launchdispatcher.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: LaunchDispatcher.java,v 1.9 2005/05/17 16:40:22 jmettraux Exp $
 */

//
// LaunchDispatcher.java
//
// [e-mail]
//
// generated with 
// jtmpl 1.0.04 20.11.2001 John Mettraux ([e-mail])
//

package openwfe.org.engine.dispatch;

import openwfe.org.AbstractService;
import openwfe.org.ServiceException;
import openwfe.org.OpenWfeException;
import openwfe.org.ApplicationContext;
import openwfe.org.engine.Definitions;
import openwfe.org.engine.expool.ExpressionPool;
import openwfe.org.engine.workitem.Attribute;
import openwfe.org.engine.workitem.WorkItem;
import openwfe.org.engine.workitem.LaunchItem;
import openwfe.org.engine.workitem.InFlowWorkItem;
//import openwfe.org.engine.wfibuilder.WorkflowInstanceBuilder;
import openwfe.org.engine.expressions.ReplyException;
import openwfe.org.engine.expressions.FlowExpressionId;
import openwfe.org.engine.participants.ParticipantMap;
import openwfe.org.engine.participants.LeafParticipant;


/**
 * It dispatches workitems through sockets
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Date: 2005/05/17 16:40:22 $
 * <br>$Id: LaunchDispatcher.java,v 1.9 2005/05/17 16:40:22 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public class LaunchDispatcher

    extends AbstractService

    implements WorkItemDispatcher

{

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

    //
    // CONSTANTS (definitions)

    //
    // FIELDS

    private WorkItemDispatcher finalDispatcher = null;
    private boolean waitForResult = false;

    //
    // CONSTRUCTORS

    public LaunchDispatcher (WorkItemDispatcher finalDispatcher)
    {
        this.finalDispatcher = finalDispatcher;
    }

    public void init 
        (final String serviceName, 
         final ApplicationContext context, 
         final java.util.Map serviceParams)
    throws 
        ServiceException
    {
        super.init(serviceName, context, serviceParams);

        this.waitForResult = waitForResult
            (serviceParams.get(Definitions.WAIT_FOR_RESULT));
    }

    //
    // METHODS

    private boolean waitForResult (Object oWaitForResult)
    {
        if (oWaitForResult == null) return false;

        String sWaitForResult = oWaitForResult.toString();

        return ("yes".equalsIgnoreCase(sWaitForResult) ||
                "true".equalsIgnoreCase(sWaitForResult));
    }

    /*
     * When 'shouldWaitForResult' is set to false,
     * this method allows to directly continue the current flow
     */
    private void continueCurrentFlowDirectly (InFlowWorkItem wi)
        throws DispatchingException
    {
        FlowExpressionId id = wi.getLastExpressionId();

        try
        {
            Definitions
                .getExpressionPool(getContext())
                .reply(id, wi);
        }
        catch (ReplyException re)
        {
            throw new DispatchingException
                ("Failed to continue current flow directly", re);
        }

        log.debug
            ("Continued current flow directly for "+id);
    }

    /**
     * dispatches workitem (launches flow)
     */
    public Object dispatch (WorkItem wi) 
        throws DispatchingException
    {
        if (wi == null)
        {
            throw new DispatchingException
                ("Cannot handle null workitem !");
        }

        if ( ! (wi instanceof InFlowWorkItem))
        {
            throw new DispatchingException
                ("dispatching of LaunchItem instances not supported "+
                 "by this dispatcher");
        }

        InFlowWorkItem iwi = (InFlowWorkItem)wi;

        //
        // determine wf to launch
        //
        // precedence : wfd > pmap > wi
        
        // from wi

        String wfdUrl = null;

        Attribute aWfdUrl = 
            iwi.getAttribute(Definitions.WORKFLOW_DEFINITION_URL);

        if (aWfdUrl != null) 
            wfdUrl = aWfdUrl.toString();

        boolean shouldWaitForResult = waitForResult
            (wi.getAttribute(Definitions.WAIT_FOR_RESULT));

        // from pmap
        
        String participantName = 
            (String)getParams().get(LeafParticipant.PARTICIPANT_NAME);
        
        if (wfdUrl == null)
        {
            final ParticipantMap pMap = Definitions
                .getParticipantMap(getContext());

            LeafParticipant p = (LeafParticipant)pMap.get(participantName);

            wfdUrl = (String)p.getParams()
                .get(Definitions.WORKFLOW_DEFINITION_URL);
            shouldWaitForResult = waitForResult((String)p.getParams()
                .get(Definitions.WAIT_FOR_RESULT));
        }

        // from wfd

        if (wfdUrl == null)
        {
            wfdUrl = (String)getParams()
                .get(Definitions.WORKFLOW_DEFINITION_URL);
            shouldWaitForResult = waitForResult((String)getParams()
                .get(Definitions.WAIT_FOR_RESULT));
        }

        if (wfdUrl == null)
        {
            throw new DispatchingException
                ("Couldn't determine target flow. "+
                 "Declare it either in WI, PMAP or WFD.");
        }

        //
        // determine replyTo
        
        FlowExpressionId replyTo = null;

        if (shouldWaitForResult)
            //
            // launch subflow (its end will resume the current flow)
        {
            replyTo = iwi.getLastExpressionId();
        }

        //
        // prepare launchItem

        final LaunchItem li = new LaunchItem
            (wfdUrl,
             replyTo,
             iwi);

        //
        // prepare dispatcher
        // (if there is no 'finalDispatcher' or if it's for the same engine, 
        // dispatch locally)
        
        //String engineId = (String)getContext().get(Definitions.ENGINE_ID);
        final String engineId = getContext().getApplicationName();

        /*
        if (engineId == null)
        {
            throw new DispatchingException
                ("Parameter '"+Definitions.ENGINE_ID+
                 "' is missing in engine configuration, it should be set "+
                 "to the engine's participantName. Cannot launch any flow.");
        }
        */
        
        if (this.finalDispatcher == null ||
            engineId.equals(participantName))
        {
            String flowInstanceId = null;
            try
            {
                flowInstanceId = Definitions
                    .getLauncher(getContext())
                    .launch(li);
            }
            catch (OpenWfeException owe)
            {
                throw new DispatchingException
                    ("Failed to launch subflow", owe);
            }

            if ( ! shouldWaitForResult)
                continueCurrentFlowDirectly(iwi);

            return flowInstanceId;
        }

        //
        // dispatch ( <=> launch)
        
        // instantiate finalDispatcher
        
        try
        {
            this.finalDispatcher.init
                (getName()+".finalDispatcher",
                 getContext(),
                 getParams());
        }
        catch (Exception e)
        {
            throw new DispatchingException
                ("Failed to build and init finalDispatcher '"+
                 this.finalDispatcher.getClass().getName()+
                 "' for participant '"+getName()+"'", 
                 e);
        }

        // give launchItem to the finalDispatcher
        
        this.finalDispatcher.dispatch(li);

        continueCurrentFlowDirectly(iwi);

        return null;
    }

}