abstractflowexpression.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: AbstractFlowExpression.java,v 1.29 2005/07/13 20:53:40 jmettraux Exp $
 */

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

package openwfe.org.engine.expressions;

import openwfe.org.Utils;
import openwfe.org.ReflectionUtils;
import openwfe.org.ApplicationContext;
import openwfe.org.time.Time;
import openwfe.org.misc.Text;
import openwfe.org.engine.Definitions;
import openwfe.org.engine.launch.Launcher;
import openwfe.org.engine.expool.PoolException;
import openwfe.org.engine.expool.ExpressionPool;
import openwfe.org.engine.history.History;
import openwfe.org.engine.workitem.WorkItem;
import openwfe.org.engine.workitem.InFlowWorkItem;
import openwfe.org.engine.expressions.raw.RawExpression;
import openwfe.org.engine.expressions.map.ExpressionMap;
import openwfe.org.engine.expressions.state.ExpressionState;
import openwfe.org.engine.participants.ParticipantMap;


/**
 * For each XML tag in an OpenWFE process definition, there is a FlowExpression
 * instance.
 * Each expression is tagged with (designated by) a flowExpressionId. You may
 * think of expression as pieces of workflow instance pointing to each other
 * through references (FlowExpressionId instances).
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Date: 2005/07/13 20:53:40 $
 * <br>$Id: AbstractFlowExpression.java,v 1.29 2005/07/13 20:53:40 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public abstract class AbstractFlowExpression

    implements FlowExpression

{

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

    //
    // FIELDS

    /* *
     * The flowExpressionId of this flowExpression
     */
    private FlowExpressionId id = null;

    /* *
     * The flowExpressionId of the parent of this expression, if it's set 
     * to null, then the expression has no parent, is a root.
     */
    private FlowExpressionId parent = null;

    private FlowExpressionId next = null;
    private FlowExpressionId previous = null;

    /* *
     * The apply time when set means that the flow expression got 'applied'
     * and will contain a datetime string for this apply time.
     */
    private String applyTime = null;

    /* *
     * The engine, when manipulating a flowExpression for 'running' a flow
     * instance gives it a reference to the applicationContext, the expression
     * may then use this reference to talk back to the engine and for example
     * ask for the participantMap for dispatching purposes.
     */
    private transient ApplicationContext applicationContext = null;

    /* *
     * This map contains the attributes (key, value as string) of the
     * XML tag corresponding to this flowExpression.
     * For instance, if the tag in the flow definition was :<br>
     * <pre>&lt;participant ref="toto" timeout="2h"/&gt;</pre><br>
     * the attributes map will contain { 'ref': 'toto', 'timeout': '2h' }.
     */
    private java.util.Map attributes = null;

    /* *
     * Where 'variables' are linked in the scope defined by the flowExpression.
     * Such a scope is more useful for a composite expression than for an
     * expression with no children.
     */
    private java.util.Map variables = null;

    private ExpressionState state = null;

    //
    // CONSTRUCTORS

    /**
     * The constructor for a flow expression. The bulk work of initialization
     * is though done in the 'build()' method.
     */
    public AbstractFlowExpression ()
    {
        super();

        this.attributes = new java.util.HashMap(7);
        this.variables = new java.util.HashMap(7);
    }

    //
    // BEAN METHODS

    /**
     * Returns the FlowExpressionId of this expression.
     */
    public FlowExpressionId getId () { return this.id; }

    /**
     * Returns the FlowExpressionId of the parent expression of this
     * expression.
     */
    public FlowExpressionId getParent () { return this.parent; }

    /**
     * Sometimes (especially in the case of a sequence), having children
     * expressions always replying to the parent is not necessary, they
     * can directly apply their neighbor, this 'next' member is here to
     * allow such behaviour.
     */
    public FlowExpressionId getNext () { return this.next; }

    /**
     * A parallel to the 'next' field : this 'previous' points to the
     * previous expression in the flat sequence, this is used mainly
     * in cancel() where a parent knows only about the last expression
     * in a sequence and thus calls cancel on it, this last expression then
     * calls cancel() on its previous expression (if they are still around).
     */
    public FlowExpressionId getPrevious () { return this.previous; }

    /**
     * Returns the string representing the moment at which this expression
     * got applied (or null if it was not yet applied).
     */
    public String getApplyTime () { return this.applyTime; }

