xlobexpressionstore.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: XlobExpressionStore.java,v 1.3 2005/07/17 16:31:50 jmettraux Exp $
 */

//
// XlobExpressionStore.java
//
// [e-mail]
//
// generated with 
// jtmpl 1.1.00 16.08.2003 John Mettraux ([e-mail])
//

package openwfe.org.xlob.engine;

import openwfe.org.ServiceException;
import openwfe.org.ApplicationContext;
import openwfe.org.xml.XmlUtils;
import openwfe.org.engine.expool.PoolException;
import openwfe.org.engine.impl.expool.AbstractExpressionStore;
import openwfe.org.engine.expressions.ReplyException;
import openwfe.org.engine.expressions.FlowExpression;
import openwfe.org.engine.expressions.FlowExpressionId;
import openwfe.org.engine.expressions.ExpressionWithTimeOut;
import openwfe.org.xlob.XlobSession;
import openwfe.org.xlob.XlobException;


/**
 * Storing expressions through Xlob
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Id: XlobExpressionStore.java,v 1.3 2005/07/17 16:31:50 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public class XlobExpressionStore

    extends AbstractExpressionStore

{

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

    //
    // CONSTANTS & co

    /* *
     * This prefix is appended at the beginning of each xdbc clientId :
     * if the xdbc set of SQL tables is used by other applications / components
     * it will be easier to fetch expressions : their clientId should all
     * begin with 'owfe_exp'
     * /
    public final static String EXP_PREFIX = "owfe_exp";
     */

    //
    // FIELDS

    private XlobSession xlobSession = null;

    //
    // CONSTRUCTORS

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

        //
        // create xdbc session
        
        this.xlobSession = openwfe.org.xlob.XlobSessionImpl
            .createSession(getContext(), getParams());
    }

    //
    // METHODS from ExpressionStore

    /**
     * stores the expression
     */
    public void storeExpression (final FlowExpression fe)
        throws PoolException
    {
        long start = System.currentTimeMillis();

        final Object monitor = getMonitorMap().getMonitor(fe.getId());

        log.debug
            ("storeExpression() >in> monitor "+monitor+" for "+fe.getId());

        synchronized (monitor)
        {
            try
            {
                this.xlobSession.storeBean(fe.getId(), fe);
            }
            catch (final XlobException xe)
            {
                throw new PoolException("storage failure", xe);
            }
        }

        log.debug
            ("storeExpression() <out< monitor "+monitor+" for "+fe.getId());

        long duration = System.currentTimeMillis() - start;
        log.debug("storing the expression took "+duration+" ms");
    }

    /**
     * removes an expression from the store
     */
    public void unstoreExpression (final FlowExpression fe)
        throws PoolException
    {
        final Object monitor = getMonitorMap().getMonitor(fe.getId());

        log.debug
            ("unstoreExpression() >in> monitor "+monitor+" for "+fe.getId());

        synchronized (monitor)
        {
            try
            {
                this.xlobSession.remove(fe.getId());
            }
            catch (final XlobException xe)
            {
                throw new PoolException
                    ("Failed to remove expression from xlob store", xe);
            }
        }

        log.debug
            ("unstoreExpression() <out< monitor "+monitor+" for "+fe.getId());
    }

    /**
     * loads expression from the store
     */
    public FlowExpression loadExpression (final FlowExpressionId fei)
        throws PoolException
    {
        try
        {
            final FlowExpression fe = 
                (FlowExpression)this.xlobSession.findBean(fei);

            fe.setApplicationContext(getContext());

            return fe;
        }
        catch (final XlobException xe)
        {
            throw new PoolException
                ("load failure", xe);
        }
    }

    /**
     * returns true if the expression behind the expression id is still
     * alive (present in the store).
     */
    public boolean isExpressionActive (final FlowExpressionId fei)
    {
        try
        {
            return (this.xlobSession.count(fei) > 0);
        }
        catch (final XlobException xe)
        {
            log.warn("isExpressionActive() failure", xe);
        }

        return false;
    }

    //
    // METHODS

    /**
     * Iterates over all the expression stored and returns the one of the
     * given 'assignClass'.
     * If null is passwed as assignClass, it will return all the expressions.
     */
    public java.util.Iterator contentIterator
        (final Class assignClass)
    {
        java.util.Set result = new java.util.HashSet();

        try
        {
            final String[] expressionShortNames =
                determineExpressionShortNames(assignClass);

