2009/05/20 - Apache Shale has been retired.

   /*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to you under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.shale.dialog.scxml;
  
  import java.io.Serializable;
  import java.util.HashMap;
  import java.util.Map;
  
  import javax.faces.context.FacesContext;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.commons.scxml.model.SCXML;
  import org.apache.shale.dialog.Constants;
  import org.apache.shale.dialog.DialogContext;
  import org.apache.shale.dialog.DialogContextManager;
  import org.apache.shale.dialog.base.AbstractDialogContextManager;
  import org.apache.shale.dialog.scxml.config.DialogMetadata;
  
  /***
   * <p>Implementation of {@link DialogContextManager} for integrating
   * Commons SCXML into the Shale Dialog Manager.</p>
   *
   * @since 1.0.4
   */
  public final class SCXMLDialogManager extends AbstractDialogContextManager
    implements Serializable {
  
  
      // ------------------------------------------------------ SCXMLDialogManager Variables
  
  
      /***
       * Serial version UID.
       */
      private static final long serialVersionUID = -4358734655564376781L;
  
  
      /***
       * <p><code>Map</code> of {@link SCXML} configurations, keyed
       * by dialog name.  This value is lazily instantiated.</p>
       */
      private Map dialogs = null;
  
  
      /***
       * <p>Map containing all currently active {@link DialogContext} instances for
       * the current user.</p>
       */
      private final Map map = new HashMap();
  
  
      /***
       * <p>The <code>Log</code> instance for this class.  This value is lazily
       * instantiated, and is also transient and may need to be regenerated.</p>
       */
      private transient Log log = null;
  
  
      /***
       * <p>Serial number used to generate dialog instance identifiers.</p>
       */
      private int serial = 0;
  
  
      // -------------------------------------------------------- DialogContextManager Methods
  
  
      /*** {@inheritDoc} */
      public DialogContext create(FacesContext context, String name) {
  
          return create(context, name, null);
  
      }
  
  
      /*** {@inheritDoc} */
      public DialogContext create(FacesContext context, String name, DialogContext parent) {
  
          // Obtain the dialog metadata for the specified dialog
          DialogMetadata dialog = (DialogMetadata) dialogs(context).get(name);
          if (dialog == null) {
              throw new IllegalArgumentException("No definition for dialog name '"
                                                 + name + "' can be found");
         }
 
         // Validate the specified parent (if any)
         String parentDialogId = null;
         if (parent != null) {
             parentDialogId = parent.getId();
             if (parent != get(parentDialogId)) {
                 throw new IllegalStateException("The specified parent DialogContext '"
                         + parentDialogId + "' is not managed by this DialogContextManager");
             }
         }
 
         // Configure a new SCXMLDialogContext instance
         SCXMLDialogContext instance = new SCXMLDialogContext(this, dialog, generateId(),
                 parentDialogId);
         instance.setData(new HashMap());
         synchronized (map) {
             map.put(instance.getId(), instance);
         }
         context.getExternalContext().getRequestMap().put(Constants.CONTEXT_BEAN, instance);
         fireOnCreate(instance);
 
         if (log().isDebugEnabled()) {
             log().debug("create(Created DialogContext instance with ID '"
                 + instance.getId() + "' for dialog with name '" + name + "'");
         }
 
         return instance;
     }
 
 
     /*** {@inheritDoc} */
     public DialogContext get(String id) {
         return (DialogContext) map.get(id);
     }
 
 
     /*** {@inheritDoc} */
     public void remove(DialogContext instance) {
         boolean found = false;
         // Cache ID in case any of the listeners destroy instance onRemove()
         String id = instance.getId();
         synchronized (map) {
             found = map.remove(id) == instance;
         }
         if (found) {
             ((SCXMLDialogContext) instance).deactivate();
             fireOnRemove(instance);
 
             if (log().isDebugEnabled()) {
                 log().debug("remove(Removed DialogContext instance with ID '"
                     + id + "'");
             }
 
         }
     }
 
 
     // --------------------------------------------------------- Private Methods
 
 
     /***
      * <p>Return a <code>Map</code> of the configured {@link SCXML} instances,
      * keyed by logical dialog name.</p>
      *
      * @param context FacesContext for the current request
      * @return Map of {@link SCXML} instances, keyed by logical dialog name
      */
     private Map dialogs(FacesContext context) {
 
         // Return the cached instance (if any)
         if (this.dialogs != null) {
             return this.dialogs;
         }
 
         // Return the previously configured application scope instance (if any)
         this.dialogs = (Map)
           context.getExternalContext().getApplicationMap().get(Globals.DIALOGS);
         return this.dialogs;
 
     }
 
 
     /***
      * <p>Generate and return a new dialog identifier.  FIXME - switch to
      * something that creates randomized identifiers?</p>
      *
      * @return The generated identifier
      */
     private String generateId() {
         return "" + ++serial;
     }
 
 
     /***
      * <p>Return the <code>Log</code> instance for this instance.</p>
      *
      * @return The log instance
      */
     private Log log() {
         if (this.log == null) {
             this.log = LogFactory.getLog(SCXMLDialogManager.class);
         }
         return this.log;
     }
 
 }