1/**
2 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
3 * you may not use this file except in compliance with the License.
4 * You may obtain a copy of the License at
5 *
6 *     http://www.apache.org/licenses/LICENSE-2.0
7 *
8 * Unless required by applicable law or agreed to in writing, software
9 * distributed under the License is distributed on an "AS IS" BASIS,
10 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 * See the License for the specific language governing permissions and
12 * limitations under the License.
13 */
14package org.jivesoftware.smackx.pubsub;
15
16import org.jivesoftware.smack.packet.Message;
17import org.jivesoftware.smack.packet.PacketExtension;
18import org.jivesoftware.smackx.pubsub.provider.ItemProvider;
19
20/**
21 * This class represents an item that has been, or will be published to a
22 * pubsub node.  An <tt>Item</tt> has several properties that are dependent
23 * on the configuration of the node to which it has been or will be published.
24 *
25 * <h1>An Item received from a node (via {@link LeafNode#getItems()} or {@link LeafNode#addItemEventListener(org.jivesoftware.smackx.pubsub.listener.ItemEventListener)}</b>
26 * <li>Will always have an id (either user or server generated) unless node configuration has both
27 * {@link ConfigureForm#isPersistItems()} and {@link ConfigureForm#isDeliverPayloads()}set to false.
28 * <li>Will have a payload if the node configuration has {@link ConfigureForm#isDeliverPayloads()} set
29 * to true, otherwise it will be null.
30 *
31 * <h1>An Item created to send to a node (via {@link LeafNode#send()} or {@link LeafNode#publish()}</b>
32 * <li>The id is optional, since the server will generate one if necessary, but should be used if it is
33 * meaningful in the context of the node.  This value must be unique within the node that it is sent to, since
34 * resending an item with the same id will overwrite the one that already exists if the items are persisted.
35 * <li>Will require payload if the node configuration has {@link ConfigureForm#isDeliverPayloads()} set
36 * to true.
37 *
38 * <p>To customise the payload object being returned from the {@link #getPayload()} method, you can
39 * add a custom parser as explained in {@link ItemProvider}.
40 *
41 * @author Robin Collier
42 */
43public class PayloadItem<E extends PacketExtension> extends Item
44{
45	private E payload;
46
47	/**
48	 * Create an <tt>Item</tt> with no id and a payload  The id will be set by the server.
49	 *
50	 * @param payloadExt A {@link PacketExtension} which represents the payload data.
51	 */
52	public PayloadItem(E payloadExt)
53	{
54		super();
55
56		if (payloadExt == null)
57			throw new IllegalArgumentException("payload cannot be 'null'");
58		payload = payloadExt;
59	}
60
61	/**
62	 * Create an <tt>Item</tt> with an id and payload.
63	 *
64	 * @param itemId The id of this item.  It can be null if we want the server to set the id.
65	 * @param payloadExt A {@link PacketExtension} which represents the payload data.
66	 */
67	public PayloadItem(String itemId, E payloadExt)
68	{
69		super(itemId);
70
71		if (payloadExt == null)
72			throw new IllegalArgumentException("payload cannot be 'null'");
73		payload = payloadExt;
74	}
75
76	/**
77	 * Create an <tt>Item</tt> with an id, node id and payload.
78	 *
79	 * <p>
80	 * <b>Note:</b> This is not valid for publishing an item to a node, only receiving from
81	 * one as part of {@link Message}.  If used to create an Item to publish
82	 * (via {@link LeafNode#publish(Item)}, the server <i>may</i> return an
83	 * error for an invalid packet.
84	 *
85	 * @param itemId The id of this item.
86	 * @param nodeId The id of the node the item was published to.
87	 * @param payloadExt A {@link PacketExtension} which represents the payload data.
88	 */
89	public PayloadItem(String itemId, String nodeId, E payloadExt)
90	{
91		super(itemId, nodeId);
92
93		if (payloadExt == null)
94			throw new IllegalArgumentException("payload cannot be 'null'");
95		payload = payloadExt;
96	}
97
98	/**
99	 * Get the payload associated with this <tt>Item</tt>.  Customising the payload
100	 * parsing from the server can be accomplished as described in {@link ItemProvider}.
101	 *
102	 * @return The payload as a {@link PacketExtension}.
103	 */
104	public E getPayload()
105	{
106		return payload;
107	}
108
109	@Override
110	public String toXML()
111	{
112		StringBuilder builder = new StringBuilder("<item");
113
114		if (getId() != null)
115		{
116			builder.append(" id='");
117			builder.append(getId());
118			builder.append("'");
119		}
120
121        if (getNode() != null) {
122            builder.append(" node='");
123            builder.append(getNode());
124            builder.append("'");
125        }
126		builder.append(">");
127		builder.append(payload.toXML());
128		builder.append("</item>");
129
130		return builder.toString();
131	}
132
133	@Override
134	public String toString()
135	{
136		return getClass().getName() + " | Content [" + toXML() + "]";
137	}
138}
139