Add support for turning on tcp keep alive.

Change-Id: Ic561f87fe262782a607e86ac8b2e0efb69d2c46e
Reviewed-on: http://review.couchbase.org/81810
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Tested-by: Matt Ingenthron <matt@couchbase.com>

Author: youngm

src/main/java/net/spy/memcached/ConnectionFactory.java

@@ -124,6 +124,15 @@ MemcachedNode createMemcachedNode(SocketAddress sa, SocketChannel c,
    */
   boolean useNagleAlgorithm();
 
+  /**
+   * If true, keep alive will be used on connected sockets.
+   *
+   * <p>
+   * See {@link java.net.Socket#setKeepAlive(boolean)} for more information.
+   * </p>
+   */
+   boolean getKeepAlive();
+
   /**
    * Observers that should be established at the time of connection
    * instantiation.

src/main/java/net/spy/memcached/ConnectionFactoryBuilder.java

@@ -61,6 +61,7 @@ public class ConnectionFactoryBuilder {
   protected boolean isDaemon = false;
   protected boolean shouldOptimize = false;
   protected boolean useNagle = false;
+  protected boolean keepAlive = false;
   protected long maxReconnectDelay =
       DefaultConnectionFactory.DEFAULT_MAX_RECONNECT_DELAY;
 
@@ -222,6 +223,11 @@ public ConnectionFactoryBuilder setUseNagleAlgorithm(boolean to) {
     return this;
   }
 
+  public ConnectionFactoryBuilder setKeepAlive(boolean on) {
+    keepAlive = on;
+    return this;
+  }
+
   /**
    * Convenience method to specify the protocol to use.
    */
@@ -400,6 +406,10 @@ public boolean shouldOptimize() {
         return shouldOptimize;
       }
 
+      public boolean getKeepAlive() {
+        return keepAlive;
+      }
+
       @Override
       public boolean useNagleAlgorithm() {
         return useNagle;

src/main/java/net/spy/memcached/DefaultConnectionFactory.java

@@ -388,6 +388,15 @@ public boolean useNagleAlgorithm() {
     return false;
   }
 
+  /*
+   * (non-Javadoc)
+   *
+   * @see net.spy.memcached.ConnectionFactory#getKeepAlive()
+   */
+  public boolean getKeepAlive() {
+    return false;
+  }
+
   /*
    * (non-Javadoc)
    *

src/main/java/net/spy/memcached/MemcachedConnection.java

@@ -47,6 +47,7 @@
 import java.io.IOException;
 import java.net.ConnectException;
 import java.net.InetSocketAddress;
+import java.net.Socket;
 import java.net.SocketAddress;
 import java.net.SocketException;
 import java.nio.ByteBuffer;
@@ -349,8 +350,10 @@ protected List<MemcachedNode> createConnections(
       MemcachedNode qa = connectionFactory.createMemcachedNode(sa, ch, bufSize);
       qa.setConnection(this);
       int ops = 0;
-      ch.socket().setTcpNoDelay(!connectionFactory.useNagleAlgorithm());
-
+      Socket socket = ch.socket();
+      socket.setTcpNoDelay(!connectionFactory.useNagleAlgorithm());
+      socket.setKeepAlive(connectionFactory.getKeepAlive());
+      
       try {
         if (ch.connect(sa)) {
           getLogger().info("Connected to %s immediately", qa);

src/test/java/net/spy/memcached/ConnectionFactoryBuilderTest.java

@@ -101,6 +101,7 @@ public void testDefaults() throws Exception {
     assertFalse(f.isDaemon());
     assertFalse(f.shouldOptimize());
     assertFalse(f.useNagleAlgorithm());
+    assertFalse(f.getKeepAlive());
     assertEquals(f.getOpQueueMaxBlockTime(),
         DefaultConnectionFactory.DEFAULT_OP_QUEUE_MAX_BLOCK_TIME);
     assertEquals(f.getAuthWaitTime(),
@@ -140,6 +141,7 @@ public void connectionEstablished(SocketAddress sa, int reconnectCount) {
         .setLocatorType(Locator.CONSISTENT).setOpQueueMaxBlockTime(19)
         .setAuthDescriptor(anAuthDescriptor)
         .setAuthWaitTime(3000)
+        .setKeepAlive(true)
         .build();
 
     assertEquals(4225, f.getOperationTimeout());
@@ -156,6 +158,7 @@ public void connectionEstablished(SocketAddress sa, int reconnectCount) {
     assertTrue(f.isDaemon());
     assertFalse(f.shouldOptimize());
     assertTrue(f.useNagleAlgorithm());
+    assertTrue(f.getKeepAlive());
     assertEquals(f.getOpQueueMaxBlockTime(), 19);
     assertSame(anAuthDescriptor, f.getAuthDescriptor());
     assertEquals(f.getAuthWaitTime(), 3000);