/*
* $Header: /home/cvs/jakarta-struts/contrib/workflow/RegistryServlet.java,v 1.2 2002/12/08 07:28:11 rleland Exp $
* $Revision: 1.2 $
* $Date: 2002/12/08 07:28:11 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
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* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
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* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
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* information on the Apache Software Foundation, please see
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*/
package org.apache.struts.action;
import java.io.InputStream;
import javax.servlet.ServletException;
import javax.servlet.UnavailableException;
import javax.servlet.http.HttpServlet;
import org.apache.commons.digester.Digester;
import org.apache.commons.workflow.Activity;
import org.apache.commons.workflow.Context;
import org.apache.commons.workflow.ContextEvent;
import org.apache.commons.workflow.ContextListener;
import org.apache.commons.workflow.Step;
import org.apache.commons.workflow.StepException;
import org.apache.commons.workflow.base.BaseRuleSet;
import org.apache.commons.workflow.core.CoreRuleSet;
import org.apache.commons.workflow.io.IoRuleSet;
import org.apache.commons.workflow.web.WebContext;
import org.apache.commons.workflow.web.WebRuleSet;
import simple.workflow.Registry;
import simple.workflow.base.BaseRegistry;
/**
* <p>Demonstration servlet that illustrates one way that workflow support can
* be integrated into Struts. This servlet is used to instantiate the Registry
* of Activities and expose them to the application. Processing of the Activities
* is expected to take place in an <code>Activity</code> Action.</p>
*
* <p>Note: The functionality of this Servlet could be replaced by the new
* ServiceManager.</p>
*
* <p>Initialization parameters (defaults in square brackets):</p>
* <ul>
* <li><strong>registry</strong> - Context-relative resource path to the
* definition file for the Activities to be initialized by this servlet.</li>
* <li><strong>registry-key</strong> - Name of the session attribute under
* which the <code>Registry</code> implementation is stored.
* [org.apache.commons.workflow.REGISTRY]</li>
* <li><strong>context-key</strong> - Name of the session attribute under
* which our current <code>Context</code> implementation is stored.
* [org.apache.commons.workflow.web.CONTEXT]</li>
* <li><strong>debug</strong> - The debugging detail level for this
* servlet, which controls how much information is logged. [0]</li>
* <li><strong>detail</strong> - The debugging detail level for the Digester
* we utilize in <code>initMapping()</code>, which logs to System.out
* instead of the servlet log. [0]</li>
* </ul>
*
* @author Craig R. McClanahan
* @author Ted Husted
* @version $Revision: 1.2 $ $Date: 2002/12/08 07:28:11 $
*/
public class RegistryServlet extends HttpServlet {
// ----------------------------------------------------- Instance Variables
/**
* The Activity for this servlet
* //:TODO: TEMPORARY
*/
protected Activity activity = null;
/**
* Default Name of the session attribute under which
* the current <code>Activity</code> is stored.
*/
public static String ACTIVITY =
"org.apache.commons.workflow.ACTIVITY";
/**
* Name of the session attribute under
* which the <code>Activity</code> is stored.
*/
protected String activityKey = ACTIVITY;
/**
* Default Name of the session attribute under which
* a current <code>Context</code> is stored.
*/
public static String CONTEXT =
"org.apache.commons.workflow.CONTEXT";
/**
* Name of the session attribute under
* which a current <code>Context</code> is stored.
*/
protected String contextKey = CONTEXT;
/**
* The Registry for this servlet
*/
protected Registry registry = null;
/**
* Default Name of the application attribute under which
* the <code>Registry</code> is stored.
*/
public static String REGISTRY =
"org.apache.commons.workflow.REGISTRY";
/**
* Name of the session attribute under
* which the <code>Registry</code> is stored.
*/
protected String registryKey = REGISTRY;
/**
* Default name for Registry XML document
*/
protected String registryPath = "WEB-INF/workflow.xml";
/**
* The debugging detail level for this servlet.
*/
private int debug = 0;
// --------------------------------------------------------- Public Properties
/**
* Set the <code>Activity</code> associated with this instance.
