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package com.sun.enterprise.admin.monitor.registry.spi.reconfig;

import java.util.Iterator;
import java.util.Map;
import java.util.logging.Logger;
import com.sun.enterprise.admin.monitor.registry.MonitoringLevel;
import com.sun.enterprise.admin.monitor.registry.MonitoredObjectType;
import com.sun.enterprise.admin.monitor.registry.StatsHolder;
import com.sun.enterprise.admin.monitor.registry.MonitoringLevelListener;

import com.sun.enterprise.admin.monitor.registry.spi.ValueListMap;
import com.sun.enterprise.admin.monitor.registry.spi.MonitoringRegistrationHelper;
import com.sun.enterprise.admin.common.constant.AdminConstants;

/**
 * Provides for dynamic reconfiguration of jvm. This class decides the 
 * actions to take when there are changes to the monitoring level through 
 * administrative interfaces.
 * @since S1AS8.1
 */
class JVMChangeHandler implements ChangeHandler {
	
	private final ChangeHandler		successor;
	private final ValueListMap		listeners;
	private static final Logger logger = Logger.getLogger(AdminConstants.kLoggerName);

	JVMChangeHandler(ChangeHandler successor, ValueListMap listeners) {
		this.successor	= successor;
		this.listeners	= listeners;
	}
	
	public void handleChange(MonitoredObjectType t, MonitoringLevel from, MonitoringLevel to) {
		if (isJvmType(t)) {
			handleChange(from, to, t);
		}
		else {
			successor.handleChange(t, from, to);
		}
	}
	
    private boolean isJvmType(MonitoredObjectType t) {
        return (t == MonitoredObjectType.JVM);
    }
	
	private void handleChange(MonitoringLevel from, MonitoringLevel to, MonitoredObjectType t) {
		if (off2Low(from, to) || off2High(from, to)) {
			boolean threadInfo = false;
			notifyListeners(from, to, t);
			// register the threadinfo mbeans only if the "to" level is HIGH
			if(to == MonitoringLevel.HIGH)
				threadInfo = true;
			registerMBeans(threadInfo);
		}
		if (low2Off(from, to) || high2Off(from, to)) {
			boolean threadInfo = false;
			// need to include the threadinfo mbeans, if the "from" level is HIGH
			if(from == MonitoringLevel.HIGH)
				threadInfo = true;
			unregisterMBeans(threadInfo);
			notifyListeners(from, to, t);
		}
		if (low2High(from, to)) {
			// register the threadinfo mbeans
			notifyListeners(from, to, t);
			registerThreadInfoMBeans();
		}
		if (high2Low(from, to)) {
			// unregister the threadinfo mbeans
			unregisterThreadInfoMBeans();
			notifyListeners(from, to, t);
		}
		
	}
	
	private void notifyListeners(MonitoringLevel from, MonitoringLevel to, MonitoredObjectType t) {
		logger.finer("DynamicReconfigurator: Now notifying the listeners for jvm stats --- from = " + from.toString() + " to = " + to.toString());
		final Map l = (Map)listeners.get(t); // map of listeners;
		if (l == null)
			return; //do nothing
		final Iterator it = l.keySet().iterator();
		while (it.hasNext()) {
			final MonitoringLevelListener ml = (MonitoringLevelListener)it.next();
			ml.changeLevel(from, to, t);
		}
	}
	
	
	private void registerMBeans(boolean threadInfo) {
		final MonitoringRegistrationHelper registryImpl	= 
			(MonitoringRegistrationHelper) MonitoringRegistrationHelper.getInstance();
		
		final Iterator iter = registryImpl.getJvmNodes(threadInfo).iterator();
		while (iter.hasNext()) {
			final StatsHolder c = (StatsHolder) iter.next();
			c.registerMBean();
			logger.finer("DynamicReconfigurator: Now Registering MBean for --- " + c.getName());
		}
	}
	
	private void unregisterMBeans(boolean threadInfo) {
		final MonitoringRegistrationHelper registryImpl	= 
			(MonitoringRegistrationHelper) MonitoringRegistrationHelper.getInstance();

		final Iterator iter = registryImpl.getJvmNodes(threadInfo).iterator();
		while (iter.hasNext()) {
			final StatsHolder c = (StatsHolder) iter.next();
			c.unregisterMBean();
			logger.finer("DynamicReconfigurator: Now UnRegistering MBean for --- " + c.getName());
		}
	}
	
	
	private void registerThreadInfoMBeans() {
		final MonitoringRegistrationHelper registryImpl	= 
			(MonitoringRegistrationHelper) MonitoringRegistrationHelper.getInstance();

		final Iterator iter = registryImpl.getJvmThreadInfoNodes().iterator();
		while (iter.hasNext()) {
			final StatsHolder c = (StatsHolder) iter.next();
			c.registerMBean();
			logger.finer("DynamicReconfigurator: Now Registering MBean for --- " + c.getName());
		}
	}
	

	private void unregisterThreadInfoMBeans() {
		final MonitoringRegistrationHelper registryImpl	= 
			(MonitoringRegistrationHelper) MonitoringRegistrationHelper.getInstance();

		final Iterator iter = registryImpl.getJvmThreadInfoNodes().iterator();
		while (iter.hasNext()) {
			final StatsHolder c = (StatsHolder) iter.next();
			c.unregisterMBean();
			logger.finer("DynamicReconfigurator: Now UnRegistering MBean for --- " + c.getName());
		}
	}
	
	private boolean off2Low(MonitoringLevel from, MonitoringLevel to) { 
		return ( from == MonitoringLevel.OFF && to == MonitoringLevel.LOW );
	}
	private boolean off2High(MonitoringLevel from, MonitoringLevel to) { 
		return ( from == MonitoringLevel.OFF && to == MonitoringLevel.HIGH );
	}
	private boolean low2Off(MonitoringLevel from, MonitoringLevel to) { 
		return ( from == MonitoringLevel.LOW && to == MonitoringLevel.OFF);
	}
	private boolean high2Off(MonitoringLevel from, MonitoringLevel to) { 
		return ( from == MonitoringLevel.HIGH && to == MonitoringLevel.OFF );
	}
	private boolean low2High(MonitoringLevel from, MonitoringLevel to) { 
		return ( from == MonitoringLevel.LOW && to == MonitoringLevel.HIGH);
	}
	private boolean high2Low(MonitoringLevel from, MonitoringLevel to) {
		return ( from == MonitoringLevel.HIGH && to == MonitoringLevel.LOW );
	}
}