simpleexpressionpool.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: SimpleExpressionPool.java,v 1.44 2005/07/17 16:31:49 jmettraux Exp $
 */

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

package openwfe.org.engine.impl.expool;

import openwfe.org.MapUtils;
import openwfe.org.Application;
import openwfe.org.AbstractService;
import openwfe.org.ServiceException;
import openwfe.org.OpenWfeException;
import openwfe.org.ApplicationContext;
import openwfe.org.xml.XmlUtils;
import openwfe.org.time.Time;
import openwfe.org.engine.Definitions;
import openwfe.org.engine.control.auth.ControlPermission;
import openwfe.org.engine.expool.PoolException;
import openwfe.org.engine.expool.ExpressionPool;
import openwfe.org.engine.expool.ExpressionStore;
import openwfe.org.engine.history.History;
import openwfe.org.engine.workitem.WorkItem;
import openwfe.org.engine.workitem.InFlowWorkItem;
import openwfe.org.engine.dispatch.DispatchingException;
import openwfe.org.engine.expressions.GoneParentId;
import openwfe.org.engine.expressions.FlowExpression;
import openwfe.org.engine.expressions.ApplyException;
import openwfe.org.engine.expressions.ReplyException;
import openwfe.org.engine.expressions.FlowExpressionId;
import openwfe.org.engine.expressions.ExpressionWithTimer;
import openwfe.org.engine.expressions.ExpressionWithTimeOut;
import openwfe.org.engine.expressions.CompositeFlowExpression;
import openwfe.org.engine.expressions.raw.RawExpression;
import openwfe.org.engine.expressions.state.NormalState;
import openwfe.org.engine.expressions.state.FrozenState;
import openwfe.org.engine.expressions.state.ExpressionState;
import openwfe.org.engine.participants.Participant;
import openwfe.org.engine.participants.ParticipantMap;


/**
 * The pool of expressions : it stores workflow instances as expression bits.
 * In fact, it merely orchestrates this, the real storage work is done
 * by ExpressionStore implementations.
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Date: 2005/07/17 16:31:49 $
 * <br>$Id: SimpleExpressionPool.java,v 1.44 2005/07/17 16:31:49 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public class SimpleExpressionPool

    extends AbstractService

    implements ExpressionPool

{

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

    //
    // INNER CLASSES

    //
    // CONSTANTS

    //
    // FIELDS

    private ExpressionStore store = null;

    private java.util.TimerTask timerTask = null;
    private java.util.TimerTask purgeTask = null;

    //
    // CONSTRUCTORS

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

        //
        // determine purge frequency and start purge daemon

        String sPurgeFrequency = MapUtils.getAsString
            (getParams(), PURGE_FREQUENCY, DEFAULT_PURGE_FREQUENCY);

        long purgeFrequency = Time.parseTimeString(sPurgeFrequency);
        
        this.purgeTask = new java.util.TimerTask()
        {
            public void run ()
            {
                try
                {
                    purge();
                }
                catch (final Throwable t)
                {
                    log.warn("purgeTask : problem", t);
                }
            }
        };

        Application.getTimer().schedule
            (this.purgeTask,
             10 * 1000,  // start after 10s
             purgeFrequency);

        log.info("started purge daemon every '"+sPurgeFrequency+"'");

        //
        // determine whenCheck freq and start whenCheck daemon

        String sTimerFrequency = (String)serviceParams.get(TIMER_FREQUENCY);

        if (sTimerFrequency == null)
            sTimerFrequency = (String)serviceParams.get(WHEN_FREQUENCY);

        if (sTimerFrequency == null)
            sTimerFrequency = DEFAULT_TIMER_FREQUENCY;

        long timerFrequency = Time.parseTimeString(sTimerFrequency);

        this.timerTask = new java.util.TimerTask()
        {
             public void run ()
             {
                 try
                 {
                    checkExpressionsWithTimer();
                 }
                 catch (final Throwable t)
                 {
                     log.warn("timerTask : problem", t);
                 }
             }
        };

        Application.getTimer().schedule
            (this.timerTask,
             15 * 1000,  // start after 15s
             timerFrequency);

        log.info("started timer daemon every '"+sTimerFrequency+"'");

