abstractworkitemstore.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: AbstractWorkItemStore.java,v 1.42 2005/07/07 08:57:14 jmettraux Exp $
 */

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

package openwfe.org.worklist.impl;

import javax.security.auth.Subject;

import openwfe.org.Cache;
import openwfe.org.MapUtils;
import openwfe.org.Application;
import openwfe.org.AbstractService;
import openwfe.org.ServiceException;
import openwfe.org.ApplicationContext;
import openwfe.org.auth.BasicPrincipal;
import openwfe.org.time.Time;
import openwfe.org.engine.workitem.CancelItem;
import openwfe.org.engine.workitem.InFlowWorkItem;
import openwfe.org.engine.workitem.WorkItemCoder;
import openwfe.org.engine.workitem.WorkItemCoderLoader;
import openwfe.org.engine.dispatch.DispatchingException;
import openwfe.org.engine.expressions.FlowExpressionId;
import openwfe.org.engine.participants.Participant;
import openwfe.org.engine.participants.ParticipantMap;
import openwfe.org.worklist.Header;
import openwfe.org.worklist.CachedHeaders;
import openwfe.org.worklist.HeaderFactory;
import openwfe.org.worklist.WorkListException;
import openwfe.org.worklist.store.Lock;
import openwfe.org.worklist.store.WorkItemStore;
import openwfe.org.worklist.store.StoreException;
import openwfe.org.worklist.auth.StorePermission;


/**
 * A lot of things that were developed as 'FileWorkItemStore' can be found
 * here, these functionalities will now be shared by other WorkItemStore
 * implementations, most notably the XdbcWorkItemStore.
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Date: 2005/07/07 08:57:14 $
 * <br>$Id: AbstractWorkItemStore.java,v 1.42 2005/07/07 08:57:14 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public abstract class AbstractWorkItemStore

    extends AbstractService

    implements WorkItemStore

{

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

    //
    // CONSTANTS (definitions)

    /**
     * The parameter 'cacheSize' defines how many workitems should be cached
     * in memory. The bigger the size the faster workitem retrieval may
     * be.
     */
    public final static String P_CACHE_SIZE 
        = "cacheSize";

    /**
     * Constant for the parameter named 'headerFactory' : a header is a 
     * summary of a workitem for display in a selection list, a header
     * factory is a piece of code that creates a header for a workitem. Use
     * this parameter to indicate the workitem store which header factory
     * (an OpenWFE like an other) it should use.
     */
    public final static String P_HEADER_FACTORY
        = "headerFactory";

    /**
     * Constant for the time parameter named 'lockTimeout' : how many
     * time an idle lock should be maintained on a workitem ?
     */
    public final static String P_LOCK_TIMEOUT
        = "lockTimeout";

    /**
     * Constant for the time parameter named 'unlockFrequency' : how 
     * frequently should the workitem store check for workitem whose
     * locks did time out ?
     */
    public final static String P_UNLOCK_FREQUENCY
        = "unlockFrequency";

    /**
     * Constant for the time parameter named 'maxStorageThreads' : after how
     * many concurrent storage thread should storage be performed sequentially
     * (lower response time) to avoid a JVM crash ?
     */
    public final static String P_MAX_STORAGE_THREADS
        = "maxStorageThreads";

    /**
     * The parameter 'workItemCoder' should point to the name of a workitem 
     * coder as defined by the 'workItemCoderLoader' service.
     */
    public final static String P_WORKITEM_CODER
        = "workItemCoder";

    /**
     * If the parameter 'default' for this store is set to 'true' or 'yes', 
     * the store will be a default store.
     */
    public final static String P_DEFAULT
        = "default";

    /** 
     * Set to 15m
     */
    public final static String DEFAULT_LOCK_TIMEOUT
        = "15m";

    /**
     * Set to 7m
     */
    public final static String DEFAULT_UNLOCK_FREQUENCY
        = "7m";

    /**
     * Set to 100 (workitems)
     */
    public final static int DEFAULT_CACHE_SIZE
        = 100;

    /**
     * Set to 100 (concurrent storage threads)
     */
    public final static int DEFAULT_MAX_STORAGE_THREADS
        = 100;

    //
    // FIELDS

    private Cache cache = null;

    private HeaderFactory headerFactoryService = null;

    private CachedHeaders cachedHeaders = null;
        // no headers determined for the moment

    private String[] acceptedParticipants = null;

    private java.util.Map lockMap = new java.util.HashMap();
    private long lockTimeout = 0;
    private UnlockDaemon unlockDaemon = null;

    private int maxStorageThreads = 30;
    private int activeStorageThreads = 0;

    private String workItemCoderName = null;

