SMACK-272 Add support for XEP-0060 (pubsub)

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/trunk@11346 b35dd754-fafc-0310-a699-88a17e54d16e

source/org/jivesoftware/smackx/pubsub/ItemsExtension.java

@@ -0,0 +1,183 @@
+/**
+ * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smackx.pubsub;
+
+import java.util.List;
+
+import org.jivesoftware.smack.packet.PacketExtension;
+
+/**
+ * This class is used to for multiple purposes.  
+ * <li>It can represent an event containing a list of items that have been published
+ * <li>It can represent an event containing a list of retracted (deleted) items.
+ * <li>It can represent a request to delete a list of items.
+ * <li>It can represent a request to get existing items.
+ * 
+ * <p><b>Please note, this class is used for internal purposes, and is not required for usage of 
+ * pubsub functionality.</b>
+ * 
+ * @author Robin Collier
+ */
+public class ItemsExtension extends NodeExtension implements EmbeddedPacketExtension
+{
+	protected ItemsElementType type;
+	protected String attValue;
+	protected List<? extends PacketExtension> items;
+
+	public enum ItemsElementType
+	{
+		/** An items element, which has an optional <b>max_items</b> attribute when requesting items */
+		items(PubSubElementType.ITEMS, "max_items"),
+		
+		/** A retract element, which has an optional <b>notify</b> attribute when publishing deletions */
+		retract(PubSubElementType.RETRACT, "notify");
+		
+		private PubSubElementType elem;
+		private String att;
+		
+		private ItemsElementType(PubSubElementType nodeElement, String attribute)
+		{
+			elem = nodeElement;
+			att = attribute;
+		}
+		
+		public PubSubElementType getNodeElement()
+		{
+			return elem;
+		}
+
+		public String getElementAttribute()
+		{
+			return att;
+		}
+	}
+
+	/**
+	 * Construct an instance with a list representing items that have been published or deleted.
+	 * 
+	 * <p>Valid scenarios are:
+	 * <li>Request items from node - itemsType = {@link ItemsElementType#items}, items = list of {@link Item} and an
+	 * optional value for the <b>max_items</b> attribute.
+	 * <li>Request to delete items - itemsType = {@link ItemsElementType#retract}, items = list of {@link Item} containing
+	 * only id's and an optional value for the <b>notify</b> attribute.
+	 * <li>Items published event - itemsType = {@link ItemsElementType#items}, items = list of {@link Item} and 
+	 * attributeValue = <code>null</code>
+	 * <li>Items deleted event -  itemsType = {@link ItemsElementType#items}, items = list of {@link RetractItem} and 
+	 * attributeValue = <code>null</code> 
+	 * 
+	 * @param itemsType Type of representation
+	 * @param nodeId The node to which the items are being sent or deleted
+	 * @param items The list of {@link Item} or {@link RetractItem}
+	 * @param attributeValue The value of the <b>max_items</b>  
+	 */
+	public ItemsExtension(ItemsElementType itemsType, String nodeId, List<? extends PacketExtension> items, String attributeValue)
+	{
+		super(itemsType.getNodeElement(), nodeId);
+		type = itemsType;
+		this.items = items;
+		attValue = attributeValue;
+	}
+	
+	/**
+	 * Constructs a request to get items from the node as defined in the first scenario
+	 * in {@link #ItemsExtension(ItemsElementType, String, List, String)}
+	 * 
+	 * @param nodeId The node the items will be requested from
+	 * @param maxItems The limit on the number of items to retrieve (null for all)
+	 */
+	public ItemsExtension(String nodeId, Integer maxItems)
+	{
+		this(ItemsElementType.items, nodeId, null, maxItems == null ? null : maxItems.toString());
+	}
+	
+	/**
+	 * Get the type of element
+	 * 
+	 * @return The element type
+	 */
+	public ItemsElementType getItemsElementType()
+	{
+		return type;
+	}
+	
+	public List<PacketExtension> getExtensions()
+	{
+		return (List<PacketExtension>)getItems();
+	}
+	
+	/**
+	 * Gets the items related to the type of request or event.
+	 * 
+	 * return List of {@link Item}, {@link RetractItem}, or null
+	 */
+	public List<? extends PacketExtension> getItems()
+	{
+		return items;
+	}
+
+	/**
+	 * Gets the value of the optional attribute related to the {@link ItemsElementType}.
+	 * 
+	 * @return The attribute value
+	 */
+	public String getAttributeValue()
+	{
+		return attValue;
+	}
+	
+	@Override
+	public String toXML()
+	{
+		if (((items == null) || (items.size() == 0)) && (attValue == null))
+		{
+			return super.toXML();
+		}
+		else
+		{
+			StringBuilder builder = new StringBuilder("<");
+			builder.append(getElementName());
+			builder.append(" node='");
+			builder.append(getNode());
+			
+			if (attValue != null)
+			{
+				builder.append("' ");
+				builder.append(type.getElementAttribute());
+				builder.append("='");
+				builder.append(attValue);
+				builder.append("'>");
+			}
+			else
+			{
+				builder.append("'>");
+				for (PacketExtension item : items)
+				{
+					builder.append(item.toXML());
+				}
+			}
+			
+			builder.append("</");
+			builder.append(getElementName());
+			builder.append(">");
+			return builder.toString();
+		}
+	}
+
+	@Override
+	public String toString()
+	{
+		return getClass().getName() + "Content [" + toXML() + "]";
+	}
+
+}