            if (expressionShortNames == null)
                log.debug("contentIterator() esn : null");
            else
                log.debug("contentIterator() esn.length : "+expressionShortNames.length);

            if (expressionShortNames != null &&
                expressionShortNames.length > 0)
            {
                for (int i=0; i<expressionShortNames.length; i++)
                {
                    final FlowExpressionId criterion = new FlowExpressionId();
                    criterion.setExpressionName(expressionShortNames[i]);

                    fetchExpressions(criterion, result);
                }
            }
            else
            {
                fetchExpressions(null, result);
            }
        }
        catch (final Throwable t)
        {
            log.warn("contentIterator() failure", t);
            return null;
        }

        return result.iterator();
    }

    /*
     * Used by contentIterator().
     */
    private void fetchExpressions 
        (final FlowExpressionId criterion, final java.util.Set result)
    throws
        XlobException
    {
        final java.util.Set expressions = 
            this.xlobSession.queryBeans(criterion);

        final java.util.Iterator it = expressions.iterator();
        while (it.hasNext())
        {
            final FlowExpression fe = (FlowExpression)it.next();

            fe.setApplicationContext(getContext());

            result.add(fe);
        }
    }

    /**
     * Returns how many expressions are stored in this ExpressionStore 
     * implementation.
     */
    public int size ()
    {
        try
        {
            return this.xlobSession.count(null);
        }
        catch (final XlobException xe)
        {
            log.warn("size() count failure", xe);
        }

        return -1;
    }

    //
    // METHODS from Service

    /**
     * Status is outputted as a JDOM element. The status is various
     * information about a service activities and state.
     */
    public org.jdom.Element getStatus ()
    {
        org.jdom.Element result = new org.jdom.Element(getName());

        result.addContent(XmlUtils.getClassElt(this));
        result.addContent(XmlUtils.getRevisionElt("$Id: XlobExpressionStore.java,v 1.3 2005/07/17 16:31:50 jmettraux Exp $"));

        org.jdom.Element eTotalExpressionCount = 
            new org.jdom.Element("expressionsStored");
        eTotalExpressionCount.addContent
            (new org.jdom.Text(""+this.size()));
        result.addContent(eTotalExpressionCount);

        /*
        //
        // count expressions per flow instance
        
        java.util.List l = null;
        try
        {
            l = this.xdbcSession.listClientIds(EXP_PREFIX+" %");
        }
        catch (XdbcException xe)
        {
            log.warn
                ("Failed to count expressions per flow instance "+
                 "for getStatus()", xe);
            return result;
        }

        java.util.Map expressionsPerFlow = new java.util.HashMap();
        java.util.Map expressionsPerInstance = new java.util.HashMap();

        java.util.Iterator it = l.iterator();
        while (it.hasNext())
        {
            String clientId = (String)it.next();

            clientId = clientId.substring(EXP_PREFIX.length()+1);
            int i = clientId.lastIndexOf(" ");
            clientId = clientId.substring(0, i);
            i = clientId.lastIndexOf(" ");
            clientId = clientId.substring(0, i);

            //log.debug("taking into account >"+clientId+"<");

            openwfe.org.Utils.inc(expressionsPerInstance, clientId);

            i = clientId.lastIndexOf(" ");
            clientId = clientId.substring(0, i);

            openwfe.org.Utils.inc(expressionsPerFlow, clientId);
        }

        org.jdom.Element eFlows = new org.jdom.Element("flows");

        it = expressionsPerFlow.keySet().iterator();
        while (it.hasNext())
        {
            String flowDef = (String)it.next();
            Integer count = (Integer)expressionsPerFlow.get(flowDef);

            org.jdom.Element eFlow = new org.jdom.Element("flow");
            eFlow.setAttribute("def", flowDef);
            eFlow.setAttribute("expressions", count.toString());

            eFlows.addContent(eFlow);
        }

        it = expressionsPerInstance.keySet().iterator();
        while (it.hasNext())
        {
            String flowId = (String)it.next();
            Integer count = (Integer)expressionsPerInstance.get(flowId);

            org.jdom.Element eFlow = new org.jdom.Element("flow");
            eFlow.setAttribute("id", flowId);
            eFlow.setAttribute("expressions", count.toString());

            eFlows.addContent(eFlow);
        }

        result.addContent(eFlows);
        */

        //
        // the end

        return result;
    }

}