/*

  * $Id: BasicMessageList.java 366395 2006-01-06 02:42:19Z niallp $

  * $Revision: 366395 $

  * $Date: 2006-01-06 02:42:19 +0000 (Fri, 06 Jan 2006) $

  *

  * ====================================================================

  *

  *  Copyright 2003-2006 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.resources.impl;

 import java.io.Serializable;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.Comparator;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.List;

 import java.util.Map;

 import org.apache.commons.resources.Message;

 import org.apache.commons.resources.MessageList;

 /**

  * A basic implementation of a MessageList.

  * <p>

  * Orginally based on org.apache.struts.action.ActionMessages, Revision 49670.

  */

 public class BasicMessageList implements Serializable, MessageList {

     /**

      * Compares MessageItems.

      */

     private static final Comparator ACTION_ITEM_COMPARATOR = new Comparator() {

         public int compare(Object o1, Object o2) {

             return ((MessageItem) o1).getOrder() - ((MessageItem) o2).getOrder();

         }

     };

     /**

      * Have the messages been retrieved from this object?

      */

     private boolean accessed = false;

     /**

      * The accumulated set of <code>Message</code> objects (represented

      * as a List) for each property, keyed by property name.

      */

     private Map messages = new HashMap();

     /**

      * The current number of the property/key being added.  This is used

      * to maintain the order messages are added.

      */

     private int count = 0;

     // --------------------------------------------------------- Public Methods

     /**

      * Create an empty <code>MessageList</code> object.

      */

     public BasicMessageList() {

         super();

     }

     /**

      * Create an <code>MessageList</code> object initialized to use

      * the given value for the "global" message key.

      *

      * @param globalMessageKey The new default global message key

      */

     public BasicMessageList(String globalMessageKey) {

         super();

         this.setGlobalMessageKey(globalMessageKey);

     }

     /**

      * Create an <code>MessageList</code> object initialized with the given

      * messages.

      *

      * @param messages The messages to be initially added to this object.

      */

     public BasicMessageList(MessageList messages) {

         super();

         this.add(messages);

     }

     /**

      * Create an <code>MessageList</code> object initialized with the given

      * messages and the given global message key.

      *

      * @param globalMessageKey The new default global message key

      * @param messages The messages to be initially added to this object.

      * 

      */

     public BasicMessageList(String globalMessageKey, MessageList messages) {

         super();

         this.setGlobalMessageKey(globalMessageKey);

         this.add(messages);

     }

     /**

      * The "global" message key for this MessageList

      * [GLOBAL_MESSAGE_KEY].

      */

     private String globalMessageKey = GLOBAL_MESSAGE_KEY;

     /**

      * @return The default global message key

      */

     public String getGlobalMessageKey() {

         return this.globalMessageKey;

     }

     /**

      * @param globalMessageKey The new default global message key

      */

     public void setGlobalMessageKey(String globalMessageKey) {

         this.globalMessageKey = globalMessageKey;

     }

     /**

      * Add a message to the set of messages for the specified property.  An

      * order of the property/key is maintained based on the initial addition

      * of the property/key.

      *

      * @param property  Property name (or MessageList.GLOBAL_MESSAGE_KEY)

      * @param message   The message to be added

      */

     public void add(String property, Message message) {

         MessageItem item = (MessageItem) messages.get(property);

         List list = null;

         if (item == null) {

             list = new ArrayList();

             item = new MessageItem(list, this.count++);

             messages.put(property, item);

         } else {

             list = item.getList();

         }

         list.add(message);

     }

     /**

      * Add a message to the set of messages for the "global" property.  An

      * order of the property/key is maintained based on the initial addition

      * of the property/key.

      *

      * @param message   The message to be added

      */

     public void add(Message message) {

         this.add(getGlobalMessageKey(), message);

     }

     /**

      * Adds the messages from the given <code>MessageList</code> object to

      * this set of messages. The messages are added in the order they are returned from

      * the properties() method. If a message's property is already in the current

      * <code>MessageList</code> object it is added to the end of the list for that

      * property. If a message's property is not in the current list it is added to the end

      * of the properties.

      *

      * @param messageList The <code>MessageList</code> object to be added.

      */

     public void add(MessageList messageList) {

         // loop over properties

         Iterator props = messageList.properties();

         while (props.hasNext()) {

             String property = (String) props.next();

             // loop over messages for each property

             Iterator msgs = messageList.get(property);

             while (msgs.hasNext()) {

                 Message msg = (Message) msgs.next();

                 this.add(property, msg);

             }

         }

     }

     /**

      * Clear all messages recorded by this object.