    /**
     * Returns the attribute of this expression (they tune the behaviour
     * of the expression).
     */
    public java.util.Map getAttributes () { return this.attributes; }

    /**
     * Returns the variables bound at this expression's level.
     */
    public java.util.Map getVariables () { return this.variables; }

    public void setId (FlowExpressionId fei) { this.id = fei; }
    public void setParent (FlowExpressionId fei) { this.parent = fei; }
    public void setNext (FlowExpressionId fei) { this.next = fei; }
    public void setPrevious (FlowExpressionId fei) { this.previous = fei; }
    public void setApplyTime (String isoDate) { this.applyTime = isoDate; }
    public void setAttributes (java.util.Map m) { this.attributes = m; }
    public void setVariables (java.util.Map m) { this.variables = m; }

    public void setApplicationContext (ApplicationContext ac) { this.applicationContext = ac; }

    //
    // METHODS

    /**
     * This method returns the applicationContext currently attached to this 
     * FlowExpression.
     */
    public ApplicationContext context ()
    {
        return this.applicationContext;
    }

    /**
     * This method will return false if the given String contains some
     * $ notation element, it's generally used from inside lookupAttribute().
     * For instance <pre>referencesNoVariable("field-${name}")</pre> will yield
     * false.
     */
    protected static boolean referencesNoVariable (final String attributeValue)
    {
        return (attributeValue == null || attributeValue.indexOf("${") < 0);
    }

    /**
     * Looks a process definition attribute ie in the example<br>
     * &lt;participant ref="toto" /&gt;<br>
     * lookupAttribute("ref");<br>
     * will return "toto".
     * If it were<br>
     * &lt;participant ref="toto_${index}" /&gt;<br>
     * and the variable "index" would be set to "2",<br>
     * lookupAttribute("ref");<br>
     * would have returned "toto_2".
     */
    public String lookupAttribute 
        (final String attributeName,
         final InFlowWorkItem wi)
    {
        log.debug("lookupAttribute() '"+attributeName+"'");

        final String attributeValue = 
            (String)this.attributes.get(attributeName);

        log.debug("lookupAttribute() value is '"+attributeValue+"'");

        if (referencesNoVariable(attributeValue)) return attributeValue;

        log.debug("lookupAttribute() doing substitution...");

        final VariableMap vMap = new VariableMap(this, wi);

        return Text.substitute(attributeValue, vMap);
    }

    /**
     * sets the apply time to now
     */
    public void touchApplyTime ()
    {
        this.setApplyTime(Time.toIsoDate());
    }

    /**
     * Looks up a variable set in this expression, will return null if
     * no such variable is set here.
     */
    public Object lookupLocalVariable (final String variableName)
    {
        return this.variables.get(variableName);
    }

    /**
     * Looks for a boolean result variable in the current scope.
     * Used by the 'if' and the 'when' expression.
     */
    public boolean lookupLocalBooleanResult ()
        throws ReplyException
    {
        Object o = lookupLocalVariable(ValueUtils.BOOLEAN_RESULT);

        if (o == null)
        {
            throw new ReplyException
                 ("lookupLocalBooleanVariable() no boolean result found");
        }

        //log.debug("o.class is "+o.getClass().getName());

        if ( ! (o instanceof Boolean))
        {
            throw new ReplyException
                ("lookupLocalBooleanVariable() boolean type expected, "+
                 "found "+o.getClass());
        }

        return ((Boolean)o).booleanValue();
    }

    /**
     * removes any boolean result variable in this expression
     * (used by CondExpression)
     */
    public void cleanBooleanResult ()
    {
        this.setLocalVariable(ValueUtils.BOOLEAN_RESULT, null);
    }

    /**
     * Sets a variable locally.
     * This method should not be called directly by an expression but by
     * the expression pool.<br>
     * When an expression wants to set a variable, it should do
     * so by calling ExpressionPool.setVariableInParent()
     */
    public void setLocalVariable (final String variableName, final Object value)
    {
        log.debug
            ("setLocalVariable() setting '"+variableName+"' in "+this.getId());

        this.variables.put(variableName, value);

        this.storeItself();
    }

    /**
     * Takes care of looking up a variable (locally or from the expression 
     * pool).
     */
    public Object lookupVariable (final String variableName)