implement node addition and removal events
[jSite2.git] / src / net / pterodactylus / jsite / core / NodeManager.java
index 84867cd..b919cfe 100644 (file)
@@ -29,6 +29,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
@@ -39,17 +40,18 @@ import java.util.logging.Logger;
 import net.pterodactylus.fcp.highlevel.HighLevelClient;
 import net.pterodactylus.fcp.highlevel.HighLevelClientListener;
 import net.pterodactylus.util.io.Closer;
+import net.pterodactylus.util.logging.Logging;
 
 /**
  * TODO
- *
+ * 
  * @author David ‘Bombe’ Roden <bombe@freenetproject.org>
  * @version $Id$
  */
-public class NodeManager implements HighLevelClientListener {
+public class NodeManager implements Iterable<Node>, HighLevelClientListener {
 
        /** Logger. */
-       private static final Logger logger = Logger.getLogger(NodeManager.class.getName());
+       private static final Logger logger = Logging.getLogger(NodeManager.class.getName());
 
        /** The FCP client name. */
        private final String clientName;
@@ -77,7 +79,7 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Creates a new FCP collector.
-        *
+        * 
         * @param clientName
         *            The name of the FCP client
         * @param directory
@@ -94,7 +96,7 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Adds the given listener to the list of listeners.
-        *
+        * 
         * @param nodeListener
         *            The listener to add
         */
@@ -104,7 +106,7 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Removes the given listener from the list of listeners.
-        *
+        * 
         * @param nodeListener
         *            The listener to remove
         */
@@ -113,8 +115,32 @@ public class NodeManager implements HighLevelClientListener {
        }
 
        /**
+        * Notifies all listeners that a node was added.
+        * 
+        * @param node
+        *            The node that was added.
+        */
+       private void fireNodeAdded(Node node) {
+               for (NodeListener nodeListener: nodeListeners) {
+                       nodeListener.nodeAdded(node);
+               }
+       }
+
+       /**
+        * Notifies all listeners that a node was removed.
+        * 
+        * @param node
+        *            The node that was removed
+        */
+       private void fireNodeRemoved(Node node) {
+               for (NodeListener nodeListener: nodeListeners) {
+                       nodeListener.nodeRemoved(node);
+               }
+       }
+
+       /**
         * Notifies all listeners that the given node was connected.
-        *
+        * 
         * @param node
         *            The node that is now connected
         */
@@ -126,7 +152,7 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Notifies all listeners that the given node was disconnected.
-        *
+        * 
         * @param node
         *            The node that is now disconnected
         * @param throwable
@@ -145,7 +171,7 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Returns the directory in which the nodes are stored.
-        *
+        * 
         * @return The directory the nodes are stored in
         */
        public String getDirectory() {
@@ -154,7 +180,7 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Checks whether the given node is already connected.
-        *
+        * 
         * @param node
         *            The node to check
         * @return <code>true</code> if the node is already connected,
@@ -164,13 +190,20 @@ public class NodeManager implements HighLevelClientListener {
                return nodes.contains(node);
        }
 
+       /**
+        * {@inheritDoc}
+        */
+       public Iterator<Node> iterator() {
+               return nodes.iterator();
+       }
+
        //
        // ACTIONS
        //
 
        /**
         * Loads nodes.
-        *
+        * 
         * @throws IOException
         *             if an I/O error occurs loading the nodes
         */
@@ -221,15 +254,19 @@ public class NodeManager implements HighLevelClientListener {
                        newNode.setPort(nodePort);
                        loadedNodes.add(newNode);
                }
+               logger.fine("loaded " + loadedNodes.size() + " nodes from config");
                synchronized (syncObject) {
                        nodes.clear();
                        nodes.addAll(loadedNodes);
                }
+               for (Node node: nodes) {
+                       fireNodeAdded(node);
+               }
        }
 
        /**
         * Saves all configured nodes.
-        *
+        * 
         * @throws IOException
         *             if an I/O error occurs saving the nodes
         */
@@ -260,7 +297,7 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Adds the given node to this manager.
-        *
+        * 
         * @see #connect(Node)
         * @param node
         *            The node to connect to
@@ -269,6 +306,7 @@ public class NodeManager implements HighLevelClientListener {
                synchronized (syncObject) {
                        if (!nodes.contains(node)) {
                                nodes.add(node);
+                               fireNodeAdded(node);
                        }
                }
        }
@@ -276,7 +314,7 @@ public class NodeManager implements HighLevelClientListener {
        /**
         * Removes the given node from the node manager, disconnecting it if it is
         * currently connected.
-        *
+        * 
         * @param node
         *            The node to remove
         */
@@ -288,12 +326,13 @@ public class NodeManager implements HighLevelClientListener {
                        if (nodeClients.containsKey(node)) {
                                disconnect(node);
                        }
+                       fireNodeRemoved(node);
                }
        }
 
