/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.ha.singleton;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.security.InvalidParameterException;
import javax.management.InstanceNotFoundException;
import javax.management.MBeanException;
import javax.management.ObjectName;
import javax.management.ReflectionException;
/**
* A clustered singleton service that calls a configurable
* method on a target (m)bean, whenever the current node becomes
* the master. Correspondingly, it calls a configurable method
* on the target (m)bean, whenever the current node resigns from
* being the master.
*
* Optional string arguments may be passed to those methods.
*
* @author <a href="mailto:ivelin@apache.org">Ivelin Ivanov</a>
* @author <a href="mailto:scott.stark@jboss.org">Scott Stark</a>
* @author <a href="mailto:mr@gedoplan.de">Marcus Redeker</a>
* @author <a href="mailto:dimitris@jboss.org">Dimitris Andreadis</a>
* @author Brian Stansberry
*
* @version $Revision: 81001 $
*/
public class HASingletonController extends HASingletonSupport
implements HASingletonControllerMBean
{
// Private Data --------------------------------------------------
private ObjectName mSingletonMBean;
private Object mSingleton;
private String mSingletonStartMethod = "startSingleton";
private String mSingletonStopMethod = "stopSingleton";
private String mSingletonStartMethodArgument;
private String mSingletonStopMethodArgument;
private static final Object[] NO_ARGS = new Object[0];
private static final String[] NO_TYPE_NAMES = new String[0];
private static final Class<?>[] NO_TYPES = new Class[0];
// Attributes ----------------------------------------------------
public Object getTarget()
{
return this.mSingleton;
}
public void setTarget(Object target)
{
this.mSingleton = target;
}
public ObjectName getTargetName()
{
return this.mSingletonMBean;
}
public void setTargetName(ObjectName targetObjectName)
{
this.mSingletonMBean = targetObjectName;
}
public String getTargetStartMethod()
{
return this.mSingletonStartMethod;
}
public void setTargetStartMethod(String targetStartMethod)
throws InvalidParameterException
{
if (targetStartMethod != null)
{
this.mSingletonStartMethod = targetStartMethod;
}
}
public String getTargetStopMethod()
{
return this.mSingletonStopMethod;
}
public void setTargetStopMethod(String targetStopMethod)
throws InvalidParameterException
{
if (targetStopMethod != null)
{
this.mSingletonStopMethod = targetStopMethod;
}
}
public String getTargetStartMethodArgument()
{
return this.mSingletonStartMethodArgument ;
}
public void setTargetStartMethodArgument(String targetStartMethodArgument)
{
this.mSingletonStartMethodArgument = targetStartMethodArgument;
}
public String getTargetStopMethodArgument()
{
return this.mSingletonStopMethodArgument ;
}
public void setTargetStopMethodArgument(String targetStopMethodArgument)
{
this.mSingletonStopMethodArgument = targetStopMethodArgument;
}
// HASingleton implementation ------------------------------------
/**
* Call the target start method
*
* @see org.jboss.ha.singleton.HASingletonSupport#startSingleton()
*/
@Override
public void startSingleton()
{
super.startSingleton();
try
{
if (this.mSingleton != null)
{
this.invokeSingletonMethod( this.mSingleton, this.mSingletonStartMethod, this.mSingletonStartMethodArgument);
}
else if (this.mSingletonMBean != null)
{
this.invokeSingletonMBeanMethod( this.mSingletonMBean, this.mSingletonStartMethod, this.mSingletonStartMethodArgument);
}
else
{
this.log.warn("No singleton configured; cannot start");
}
}
catch (Exception e)
{
this.log.error("Controlled Singleton failed to become master", e);
}
}
/**
* Call the target stop method
*
* @see org.jboss.ha.singleton.HASingletonSupport#stopSingleton()
*/
@Override
public void stopSingleton()
{
super.stopSingleton();
try
{
if (this.mSingleton != null)
{
this.invokeSingletonMethod( this.mSingleton, this.mSingletonStopMethod, this.mSingletonStopMethodArgument);
}
else if (this.mSingletonMBean != null)
{
this.invokeSingletonMBeanMethod( this.mSingletonMBean, this.mSingletonStopMethod, this.mSingletonStopMethodArgument);
}
else
{
this.log.warn("No singleton configured; cannot start");
}
}
catch (Exception e)
{
this.log.error("Controlled Singleton failed to resign from master position", e);
}
}
// Protected -----------------------------------------------------
protected Object invokeSingletonMethod(Object target,
String operationName, Object param)
throws IllegalAccessException, InvocationTargetException, NoSuchMethodException
{
if (target != null && operationName != null)
{
Object[] params;
Class<?>[] types;
if (param != null)
{
params = new Object[] { param };
types = new Class[] { param.getClass() };
this.log.debug("Calling operation: " + operationName + "(" + param + "), on target: '" + target + "'");
}
else
{
params = NO_ARGS;
types = NO_TYPES;
this.log.debug("Calling operation: " + operationName + "(), on target: '" + target + "'");
}
Method method = getTargetMethod(target, operationName, types);
return method.invoke(target, params);
}
this.log.debug("No configured target mbean or operation to call");
return null;
}
protected Object invokeSingletonMBeanMethod(ObjectName target,
String operationName, Object param)
throws InstanceNotFoundException, MBeanException, ReflectionException
{
if (target != null && operationName != null)
{
Object[] params;
String[] signature;
if (param != null)
{
params = new Object[] { param };
signature = new String[] { param.getClass().getName() };
this.log.debug("Calling operation: " + operationName +
"(" + param + "), on target: '" + target + "'");
}
else
{
params = NO_ARGS;
signature = NO_TYPE_NAMES;
this.log.debug("Calling operation: " + operationName +
"(), on target: '" + target + "'");
}
return this.server.invoke(target, operationName, params, signature);
}
this.log.debug("No configured target mbean or operation to call");
return null;
}
public static Method getTargetMethod(Object target, String methodName, Class<?>[] types)
throws NoSuchMethodException
{
Class<?> clazz = target.getClass();
NoSuchMethodException nsme = null;
while (clazz != null)
{
try
{
Method method = clazz.getDeclaredMethod(methodName, types);
return method;
}
catch (NoSuchMethodException e)
{
// Cache the one from the top level class
if (nsme == null)
{
nsme = e;
}
// Keep searching
clazz = clazz.getSuperclass();
}
}
throw nsme;
}
}