Adding the FailureDetector MBean support

This adds the FailureDetectorMBean and its implementation.
Setting the phi is not supported yet and will be added when the code
will be completed inside the failure_detector implementation.

Signed-off-by: Amnon Heiman <amnon@cloudius-systems.com>

src/main/java/org/apache/cassandra/gms/FailureDetector.java

@@ -0,0 +1,100 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+/*
+ * Copyright 2015 Cloudius Systems
+ *
+ * Modified by Cloudius Systems
+ */
+
+package org.apache.cassandra.gms;
+
+import java.lang.management.ManagementFactory;
+import java.net.UnknownHostException;
+import java.util.*;
+import javax.management.MBeanServer;
+import javax.management.ObjectName;
+
+import com.cloudius.urchin.api.APIClient;
+
+public class FailureDetector implements FailureDetectorMBean {
+    public static final String MBEAN_NAME = "org.apache.cassandra.net:type=FailureDetector";
+    private static final java.util.logging.Logger logger = java.util.logging.Logger
+            .getLogger(FailureDetector.class.getName());
+
+    private APIClient c = new APIClient();
+
+    public void log(String str) {
+        logger.info(str);
+    }
+
+    private static final FailureDetector instance = new FailureDetector();
+
+    public static FailureDetector getInstance() {
+        return instance;
+    }
+
+    private FailureDetector() {
+        // Register this instance with JMX
+        try {
+            MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
+            mbs.registerMBean(this, new ObjectName(MBEAN_NAME));
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public void dumpInterArrivalTimes() {
+        log(" dumpInterArrivalTimes()");
+    }
+
+    public void setPhiConvictThreshold(double phi) {
+        log(" setPhiConvictThreshold(double phi)");        
+    }
+
+    public double getPhiConvictThreshold() {
+        log(" getPhiConvictThreshold()");
+        return c.getDoubleValue("/failure_detector/phi");
+    }
+
+    public String getAllEndpointStates() {
+        log(" getAllEndpointStates()");
+        return c.getStringValue("/failure_detector/endpoints");
+    }
+
+    public String getEndpointState(String address) throws UnknownHostException {
+        log(" getEndpointState(String address) throws UnknownHostException");
+        return c.getStringValue("/failure_detector/endpoints/states/" +  address);
+    }
+
+    public Map<String, String> getSimpleStates() {
+        log(" getSimpleStates()");
+        return c.getMapStrValue("/failure_detector/simple_states");
+    }
+
+    public int getDownEndpointCount() {
+        log(" getDownEndpointCount()");
+        return c.getIntValue("/failure_detector/count/endpoint/down");
+    }
+
+    public int getUpEndpointCount() {
+        log(" getUpEndpointCount()");
+        return c.getIntValue("/failure_detector/count/endpoint/up");
+    }
+
+}

src/main/java/org/apache/cassandra/gms/FailureDetectorMBean.java

@@ -0,0 +1,40 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.cassandra.gms;
+
+import java.net.UnknownHostException;
+import java.util.Map;
+
+public interface FailureDetectorMBean
+{
+    public void dumpInterArrivalTimes();
+
+    public void setPhiConvictThreshold(double phi);
+
+    public double getPhiConvictThreshold();
+
+    public String getAllEndpointStates();
+
+    public String getEndpointState(String address) throws UnknownHostException;
+
+    public Map<String, String> getSimpleStates();
+
+    public int getDownEndpointCount();
+
+    public int getUpEndpointCount();
+}