/*

  * Copyright 1999-2001,2004 The Apache Software Foundation.

  * 

  * Licensed 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.commons.workflow.web;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.Enumeration;

 import java.util.HashSet;

 import java.util.Iterator;

 import java.util.Map;

 import java.util.Set;

 import javax.servlet.http.HttpSession;

 import org.apache.commons.workflow.base.BaseScope;

 import org.apache.commons.workflow.util.MapEntry;

 /**

  * <strong>HttpSessionScope</strong> is a specialized <code>Scope</code>

  * implementation corresponding the the attributes of a specified

  * <code>HttpSession</code>.

  *

  * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $

  * @author Craig R. McClanahan

  */

 public class HttpSessionScope extends BaseScope {

     // ----------------------------------------------------------- Constructors

     /**

      * Construct a new HttpSessionScope with no attached HttpSession.

      */

     public HttpSessionScope() {

         super();

     }

     /**

      * Construct a HttpSessionScope associated with the specified

      * HttpSession.

      *

      * @param httpSession The associated HttpSession

      */

     public HttpSessionScope(HttpSession httpSession) {

         super();

         setHttpSession(httpSession);

     }

     // ------------------------------------------------------------- Properties

     /**

      * The HTTP session with which we are associated.

      */

     protected HttpSession httpSession = null;

     public HttpSession getHttpSession() {

         return (this.httpSession);

     }

     public void setHttpSession(HttpSession httpSession) {

         this.httpSession = httpSession;

     }

     // ------------------------------------------------------------ Map Methods

     /**

      * Remove all beans from this Map and call <code>scopeCleared() on

      * all registered <code>ScopeListeners</code>.

      */

     public void clear() {

         // Accumulate a list of the elements to be cleared

         Enumeration names = httpSession.getAttributeNames();

         ArrayList list = new ArrayList();

         while (names.hasMoreElements()) {

             list.add((String) names.nextElement());

         }

         // Erase the accumulated elements

         int n = list.size();

         for (int i = 0; i < n; i++) {

             httpSession.removeAttribute((String) list.get(i));

         }

         support.fireScopeCleared();

     }

     /**

      * Return <code>true</code> if this map contains the specified key.

      *

      * @param key Key to be looked up

      */

     public boolean containsKey(Object key) {

         return (httpSession.getAttribute((String) key) != null);

     }

     /**

      * Return <code>true</code> if this map contains the specified value.

      *

      * @param value Value to be looked up

      */

     public boolean containsValue(Object value) {

         // Check all existing attributes for a match

         Enumeration names = httpSession.getAttributeNames();

         while (names.hasMoreElements()) {

             String name = (String) names.nextElement();

             if (value.equals(httpSession.getAttribute(name)))

                 return (true);

         }

         return (false);

     }

     /**

      * Return a set view of the mappings contained in this map.

      */

     public Set entrySet() {

         HashSet results = new HashSet();

         Enumeration names = httpSession.getAttributeNames();

         while (names.hasMoreElements()) {

             String name = (String) names.nextElement();

             results.add(new MapEntry(name, httpSession.getAttribute(name)));

         }

         return (results);

     }

     /**

      * Compare the specified object with this map for equality.

      *

      * @param object Object to be compared

      */

     public boolean equals(Object object) {

         return (httpSession.equals(object));

     }

     /**

      * Return the value to which this map maps the specified key.

      *

      * @param key Key to be looked up

      */

     public Object get(Object key) {

         return (get((String) key));

     }

     /**

      * Return the value to which this map maps the specified key.

      *

      * @param key Key to be looked up

      */

     public Object get(String key) {

         return (httpSession.getAttribute(key));

     }

     /**

      * Return the hash code value for this map.

      */

     public int hashCode() {

         return (httpSession.hashCode());

     }

     /**

      * Return <code>true</code> if this map is empty.

      */

     public boolean isEmpty() {

         // Check all existing attributes

         Enumeration names = httpSession.getAttributeNames();

         while (names.hasMoreElements())

             return (true);

         return (false);

     }

     /**

      * Return a set view of the keys contained in this map.

      */

     public Set keySet() {

         HashSet results = new HashSet();

         Enumeration names = httpSession.getAttributeNames();

         while (names.hasMoreElements())

             results.add(names.nextElement());

         return (results);

     }

     /**

      * Add or replace the bean associated with the specified key.

      *

      * @param key Key with which the new value should be associated

      *  (cannot be null)

      * @param bean Bean to be associated with this key (cannot be null)

      */

     public Object put(Object key, Object bean) {

         return (put((String) key, bean));

     }

     /**

      * Add the specified bean, associated with the specified key, to this

      * scope and replace any previous bean associated with this key.  If

      * the bean was added, call <code>beanAdded()</code> on all registered

      * listeners after the add is done.  If an old bean was replaced,

      * call <code>beanReplaced()</code> (passing the old value in the event)

      * on all registered <code>ScopeListeners</code> after the removal

      * is done.  If a bean was replaced, the old value is also returned;

      * otherwise <code>null</code> is returned.

      *

      * @param key Key with which the new value should be associated

      *  (cannot be null)

      * @param bean Bean to be associated with this key (cannot be null)

      *

      * @exception IllegalArgumentException if <code>key</code> or

      *  <code>bean</code> is null

      */

     public Object put(String key, Object bean) {

         if (key == null)

             throw new IllegalArgumentException("Key cannot be null");

         if (bean == null)

             throw new IllegalArgumentException("Value cannot be null");

         Object old = httpSession.getAttribute(key);

         if (old != null) {

             httpSession.setAttribute(key, bean);

             support.fireBeanReplaced(key, old);

         } else {

             httpSession.setAttribute(key, bean);

             support.fireBeanAdded(key, bean);

         }

         return (old);

     }

     /**

      * Copy all of the mappings from the specified map into this map,

      * firing appropriate <code>beanAdded()</code> and

      * <code>beanReplaced()</code> events along the way.

      *

      * @param in Map whose contents are to be added

      */

     public void putAll(Map in) {

         Iterator keys = in.keySet().iterator();

         while (keys.hasNext()) {

             Object key = keys.next();

             put(key, in.get(key));

         }

     }

     /**

      * Remove the bean associated with the specified key (if any), and return

      * the old value if removed.

      *

      * @param key Key of the bean to remove (cannot be null)

      */

     public Object remove(Object key) {

         return (remove((String) key));

     }

     /**

      * Remove the bean associated with the specified key (if any).  If such

      * a bean is found and removed, call <code>beanRemoved()</code> on all

      * registered <code>ScopeListeners</code> after the removal is done.

      * Return the old value (if any); otherwise return <code>null</code>.

      *

      * @param key Key of the bean to remove (cannot be null)

      *

      * @exception IllegalArgumentException if <code>key</code> is null

      */

     public Object remove(String key) {

         Object old = httpSession.getAttribute(key);

         if (old != null) {

             support.fireBeanRemoved(key, old);

             return (old);

         }

         return (null);

     }

     /**

      * Return the number of key-value mappings in this map.

      */

     public int size() {

         Enumeration names = httpSession.getAttributeNames();

         int n = 0;

         while (names.hasMoreElements()) {

             n++;

         }

         return (n);

     }

     /**

      * Return a Collection view of the values contained in this map.

      */

     public Collection values() {

         ArrayList results = new ArrayList();

         Enumeration names = httpSession.getAttributeNames();

         while (names.hasMoreElements()) {

             String name = (String) names.nextElement();

             results.add(httpSession.getAttribute(name));

         }

         return (results);

     }

 }