        /**
         * Tries to establish a connection with the given node.
-        *
+        * 
         * @param node
         *            The node to connect to
         */
@@ -313,7 +352,7 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Disconnects the given node without removing it.
-        *
+        * 
         * @param node
         *            The node to disconnect
         */
@@ -329,13 +368,63 @@ public class NodeManager implements HighLevelClientListener {
 
        /**
         * Returns a list of all nodes.
-        *
+        * 
         * @return A list of all nodes
         */
        public List<Node> getNodes() {
                return Collections.unmodifiableList(nodes);
        }
 
+       /**
+        * “Borrows” a high-level client for the given node. A borrowed client
+        * <strong>has</strong> to be returned to the node manager using
+        * {@link #returnHighLevelClient(HighLevelClient)} when it is no longer in
+        * use, i.e. after a message has been sent! This method will block until a
+        * high-level client for the given node is available.
+        * 
+        * @param node
+        *            The node to get a high-level client for
+        * @return The high-level client for a node, or <code>null</code> if the
+        *         node was disconnected or removed
+        */
+       public HighLevelClient borrowHighLevelClient(Node node) {
+               synchronized (syncObject) {
+                       if (!nodeClients.containsKey(node)) {
+                               return null;
+                       }
+                       HighLevelClient highLevelClient = nodeClients.get(node);
+                       while (nodeClients.containsKey(node) && usedConnections.contains(highLevelClient)) {
+                               try {
+                                       syncObject.wait();
+                               } catch (InterruptedException ie1) {
+                                       /* ignore. TODO - check. */
+                               }
+                       }
+                       if (!nodeClients.containsKey(node)) {
+                               return null;
+                       }
+                       usedConnections.add(highLevelClient);
+                       return highLevelClient;
+               }
+       }
+
+       /**
+        * Returns a borrowed high-level client.
+        * 
+        * @see #borrowHighLevelClient(Node)
+        * @param highLevelClient
+        *            The high-level client to return
+        */
+       public void returnHighLevelClient(HighLevelClient highLevelClient) {
+               synchronized (syncObject) {
+                       if (!clientNodes.containsKey(highLevelClient)) {
+                               return;
+                       }
+                       usedConnections.remove(highLevelClient);
+                       syncObject.notifyAll();
+               }
+       }
+
        //
        // PRIVATE METHODS
        //
@@ -343,7 +432,7 @@ public class NodeManager implements HighLevelClientListener {
        /**
         * Finds a currently unused high-level client, optionally waiting until a
         * client is free and marking it used.
-        *
+        * 
         * @param wait
         *            <code>true</code> to wait for a free connection,
         *            <code>false</code> to return <code>null</code>
@@ -373,6 +462,11 @@ public class NodeManager implements HighLevelClientListener {
                                if (!wait) {
                                        return null;
                                }
+                               try {
+                                       syncObject.wait();
+                               } catch (InterruptedException e) {
+                                       /* ignore, just re-check. */
+                               }
                        }
                        /* we never get here, but the compiler doesn't realize. */
                        return null;
@@ -387,6 +481,7 @@ public class NodeManager implements HighLevelClientListener {
         * {@inheritDoc}
         */
        public void clientConnected(HighLevelClient highLevelClient) {
+               logger.log(Level.FINER, "clientConnected(c=" + highLevelClient + ")");
                Node node = clientNodes.get(highLevelClient);
                if (node == null) {
                        logger.log(Level.WARNING, "got event for unknown client");
@@ -399,6 +494,7 @@ public class NodeManager implements HighLevelClientListener {
         * {@inheritDoc}
         */
        public void clientDisconnected(HighLevelClient highLevelClient, Throwable throwable) {
+               logger.log(Level.FINER, "clientDisconnected(c=" + highLevelClient + ",t=" + throwable + ")");
                synchronized (syncObject) {
                        Node node = clientNodes.remove(highLevelClient);
                        if (node == null) {
@@ -406,6 +502,7 @@ public class NodeManager implements HighLevelClientListener {
                                return;
                        }
                        nodeClients.remove(node);
+                       usedConnections.remove(highLevelClient);
                        fireNodeDisconnected(node, throwable);
                }
        }