        //
        // display OpenWFE version in logs
        
        log.info("OpenWFE version : "+Definitions.OPENWFE_VERSION);
    }

    //
    // METHODS

    public void stop ()
        throws ServiceException
    {
        super.stop();

        this.timerTask.cancel();
        log.info("TimerDaemon stopped.");

        this.purgeTask.cancel();
        log.info("PurgeDaemon stopped.");

        log.info("Service '"+getName()+"' stopped.");
    }

    /**
     * Usually called by WorkflowInstanceBuilders to add a freshly created
     * expression to the pool.
     */
    public void add (final FlowExpression fe)
        throws PoolException
    {
        fe.setApplicationContext(getContext());

        //
        // then store it on the disk
        
        getStore().storeExpression(fe);
    }

    /**
     * Stores the flow expression (as it may have changed).
     */
    public void update (final FlowExpression fe)
        throws PoolException
    {
        getStore().storeExpression(fe);
    }

    /**
     * Retrieves an expression from the pool.
     * If the expression cannot be retrieved from the pool, null will be
     * returned.
     */
    public FlowExpression fetch (final FlowExpressionId fei)
    {
        //log.debug("fetch()");

        FlowExpression result = null;
        try
        {
            result = getStore().loadExpression(fei);

            //log.debug("fetch() expression got loaded");

            //result.setApplicationContext(getContext());
                // 
                // done by the store
        }
        catch (PoolException pe)
        {
            log.info("fetch() Failed to retrieve expression "+fei, pe);
            return null;
        }

        return result;
    }

    /**
     * Returns the Ur-Expression : an expression unique to the engine, its 
     * only task (as of 1.5.1) is to hold variables global to all workflow
     * instances.
     */
    public FlowExpression fetchUrExpression ()
    {
        final FlowExpression ur = getStore().loadUrExpression();

        ur.setApplicationContext(this.getContext());

        return ur;
    }

    /**
     * given an id, returns the root expression of the flow
     */
    public FlowExpression fetchRootOfFlow (final FlowExpressionId fei)
    {
        final FlowExpression fe = fetch(fei);
        final FlowExpressionId parentId = fe.getParent();
        if (parentId == null) return fe;
        return fetchRootOfFlow(parentId);
    }

    protected void log 
        (final FlowExpressionId fei, 
         final WorkItem wi,
         final String eventCode, 
         final String message)
    {
        final History history = Definitions.getHistory(getContext());

        log.debug(""+fei+" :: "+eventCode+" :: "+message);

        if (history == null) return;

        history.log(fei, wi, eventCode, null, message);
            // participantName is set to null
    }

    /**
     * Applies an expression. 
     * This method is usually called by expressions on their subexpressions or
     * by a launchListener on a rootExpression of a workflow just instantiated.
     */
    public void apply 
        (final FlowExpressionId fei, final InFlowWorkItem wi)
    throws 
        ApplyException
    {
        final FlowExpression fe = fetch(fei);

        if (fe == null)
        {
            log.warn
                ("Failed to find expression  "+fei+"  cannot apply it.");
            throw new ApplyException
                ("Failed to find expression  "+fei+"  cannot apply it.");
        }

        log(fei, wi, History.EVT_DEBUG, "applying");

        fe.tag(wi);
        fe.touchApplyTime();

        log.debug("apply() tagged wi to "+wi.getLastExpressionId());

        getState(fe).apply(wi);
    }

    /**
     * A shortcut to 
     * apply (workflowInstanceId, flowExpressionId, inFlowWorkItem)
     */
    public void apply
        (final FlowExpression fe, final InFlowWorkItem wi)
    throws 
        ApplyException
    {
        this.apply(fe.getId(), wi);
    }

    /**
     * Replies to the parent of the given flow expression, with the given 
     * workitem.
     */
    public void replyToParent
        (final FlowExpression fe, 
         final InFlowWorkItem wi)
    throws 
        ReplyException
    {
        if (fe.getNext() != null)
        {
            try
            {
                this.apply(fe.getNext(), wi);
            }
            catch (final ApplyException ae)
            {
                throw new ReplyException
                    ("Failed to apply next "+fe.getNext(), ae);
            }

            this.removeExpression(fe);
            return;
        }

        //
        // end of a flow

        if (fe.getParent() == null)
        {
            //log.debug("replyToParent() no parent, end of flow at "+fe.getId());

            String message = "";
            if (fe.getId().isInSubFlow()) message = "sub";

            log(fe.getId(), wi, History.EVT_FLOW_END, "");

            this.removeExpression(fe);