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;

     }

 }