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 | package org.jivesoftware.smackx.pubsub;
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| 15 |
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| 16 | import org.jivesoftware.smack.packet.Message;
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| 17 | import org.jivesoftware.smackx.pubsub.provider.ItemProvider;
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| 18 |
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| 19 | /**
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| 20 | * This class represents an item that has been, or will be published to a
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| 21 | * pubsub node. An <tt>Item</tt> has several properties that are dependent
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| 22 | * on the configuration of the node to which it has been or will be published.
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| 23 | *
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| 24 | * <h1>An Item received from a node (via {@link LeafNode#getItems()} or {@link LeafNode#addItemEventListener(org.jivesoftware.smackx.pubsub.listener.ItemEventListener)}</b>
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| 25 | * <li>Will always have an id (either user or server generated) unless node configuration has both
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| 26 | * {@link ConfigureForm#isPersistItems()} and {@link ConfigureForm#isDeliverPayloads()}set to false.
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| 27 | * <li>Will have a payload if the node configuration has {@link ConfigureForm#isDeliverPayloads()} set
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| 28 | * to true, otherwise it will be null.
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| 29 | *
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| 30 | * <h1>An Item created to send to a node (via {@link LeafNode#send()} or {@link LeafNode#publish()}</b>
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| 31 | * <li>The id is optional, since the server will generate one if necessary, but should be used if it is
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| 32 | * meaningful in the context of the node. This value must be unique within the node that it is sent to, since
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| 33 | * resending an item with the same id will overwrite the one that already exists if the items are persisted.
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| 34 | * <li>Will require payload if the node configuration has {@link ConfigureForm#isDeliverPayloads()} set
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| 35 | * to true.
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| 36 | *
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| 37 | * <p>To customise the payload object being returned from the {@link #getPayload()} method, you can
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| 38 | * add a custom parser as explained in {@link ItemProvider}.
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| 39 | *
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| 40 | * @author Robin Collier
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| 41 | */
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| 42 | public class Item extends NodeExtension
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| 43 | {
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| 44 | private String id;
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| 45 |
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| 46 | /**
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| 47 | * Create an empty <tt>Item</tt> with no id. This is a valid item for nodes which are configured
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| 48 | * so that {@link ConfigureForm#isDeliverPayloads()} is false. In most cases an id will be generated by the server.
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| 49 | * For nodes configured with {@link ConfigureForm#isDeliverPayloads()} and {@link ConfigureForm#isPersistItems()}
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| 50 | * set to false, no <tt>Item</tt> is sent to the node, you have to use {@link LeafNode#send()} or {@link LeafNode#publish()}
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| 51 | * methods in this case.
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| 52 | */
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| 53 | public Item()
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| 54 | {
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| 55 | super(PubSubElementType.ITEM);
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| 56 | }
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| 57 |
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| 58 | /**
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| 59 | * Create an <tt>Item</tt> with an id but no payload. This is a valid item for nodes which are configured
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| 60 | * so that {@link ConfigureForm#isDeliverPayloads()} is false.
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| 61 | *
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| 62 | * @param itemId The id if the item. It must be unique within the node unless overwriting and existing item.
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| 63 | * Passing null is the equivalent of calling {@link #Item()}.
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| 64 | */
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| 65 | public Item(String itemId)
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| 66 | {
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| 67 | // The element type is actually irrelevant since we override getNamespace() to return null
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| 68 | super(PubSubElementType.ITEM);
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| 69 | id = itemId;
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| 70 | }
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| 71 |
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| 72 | /**
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| 73 | * Create an <tt>Item</tt> with an id and a node id.
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| 74 | * <p>
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| 75 | * <b>Note:</b> This is not valid for publishing an item to a node, only receiving from
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| 76 | * one as part of {@link Message}. If used to create an Item to publish
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| 77 | * (via {@link LeafNode#publish(Item)}, the server <i>may</i> return an
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| 78 | * error for an invalid packet.
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| 79 | *
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| 80 | * @param itemId The id of the item.
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| 81 | * @param nodeId The id of the node which the item was published to.
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| 82 | */
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| 83 | public Item(String itemId, String nodeId)
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| 84 | {
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| 85 | super(PubSubElementType.ITEM_EVENT, nodeId);
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| 86 | id = itemId;
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| 87 | }
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| 88 |
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| 89 | /**
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| 90 | * Get the item id. Unique to the node it is associated with.
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| 91 | *
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| 92 | * @return The id
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| 93 | */
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| 94 | public String getId()
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| 95 | {
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| 96 | return id;
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| 97 | }
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| 98 |
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| 99 | @Override
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| 100 | public String getNamespace()
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| 101 | {
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| 102 | return null;
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| 103 | }
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| 104 |
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| 105 | @Override
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| 106 | public String toXML()
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| 107 | {
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| 108 | StringBuilder builder = new StringBuilder("<item");
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| 109 |
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| 110 | if (id != null)
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| 111 | {
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| 112 | builder.append(" id='");
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| 113 | builder.append(id);
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| 114 | builder.append("'");
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| 115 | }
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| 116 |
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| 117 | if (getNode() != null) {
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| 118 | builder.append(" node='");
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| 119 | builder.append(getNode());
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| 120 | builder.append("'");
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| 121 | }
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| 122 | builder.append("/>");
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| 123 |
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| 124 | return builder.toString();
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| 125 | }
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| 126 |
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| 127 | @Override
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| 128 | public String toString()
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| 129 | {
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| 130 | return getClass().getName() + " | Content [" + toXML() + "]";
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| 131 | }
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| 132 | }
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