Shuyi Chen | d7955ce | 2013-05-22 14:51:55 -0700 | [diff] [blame] | 1 | /**
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| 2 | * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
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| 3 | * you may not use this file except in compliance with the License.
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| 4 | * You may obtain a copy of the License at
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| 5 | *
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| 6 | * http://www.apache.org/licenses/LICENSE-2.0
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| 7 | *
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| 8 | * Unless required by applicable law or agreed to in writing, software
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| 9 | * distributed under the License is distributed on an "AS IS" BASIS,
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| 10 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 11 | * See the License for the specific language governing permissions and
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| 12 | * limitations under the License.
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| 13 | */
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| 14 |
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| 15 | package org.jivesoftware.smack.provider;
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| 16 |
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| 17 | import java.util.ArrayList;
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| 18 | import java.util.HashMap;
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| 19 | import java.util.List;
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| 20 | import java.util.Map;
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| 21 |
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| 22 | import org.jivesoftware.smack.packet.PacketExtension;
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| 23 | import org.jivesoftware.smack.provider.PacketExtensionProvider;
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| 24 | import org.jivesoftware.smack.util.PacketParserUtils;
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| 25 | import org.jivesoftware.smackx.pubsub.provider.ItemProvider;
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| 26 | import org.jivesoftware.smackx.pubsub.provider.ItemsProvider;
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| 27 | import org.xmlpull.v1.XmlPullParser;
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| 28 |
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| 29 | /**
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| 30 | *
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| 31 | * This class simplifies parsing of embedded elements by using the
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| 32 | * <a href="http://en.wikipedia.org/wiki/Template_method_pattern">Template Method Pattern</a>.
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| 33 | * After extracting the current element attributes and content of any child elements, the template method
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| 34 | * ({@link #createReturnExtension(String, String, Map, List)} is called. Subclasses
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| 35 | * then override this method to create the specific return type.
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| 36 | *
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| 37 | * <p>To use this class, you simply register your subclasses as extension providers in the
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| 38 | * <b>smack.properties</b> file. Then they will be automatically picked up and used to parse
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| 39 | * any child elements.
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| 40 | *
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| 41 | * <pre>
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| 42 | * For example, given the following message
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| 43 | *
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| 44 | * <message from='pubsub.shakespeare.lit' to='francisco@denmark.lit' id='foo>
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| 45 | * <event xmlns='http://jabber.org/protocol/pubsub#event>
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| 46 | * <items node='princely_musings'>
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| 47 | * <item id='asdjkwei3i34234n356'>
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| 48 | * <entry xmlns='http://www.w3.org/2005/Atom'>
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| 49 | * <title>Soliloquy</title>
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| 50 | * <link rel='alternative' type='text/html'/>
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| 51 | * <id>tag:denmark.lit,2003:entry-32397</id>
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| 52 | * </entry>
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| 53 | * </item>
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| 54 | * </items>
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| 55 | * </event>
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| 56 | * </message>
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| 57 | *
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| 58 | * I would have a classes
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| 59 | * {@link ItemsProvider} extends {@link EmbeddedExtensionProvider}
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| 60 | * {@link ItemProvider} extends {@link EmbeddedExtensionProvider}
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| 61 | * and
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| 62 | * AtomProvider extends {@link PacketExtensionProvider}
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| 63 | *
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| 64 | * These classes are then registered in the meta-inf/smack.providers file
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| 65 | * as follows.
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| 66 | *
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| 67 | * <extensionProvider>
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| 68 | * <elementName>items</elementName>
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| 69 | * <namespace>http://jabber.org/protocol/pubsub#event</namespace>
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| 70 | * <className>org.jivesoftware.smackx.provider.ItemsEventProvider</className>
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| 71 | * </extensionProvider>
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| 72 | * <extensionProvider>
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| 73 | * <elementName>item</elementName>
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| 74 | * <namespace>http://jabber.org/protocol/pubsub#event</namespace>
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| 75 | * <className>org.jivesoftware.smackx.provider.ItemProvider</className>
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| 76 | * </extensionProvider>
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| 77 | *
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| 78 | * </pre>
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| 79 | *
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| 80 | * @author Robin Collier
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| 81 | */
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| 82 | abstract public class EmbeddedExtensionProvider implements PacketExtensionProvider
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| 83 | {
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| 84 |
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| 85 | final public PacketExtension parseExtension(XmlPullParser parser) throws Exception
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| 86 | {
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| 87 | String namespace = parser.getNamespace();
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| 88 | String name = parser.getName();
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| 89 | Map<String, String> attMap = new HashMap<String, String>();
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| 90 |
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| 91 | for(int i=0; i<parser.getAttributeCount(); i++)
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| 92 | {
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| 93 | attMap.put(parser.getAttributeName(i), parser.getAttributeValue(i));
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| 94 | }
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| 95 | List<PacketExtension> extensions = new ArrayList<PacketExtension>();
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| 96 |
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| 97 | do
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| 98 | {
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| 99 | int tag = parser.next();
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| 100 |
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| 101 | if (tag == XmlPullParser.START_TAG)
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| 102 | extensions.add(PacketParserUtils.parsePacketExtension(parser.getName(), parser.getNamespace(), parser));
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| 103 | } while (!name.equals(parser.getName()));
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| 104 |
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| 105 | return createReturnExtension(name, namespace, attMap, extensions);
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| 106 | }
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| 107 |
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| 108 | abstract protected PacketExtension createReturnExtension(String currentElement, String currentNamespace, Map<String, String> attributeMap, List<? extends PacketExtension> content);
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| 109 | }
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