1 files changed, 123 insertions, 0 deletions
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AcceptorLoop.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AcceptorLoop.java
new file mode 100644
index 00000000..e416f3be
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AcceptorLoop.java
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * 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.onlab.nio;
+
+import java.io.IOException;
+import java.net.SocketAddress;
+import java.net.StandardSocketOptions;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.ServerSocketChannel;
+import java.util.Iterator;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Selector loop derivative tailored to acceptConnection inbound connections.
+ */
+public abstract class AcceptorLoop extends SelectorLoop {
+
+    private SocketAddress listenAddress;
+    private ServerSocketChannel socketChannel;
+
+    /**
+     * Creates an acceptor loop with the specified selection timeout and
+     * accepting connections on the the given address.
+     *
+     * @param selectTimeout selection timeout; specified in millis
+     * @param listenAddress socket address where to listen for connections
+     * @throws IOException if the backing selector cannot be opened
+     */
+    public AcceptorLoop(long selectTimeout, SocketAddress listenAddress)
+            throws IOException {
+        super(selectTimeout);
+        this.listenAddress = checkNotNull(listenAddress, "Address cannot be null");
+    }
+
+    /**
+     * Hook to accept an inbound connection on the specified socket channel.
+     *
+     * @param channel socketChannel where an accept operation awaits
+     * @throws IOException if the accept operation cannot be processed
+     */
+    protected abstract void acceptConnection(ServerSocketChannel channel) throws IOException;
+
+    /**
+     * Opens a new server socket channel configured in non-blocking mode and
+     * bound to the loop's listen address.
+     *
+     * @throws IOException if unable to open or configure the socket channel
+     */
+    protected synchronized void openChannel() throws IOException {
+        socketChannel = ServerSocketChannel.open();
+        socketChannel.configureBlocking(false);
+        socketChannel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
+        socketChannel.register(selector, SelectionKey.OP_ACCEPT);
+        socketChannel.bind(listenAddress);
+    }
+
+    /**
+     * Closes the server socket channel.
+     *
+     * @throws IOException if unable to close the socketChannel
+     */
+    protected synchronized void closechannel() throws IOException {
+        if (socketChannel != null) {
+            socketChannel.close();
+            socketChannel = null;
+        }
+    }
+
+    @Override
+    public void shutdown() {
+        try {
+            closechannel();
+        } catch (IOException e) {
+            log.warn("Unable to close the socketChannel", e);
+        }
+        super.shutdown();
+    }
+
+    @Override
+    protected void loop() throws IOException {
+        openChannel();
+        notifyReady();
+
+        // Keep looping until told otherwise.
+        while (isRunning()) {
+            // Attempt a selection; if no operations selected or if signalled
+            // to shutdown, spin through.
+            int count = selector.select(selectTimeout);
+            if (count == 0 || !isRunning()) {
+                continue;
+            }
+
+            // Iterate over all keys selected for an operation and process them.
+            Iterator<SelectionKey> keys = selector.selectedKeys().iterator();
+            while (keys.hasNext()) {
+                // Fetch the key and remove it from the pending list.
+                SelectionKey key = keys.next();
+                keys.remove();
+
+                // If the key has a pending acceptConnection operation, process it.
+                if (key.isAcceptable()) {
+                    acceptConnection((ServerSocketChannel) key.channel());
+                }
+            }
+        }
+    }
+
+}
+