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
21package org.jivesoftware.smack.packet;
22
23import 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 */
47public 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}