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      1 /**
      2  * $RCSfile$
      3  * $Revision$
      4  * $Date$
      5  *
      6  * Copyright 2003-2007 Jive Software.
      7  *
      8  * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
      9  * you may not use this file except in compliance with the License.
     10  * You may obtain a copy of the License at
     11  *
     12  *     http://www.apache.org/licenses/LICENSE-2.0
     13  *
     14  * Unless required by applicable law or agreed to in writing, software
     15  * distributed under the License is distributed on an "AS IS" BASIS,
     16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     17  * See the License for the specific language governing permissions and
     18  * limitations under the License.
     19  */
     20 
     21 package org.jivesoftware.smack.packet;
     22 
     23 import java.util.*;
     24 
     25 /**
     26  * Default implementation of the PacketExtension interface. Unless a PacketExtensionProvider
     27  * is registered with {@link org.jivesoftware.smack.provider.ProviderManager ProviderManager},
     28  * instances of this class will be returned when getting packet extensions.<p>
     29  *
     30  * This class provides a very simple representation of an XML sub-document. Each element
     31  * is a key in a Map with its CDATA being the value. For example, given the following
     32  * XML sub-document:
     33  *
     34  * <pre>
     35  * &lt;foo xmlns="http://bar.com"&gt;
     36  *     &lt;color&gt;blue&lt;/color&gt;
     37  *     &lt;food&gt;pizza&lt;/food&gt;
     38  * &lt;/foo&gt;</pre>
     39  *
     40  * In this case, getValue("color") would return "blue", and getValue("food") would
     41  * return "pizza". This parsing mechanism mechanism is very simplistic and will not work
     42  * as desired in all cases (for example, if some of the elements have attributes. In those
     43  * cases, a custom PacketExtensionProvider should be used.
     44  *
     45  * @author Matt Tucker
     46  */
     47 public class DefaultPacketExtension implements PacketExtension {
     48 
     49     private String elementName;
     50     private String namespace;
     51     private Map<String,String> map;
     52 
     53     /**
     54      * Creates a new generic packet extension.
     55      *
     56      * @param elementName the name of the element of the XML sub-document.
     57      * @param namespace the namespace of the element.
     58      */
     59     public DefaultPacketExtension(String elementName, String namespace) {
     60         this.elementName = elementName;
     61         this.namespace = namespace;
     62     }
     63 
     64      /**
     65      * Returns the XML element name of the extension sub-packet root element.
     66      *
     67      * @return the XML element name of the packet extension.
     68      */
     69     public String getElementName() {
     70         return elementName;
     71     }
     72 
     73     /**
     74      * Returns the XML namespace of the extension sub-packet root element.
     75      *
     76      * @return the XML namespace of the packet extension.
     77      */
     78     public String getNamespace() {
     79         return namespace;
     80     }
     81 
     82     public String toXML() {
     83         StringBuilder buf = new StringBuilder();
     84         buf.append("<").append(elementName).append(" xmlns=\"").append(namespace).append("\">");
     85         for (String name : getNames()) {
     86             String value = getValue(name);
     87             buf.append("<").append(name).append(">");
     88             buf.append(value);
     89             buf.append("</").append(name).append(">");
     90         }
     91         buf.append("</").append(elementName).append(">");
     92         return buf.toString();
     93     }
     94 
     95     /**
     96      * Returns an unmodifiable collection of the names that can be used to get
     97      * values of the packet extension.
     98      *
     99      * @return the names.
    100      */
    101     public synchronized Collection<String> getNames() {
    102         if (map == null) {
    103             return Collections.emptySet();
    104         }
    105         return Collections.unmodifiableSet(new HashMap<String,String>(map).keySet());
    106     }
    107 
    108     /**
    109      * Returns a packet extension value given a name.
    110      *
    111      * @param name the name.
    112      * @return the value.
    113      */
    114     public synchronized String getValue(String name) {
    115         if (map == null) {
    116             return null;
    117         }
    118         return map.get(name);
    119     }
    120 
    121     /**
    122      * Sets a packet extension value using the given name.
    123      *
    124      * @param name the name.
    125      * @param value the value.
    126      */
    127     public synchronized void setValue(String name, String value) {
    128         if (map == null) {
    129             map = new HashMap<String,String>();
    130         }
    131         map.put(name, value);
    132     }
    133 }