      */

     public void clear() {

         this.messages.clear();

     }

     /**

      * Determines if the MessageList's messages have been accessed one or more

      * times.  Returns <code>true</code> if the <code>get()</code> or 

      * <code>get(String)</code> methods are called.  

      * @return <code>true</code> if the messages have been accessed one or more

      * times.

      */

     public boolean isAccessed() {

         return this.accessed;

     }

     /**

      * @return Return <code>true</code> if there are no messages recorded

      * in this collection, or <code>false</code> otherwise.

      */

     public boolean isEmpty() {

         return messages.isEmpty();

     }

     /**

      * Return the set of all recorded messages, without distinction

      * by which property the messages are associated with.  If there are

      * no messages recorded, an empty enumeration is returned.

      *

      * @return All messages.

      */

     public Iterator get() {

         this.accessed = true;

         if (messages.isEmpty()) {

             return Collections.EMPTY_LIST.iterator();

         }

         ArrayList results = new ArrayList();

         ArrayList actionItems = new ArrayList();

         for (Iterator i = messages.values().iterator(); i.hasNext();) {

             actionItems.add(i.next());

         }

         // Sort MessageItems based on the initial order the

         // property/key was added to MessageList.

         Collections.sort(actionItems, ACTION_ITEM_COMPARATOR);

         for (Iterator i = actionItems.iterator(); i.hasNext();) {

             MessageItem ami = (MessageItem) i.next();

             for (Iterator msgs = ami.getList().iterator(); msgs.hasNext();) {

                 results.add(msgs.next());

             }

         }

         return results.iterator();

     }

     /**

      * Return the set of messages related to a specific property.

      * If there are no such messages, an empty enumeration is returned.

      *

      * @param property Property name

      * @return Messages related to a specific property.

      */

     public Iterator get(String property) {

         this.accessed = true;

         MessageItem item = (MessageItem) messages.get(property);

         return (item == null)

             ? Collections.EMPTY_LIST.iterator()

             : item.getList().iterator();

     }

     /**

      * Return the set of property names for which at least one message has

      * been recorded.  If there are no messages, an empty Iterator is returned.

      * If you have recorded global messages, the String value of

      * <code>MessageList.GLOBAL_MESSAGE</code> will be one of the returned

      * property names.

      *

      * @return The property names.

      */

     public Iterator properties() {

         return messages.keySet().iterator();

     }

     /**

      * Return the number of messages recorded for all properties (including

      * global messages).  <strong>NOTE</strong> - it is more efficient to call

      * <code>isEmpty()</code> if all you care about is whether or not there are

      * any messages at all.

      *

      * @return The number of messages.

      */

     public int size() {

         int total = 0;

         for (Iterator i = messages.values().iterator(); i.hasNext();) {

             MessageItem ami = (MessageItem) i.next();

             total += ami.getList().size();

         }

         return total;

     }

     /**

      * Return the number of messages associated with the specified property.

      *

      * @param property Property name (or MessageList.GLOBAL_MESSAGE_KEY

      * @return The number of messages for a specific property.

      */

     public int size(String property) {

         MessageItem ami = (MessageItem) messages.get(property);

         return (ami == null) ? 0 : ami.getList().size();

     }

     /**

      * Returns a String representation of this MessageList's 

      * [property name]=[message list] mapping.

      * @see java.lang.Object#toString()

      */    

     public String toString() {

         return this.messages.toString();

     }

     /**

      * Holds messages for a specified property.

      */    

     protected static class MessageItem implements Serializable {

         /**

          * The list of <code>Message</code>s.

          */

         private List list = null;

         /**

          * The position in the list of messages.

          */

         private int order = 0;

         /**

          * Construct a MessageItem with a list of messages

          * and specified order.

          * @param list List of Messages.

          * @param order Order.

          */

         public MessageItem(List list, int order) {

             this.list = list;

             this.order = order;

         }

         /**

          * @return The list of messsages.

          */

         public List getList() {

             return list;

         }

         /**

          * @param list The list of messsages.

          */

         public void setList(List list) {

             this.list = list;

         }

         /**

          * @return The order.

          */

         public int getOrder() {

             return order;

         }

         /**

          * @param order The order.

          */

         public void setOrder(int order) {

             this.order = order;

         }

     }

 }