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/*
* RHQ Management Platform
* Copyright (C) 2005-2008 Red Hat, Inc.
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
package org.rhq.enterprise.agent;
/**
* Provides a count of the number of times the agent has been restarted
* and a reason for the last time the agent was restarted. More
* technically, this is the count of the number of times the
* agent was started during the full lifetime of the agent's JVM.
*
* @author John Mazzitelli
*/
public class AgentRestartCounter {
public enum AgentRestartReason {
/**
* The agent was started at agent JVM process start time.
*/
PROCESS_START,
/**
* The agent was restarted by an agent prompt command.
*/
PROMPT_COMMAND,
/**
* The agent was restarted by the agent plugin's restart operation.
*/
OPERATION,
/**
* The agent was restarted by the VM Health Check in an attempt
* to correct a critical error occurring in the agent.
*/
VM_HEALTH_CHECK,
/**
* The agent contains one or more stale resource types that need to be purged.
* This will occur when a plugin is deleted on the server and the agent is
* subsequently notified of the stale types when it sends up to the server an
* inventory report containing those types. The server will reject the report,
* throwing an exception letting the agent know it needs to restart to update
* its plugins.
*/
STALE_INVENTORY
}
private AgentRestartReason lastRestartReason = AgentRestartReason.PROCESS_START;
private int restartCount = 0;
/**
* The reason why the agent was last restarted. This is normally
* useful when you want to find out if the last time the restart occurred
* was because the VM health check thread reset the agent, but it could be
* potentially useful if you want to know that a user restarted it
* via an operation or the start prompt command.
*
* @return reason code
*/
public AgentRestartReason getLastAgentRestartReason() {
return this.lastRestartReason;
}
/**
* Returns the number of times the agent has been restarted since the
* beginning of the agent's JVM lifetime. Typically, this value will
* be 1 and the {@link #getLastAgentRestartReason() reason} will be
* {@link AgentRestartReason#PROCESS_START} to indicate the agent
* was started at JVM startup time.
* This will be 0 if the agent JVM process was created but the agent
* itself was never started at process start time.
* If this value is larger than 1, the agent was restarted for some
* reason, e.g. the VM health check thread deemed the agent at
* critically low memory and thus restarted the agent in an attempt
* to bring the agent back to normal memory usage.
*
* @return restart count
*/
public int getNumberOfRestarts() {
return this.restartCount;
}
/**
* This should be called whenever the agent is restated. This will increment
* the internal counter and set the {@link #getLastAgentRestartReason() last reason}
* to the given reason code.
*
* @param reason the reason why the agent was restarted
*/
public void restartedAgent(AgentRestartReason reason) {
this.restartCount++;
this.lastRestartReason = reason;
}
}