Introduce ObservableClient interface

src/main/java/com/spotify/folsom/ConnectFuture.java

@@ -29,26 +29,26 @@ public class ConnectFuture
    * @param client
    * @param awaitedState
    */
-  private ConnectFuture(RawMemcacheClient client, boolean awaitedState) {
+  private ConnectFuture(ObservableClient client, boolean awaitedState) {
     this.awaitedState = awaitedState;
     client.registerForConnectionChanges(this);
     check(client);
   }
 
-  public static ListenableFuture<Void> disconnectFuture(RawMemcacheClient client) {
+  public static ListenableFuture<Void> disconnectFuture(ObservableClient client) {
     return new ConnectFuture(client, false);
   }
 
-  public static ListenableFuture<Void> connectFuture(RawMemcacheClient client) {
+  public static ListenableFuture<Void> connectFuture(ObservableClient client) {
     return new ConnectFuture(client, true);
   }
 
   @Override
-  public void connectionChanged(RawMemcacheClient client) {
+  public void connectionChanged(ObservableClient client) {
     check(client);
   }
 
-  private void check(RawMemcacheClient client) {
+  private void check(ObservableClient client) {
     if (awaitedState == client.isConnected()) {
       if (set(null)) {
         client.unregisterForConnectionChanges(this);

src/main/java/com/spotify/folsom/ConnectionChangeListener.java

@@ -20,5 +20,5 @@
 public interface ConnectionChangeListener {
 
   @Subscribe
-  void connectionChanged(RawMemcacheClient client);
+  void connectionChanged(ObservableClient client);
 }

src/main/java/com/spotify/folsom/ObservableClient.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2015 Spotify AB
+ *
+ * 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 com.spotify.folsom;
+
+/**
+ * Implementations of this interface has a notion of connectedness to a remote
+ * and the ability to notify listeners of connection state changes.
+ */
+public interface ObservableClient {
+  /**
+   * Register for connection change events. This should trigger at least once for every
+   * connection change. You should immediately get an initial callback.
+   * @param listener the listener to notify of connection changes
+   */
+  void registerForConnectionChanges(ConnectionChangeListener listener);
+
+  /**
+   * Unregister for connection change events.
+   * @param listener the listener that should no longer receive connection change
+   *                 notifications
+   */
+  void unregisterForConnectionChanges(ConnectionChangeListener listener);
+
+
+  /**
+   * Is the client connected to a server?
+   * @return true if the client is connected
+   */
+  boolean isConnected();
+}

src/main/java/com/spotify/folsom/RawMemcacheClient.java

@@ -22,7 +22,7 @@
 /**
  * A raw memcache client, mostly useful internally
  */
-public interface RawMemcacheClient {
+public interface RawMemcacheClient extends ObservableClient {
 
   <T> ListenableFuture<T> send(Request<T> request);
 
@@ -32,12 +32,6 @@ public interface RawMemcacheClient {
    */
   void shutdown();
 
-  /**
-   * Is the client connected to a server?
-   * @return true if the client is connected
-   */
-  boolean isConnected();
-
   /**
    * How many actual socket connections do we have, including currently disconnected clients.
    * @return the number of total connections
@@ -49,17 +43,4 @@ public interface RawMemcacheClient {
    * @return the number of active connections
    */
   int numActiveConnections();
-
-  /**
-   * Register for connection change events. This should trigger at least once for every
-   * connection change. You should immediately get an initial callback.
-   * @param listener
-   */
-  void registerForConnectionChanges(ConnectionChangeListener listener);
-
-  /**
-   * Unregister for connection change events.
-   * @param listener
-   */
-  void unregisterForConnectionChanges(ConnectionChangeListener listener);
 }

src/main/java/com/spotify/folsom/SrvKetamaClient.java

@@ -212,7 +212,7 @@ public void run() {
 
   private class MyConnectionChangeListener implements ConnectionChangeListener {
     @Override
-    public void connectionChanged(RawMemcacheClient client) {
+    public void connectionChanged(ObservableClient client) {
       notifyConnectionChange();
     }
   }

src/main/java/com/spotify/folsom/client/AbstractMultiMemcacheClient.java

@@ -19,6 +19,7 @@
 import com.google.common.base.Preconditions;
 import com.spotify.folsom.AbstractRawMemcacheClient;
 import com.spotify.folsom.ConnectionChangeListener;
+import com.spotify.folsom.ObservableClient;
 import com.spotify.folsom.RawMemcacheClient;
 
 import java.util.Collection;
@@ -79,7 +80,7 @@ public String toString() {
   }
 
   @Override
-  public void connectionChanged(RawMemcacheClient client) {
+  public void connectionChanged(ObservableClient client) {
     notifyConnectionChange();
   }
 }