Move protocol framework from BGPCEP project

[controller.git] / opendaylight / commons / protocol-framework / src / main / java / org / opendaylight / protocol / framework / AbstractSessionNegotiator.java

diff --git a/opendaylight/commons/protocol-framework/src/main/java/org/opendaylight/protocol/framework/AbstractSessionNegotiator.java b/opendaylight/commons/protocol-framework/src/main/java/org/opendaylight/protocol/framework/AbstractSessionNegotiator.java
new file mode 100644 (file)
index 0000000..9ecfb1b
--- /dev/null
+++ b/opendaylight/commons/protocol-framework/src/main/java/org/opendaylight/protocol/framework/AbstractSessionNegotiator.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.protocol.framework;
+
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.util.concurrent.Promise;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * Abstract base class for session negotiators. It implements the basic
+ * substrate to implement SessionNegotiator API specification, with subclasses
+ * needing to provide only
+ *
+ * @param <M> Protocol message type
+ * @param <S> Protocol session type, has to extend ProtocolSession<M>
+ */
+public abstract class AbstractSessionNegotiator<M, S extends AbstractProtocolSession<?>> extends ChannelInboundHandlerAdapter implements SessionNegotiator<S> {
+    private final Logger logger = LoggerFactory.getLogger(AbstractSessionNegotiator.class);
+    private final Promise<S> promise;
+    protected final Channel channel;
+
+    public AbstractSessionNegotiator(final Promise<S> promise, final Channel channel) {
+        this.promise = Preconditions.checkNotNull(promise);
+        this.channel = Preconditions.checkNotNull(channel);
+    }
+
+    protected abstract void startNegotiation() throws Exception;
+    protected abstract void handleMessage(M msg) throws Exception;
+
+    protected final void negotiationSuccessful(final S session) {
+        logger.debug("Negotiation on channel {} successful with session {}", channel, session);
+        channel.pipeline().replace(this, "session", session);
+        promise.setSuccess(session);
+    }
+
+    protected final void negotiationFailed(final Throwable cause) {
+        logger.debug("Negotiation on channel {} failed", channel, cause);
+        channel.close();
+        promise.setFailure(cause);
+    }
+
+    @Override
+    public final void channelActive(final ChannelHandlerContext ctx) {
+        logger.debug("Starting session negotiation on channel {}", channel);
+        try {
+            startNegotiation();
+        } catch (Exception e) {
+            logger.info("Unexpected negotiation failure", e);
+            negotiationFailed(e);
+        }
+    }
+
+    @Override
+    public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
+        logger.debug("Negotiation read invoked on channel {}", channel);
+        try {
+            handleMessage((M)msg);
+        } catch (Exception e) {
+            logger.debug("Unexpected exception during negotiation", e);
+            negotiationFailed(e);
+        }
+    }
+}