*
* @param activity The new associated Activity
*/
public void setActivity(Activity activity) {
this.activity = activity;
getServletContext().setAttribute(ACTIVITY,this.activity);
}
/**
* Return the name of the session attribute under which a current
* <code>Context</code> is stored.
*/
public String getContextKey() {
return contextKey;
}
/**
* Set the name of the session attribute under which a current
* <code>Context</code> is stored.
*/
protected void setContextKey(String contextKey) {
this.contextKey = contextKey;
}
/**
* Return Name of the application attribute under which this
* servlet is exposed.
*/
public String getRegistryKey() {
return registryKey;
}
/**
* Set the name of the session attribute under which a current
* <code>Registry</code> is stored.
*/
protected void setRegistryKey(String registryKey) {
this.registryKey = registryKey;
}
/**
* Return the Registry for this servlet
*/
protected Registry getRegistry() {
return (this.registry);
}
/**
* Set the <code>Registry</code> associated with this instance.
* Called by Digester via parse.
*
* @param regisry The new associated Registry
*/
public void setRegistry(Registry registry) {
this.registry = registry;
initRegistry();
getServletContext().setAttribute(
getRegistryKey(),getRegistry());
}
// --------------------------------------------------------- Public Methods
/**
* Perform any optimizations or related tasks on Registry once it is
* populated.
*/
protected void initRegistry() {
synchronized (this.registry) {
registry.initActivities();
}
}
/**
* Gracefully shut down any activity instances we have created.
*/
protected void destroyRegistry() {
synchronized (this.registry) {
registry.clearActivities();
}
}
/**
* Perform a graceful shutdown of this servlet instance.
*/
public void destroy() {
destroyRegistry();
}
/**
* Perform a graceful startup of this servlet instance.
*
* @exception ServletException if we cannot process the activity
* definition file for this activity
*/
public void init() throws ServletException {
// Record the debugging detail level settings
String debug = getServletConfig().getInitParameter("debug");
if (debug != null) {
try {
this.debug = Integer.parseInt(debug);
} catch (NumberFormatException e) {
throw new UnavailableException
("Debug initialization parameter must be an integer");
}
}
// Record the attribute name for our current Context
String contextKey = getServletConfig().getInitParameter("context-key");
if (contextKey != null)
setContextKey(contextKey);
// Record the attribute name for our current Context
String registryKey = getServletConfig().getInitParameter("registry-key");
if (registryKey != null)
setRegistryKey(registryKey);
// Parse the activity definition file for our Activity
String registryPath = getServletConfig().getInitParameter("registry");
if (registryPath != null)
this.registryPath = registryPath;
parse(this.registryPath);
// Check result of parse
if (activity == null)
throw new UnavailableException("No registry defined in resource "
+ registryPath);
}
// -------------------------------------------------------- Private Methods
/**
* Parse the specified activity definition file for this instance.
*
* @param path Context-relative resource path of the activity
* definition file
*
* @exception ServletException on any processing error in parsing
*/
private void parse(String path) throws ServletException {
// Get an input source for the specified path
InputStream is =
getServletContext().getResourceAsStream(path);
if (is == null)
throw new UnavailableException("Cannot access resource " +
path);
// Configure a Digester instance to parse our definition file
Digester digester = new Digester();
digester.setNamespaceAware(true);
digester.setValidating(false);
digester.push(this);
// Add rules to recognize the built-in steps that we know about
BaseRuleSet brs = new BaseRuleSet();
digester.addRuleSet(brs);
digester.addRuleSet(new CoreRuleSet());
digester.addRuleSet(new IoRuleSet());
digester.addRuleSet(new WebRuleSet());
// Add a rule to register the Activity being created
digester.setRuleNamespaceURI(brs.getNamespaceURI());
digester.addSetNext("activity", "setActivity",
"org.apache.commons.workflow.Activity");
// Parse the activity definition file
try {
digester.parse(is);
} catch (Throwable t) {
log("Cannot parse resource " + path, t);
throw new UnavailableException("Cannot parse resource " + path);
} finally {
try {
is.close();
} catch (Throwable u) {
;
}
}
}
}