    //
    // CONSTRUCTORS

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

        //
        // init cache

        final int cacheSize = MapUtils.getAsInt
            (getParams(), P_CACHE_SIZE, DEFAULT_CACHE_SIZE);

        this.cache = new Cache(cacheSize);

        log.info("init() cache size set to "+this.cache.size());

        //
        // determine max storage threads
        
        this.maxStorageThreads = MapUtils.getAsInt
            (getParams(), 
             P_MAX_STORAGE_THREADS, 
             DEFAULT_MAX_STORAGE_THREADS);

        log.info("init() max storage threads set to "+this.maxStorageThreads);

        //
        // determine workItemCoder
        
        this.workItemCoderName = MapUtils.getAsString
            (getParams(),
             P_WORKITEM_CODER);

        log.info("init() workItemCoder set to '"+this.workItemCoderName+"'");

        //
        // init accepted participants
        
        initAcceptedParticipants(serviceParams);

        //
        // init UnlockDaemon
        
        initUnlockDaemon();

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

    //
    // GETTERS and SETTERS

    //
    // METHODS

    /**
     * Loads the workitem coder
     */
    public WorkItemCoder getCoder ()
    {
        final WorkItemCoderLoader coderLoader = openwfe.org.engine.Definitions
            .getWorkItemCoderLoader(getContext());

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

        return coderLoader.getDefaultCoder();
    }

    //
    // METHODS from WorkItemStore

    /**
     * Returns true if the given workitem is locked.
     */
    public boolean isLocked (final FlowExpressionId workitemId)
    {
        return this.lockMap.keySet().contains(workitemId);
    }

    /**
     * Returns the lock set on the workitem, will return null if no lock is set
     * on the workitem.
     */
    public Lock getLock (final FlowExpressionId workitemId)
    {
        return (Lock)this.lockMap.get(workitemId);
    }

    public boolean isDefaultStore ()
    {
        return MapUtils.getAsBoolean(getParams(), P_DEFAULT, false);
    }

    /**
     * Adds the given workitem to this expression store.
     */
    public void store (final InFlowWorkItem wi)
        throws StoreException
    {
        log.debug("store() in '"+getName()+"' for "+wi.getLastExpressionId());

        //
        // cache workitem

        this.cache.put(wi.getLastExpressionId(), wi);

        //logDebugCache();

        //
        // uncache headers

        this.cachedHeaders = null;

        //
        // 'physical' storage

        if (this.activeStorageThreads >= this.maxStorageThreads)
            //
            // unthreaded storage
        {
            storeWorkItem(wi);
        }
        else
            //
            // threaded storage
        {
            this.activeStorageThreads++;

            log.debug
                ("store() this.activeStorageThreads = "+
                 this.activeStorageThreads);

            (new Thread()
             {
                 public void run ()
                 {
                     final FlowExpressionId fei = wi.getLastExpressionId();
                     this.setName
                        ("storage thread for "+fei.getWorkflowInstanceId()+
                         " exp "+fei.getExpressionId());

                     try
                     {
                         AbstractWorkItemStore.this.storeWorkItem(wi);
                     }
                     catch (final Throwable t)
                     {
                         //log.warn
                         //    ("store() failed to store workitem "+
                         //     wi.getLastExpressionId()+
                         //     " : "+t);
                         log.error
                             ("store() failed to store workitem "+
                              wi.getLastExpressionId(), 
                              t);
                     }

                     AbstractWorkItemStore.this.activeStorageThreads--;
                 }
             }).start();
         }

    }

    public void cancel (final CancelItem ci)
        throws StoreException
    {
        final FlowExpressionId id = ci.getLastExpressionId();

        this.cache.remove(id);
        this.cachedHeaders = null;

        removeWorkItem(id);
    }

    /**
     * Updates a workitem in the store
     */
    public void save (final Subject s, final InFlowWorkItem wi)
        throws StoreException
    {
        java.security.AccessController.checkPermission
            (StorePermission.newStorePermission(getName(), "write"));

        synchronized (this) // check impact on perf
        {
            final FlowExpressionId id = wi.getLastExpressionId();

            //
            // is the item locked ?
            
            Lock lock = (Lock)this.lockMap.get(id);
            if (lock != null)
            {
                Subject locker = lock.getLocker();

                //
                // is the subject the locker ?
                
                if ( ! s.equals(locker))
                {
                    throw new StoreException
                        ("WorkItem '"+id+
                         "' is already locked by someone else.");
                }
            }
            else
            {
                //log.debug("Saving a workitem that was not locked before...");

                throw new StoreException
                    ("Cannot save workitem : you have no lock on it.");
            }

            //
            // proceed

            wi.touch();
                // update wi.lastModified

            store(wi);

            //
            // notify : the headers for this participant
            // are not up to date anymore

            this.cachedHeaders = null;

            // leave lock untouched
        }
    }