CassandraClientMonitorMBean.java

/**
 * 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 com.datastax.drivers.jdbc.pool.cassandra.connection;

import java.util.List;
import java.util.Set;

import com.datastax.drivers.jdbc.pool.cassandra.exceptions.HectorTransportException;
import com.datastax.drivers.jdbc.pool.cassandra.service.ExhaustedPolicy;


/**
 * Defines the various JMX methods the CassandraClientMonitor exposes.
 *
 * @author Ran Tavory (ran@outbain.com)
 *
 */
public interface CassandraClientMonitorMBean {

  /**
   * @return Number of failed (and not-recovered) writes.
   */
  long getWriteFail();

  /**
   * @return Number of failed (and not recovered) reads.
   */
  long getReadFail();

  /**
   * @return Number of {@link org.apache.cassandra.thrift.TimedOutException} that the client has been able to recover from by
   * failing over to a different host in the ring.
   */
  long getRecoverableTimedOutCount();

  /**
   * @return Number of {@link org.apache.cassandra.thrift.UnavailableException} that the client has been able to recover from by
   * failing over to a different host in the ring.
   */
  long getRecoverableUnavailableCount();

  /**
   * @return Number of {@link TTransportException} that the client has been able to recover from by
   * failing over to a different host in the ring.
   */
  long getRecoverableTransportExceptionCount();

  /**
   * Returns the total number of recoverable errors which is the sum of getRecoverableTimedOutCount,
   * getRecoverableTimedOutCount and getRecoverableTransportExceptionCount
   * @return the total number of recoverable errors by failing over the other hosts.
   */
  long getRecoverableErrorCount();

  /**
   * @return Number of times a skip-host was performed. Hosts are skipped when there are errors at
   * the current host.
   */
  long getSkipHostSuccess();

  /**
   * @return Number of times clients were requested when connection pools were exhausted.
   */
  long getNumPoolExhaustedEventCount();

  /**
   * Number of existing connection pools.
   * There may be up to one pool per cassandra host.
   */
  int getNumPools();


  /**
   * Total number of idle clients in all client pools
   */
  int getNumIdleConnections();

  /**
   * Total number of active clients in all client pools
   */
  int getNumActive();

  /**
   * Number of exhausted connection pools
   * @return
   */
  int getNumExhaustedPools();

  long getRecoverableLoadBalancedConnectErrors();

  /**
   * List of exhausted pools.
   * @return
   */
  Set<String> getExhaustedPoolNames();

  /**
   * Number of threads that are currently blocked, waiting for a free connection.
   * This number may be greater than 0 only if the {@link ExhaustedPolicy} is
   * {@link ExhaustedPolicy#WHEN_EXHAUSTED_BLOCK}
   */
  int getNumBlockedThreads();

  /**
   * How many times did initial connection failed.
   * @return
   */
  long getNumConnectionErrors();

  public List<String> getKnownHosts();

  /**
   * Tells all pulls to update their list of known hosts.
   * This is useful when an admin adds/removes a host from the ring and wants the application to
   * update asap.
   */
  public void updateKnownHosts() throws HectorTransportException;

  /**
   * Retrieves stats per pool.
   *
   */
  public List<String> getStatisticsPerPool();
  
  /**
   * Add a host in the format of "[hostname]:[port]"
   * 
   * @param hostStr
   * @return
   */
  boolean addCassandraHost(String hostStr);
  
  /**
   * Remove a host in the format of "[hostname]:[port]"
   * @see {@link CassandraHost#equals(Object)} for how hosts are compared
   * 
   * @param hostStr
   * @return
   */
  boolean removeCassandraHost(String hostStr);
  
  /**
   * @see {@link #removeCassandraHost(String)} above for semantics of the host string. 
   * @see {@link HConnectionManager#removeCassandraHost(CassandraHost)} for details of this operation.
   * @param hostStr
   * @return
   */
  boolean suspendCassandraHost(String hostStr);
  
  /**
   * @see {@link #suspendCassandraHost(String)} above. This is the opposite.
   * @param hostStr
   * @return
   */
  boolean unsuspendCassandraHost(String hostStr);
  
  Set<String> getSuspendedCassandraHosts(); 
}