warn.getExceptionMessage()); sb.append('\n');
        sb.append(warn.getExceptionStackTrace());

        log.warn(sb.toString());

        return null;
    }

}