package org.apache.fulcrum.yaafi.framework.component;
/*
* 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.
*/
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.context.Context;
import org.apache.avalon.framework.logger.Logger;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.fulcrum.yaafi.framework.role.RoleEntry;
import org.apache.fulcrum.yaafi.framework.util.ToStringBuilder;
import org.apache.fulcrum.yaafi.framework.util.Validate;
/**
* This class implements am abstract base service component singleton with
* an arbitrary lifecycle.
*
* @author <a href="mailto:siegfried.goeschl@it20one.at">Siegfried Goeschl</a>
*/
public abstract class ServiceComponentImpl
implements ServiceComponent
{
/** the information from the role configuration file */
private RoleEntry roleEntry;
/** the actual implementation class of the service component */
private Class implementationClazz;
/** the instance of the implementation class of the service component */
private Object instance;
/** the proxy of the instance if any */
private Object proxy;
/** the Avalon logger of the container */
private Logger parentLogger;
/** the Avalon logger to be passed to the service component instance */
private Logger logger;
/** The Avalon ServiceManager passed to the service component instance */
private ServiceManager serviceManager;
/** The Avalon Context passed to the service component instance */
private Context context;
/** The Avalon Configuration passed to the service component instance */
private Configuration configuration;
/** The Avalon Parameters passed to the service component instance */
private Parameters parameters;
/**
* Constructor to parse the configuration.
*
* @param roleEntry The information extracted from the role configuration file
* @param parentLogger the logger of the service container
* @param logger The logger for the service instance
*/
public ServiceComponentImpl(
RoleEntry roleEntry, Logger parentLogger, Logger logger)
{
Validate.notNull( roleEntry, "roleEntry" );
Validate.notNull( parentLogger, "parentLogger" );
Validate.notNull( logger, "logger" );
this.roleEntry = roleEntry;
this.parentLogger = parentLogger;
this.logger = logger;
}
/////////////////////////////////////////////////////////////////////////
// Service Component Lifecycle Implementation
/////////////////////////////////////////////////////////////////////////
/**
* @see org.apache.fulcrum.yaafi.framework.component.ServiceComponentLifecycle#loadImplemtationClass(java.lang.ClassLoader)
*/
public void loadImplemtationClass(ClassLoader classLoader)
throws ClassNotFoundException
{
ClassLoader currClassLoader = null;
if( classLoader != null )
{
currClassLoader = classLoader;
}
else
{
currClassLoader = this.getClass().getClassLoader();
}
try
{
this.implementationClazz = currClassLoader.loadClass(
this.getRoleEntry().getImplementationClazzName()
);
}
catch(ClassNotFoundException e)
{
String msg = "Failed to load the implementation class "
+ this.getRoleEntry().getImplementationClazzName();
this.getParentLogger().error(msg,e);
throw e;
}
}
/**
* @see org.apache.fulcrum.yaafi.framework.component.ServiceComponentLifecycle#getInstance()
*/
public Object getInstance()
throws Exception
{
if( this.isInstantiated() == false )
{
this.createInstance();
this.incarnateInstance();
}
return this.getRawInstance(true);
}
/**
* @see org.apache.fulcrum.yaafi.framework.component.ServiceComponentLifecycle#incarnate()
*/
public void incarnate() throws Exception
{
try
{
if( this.isEarlyInit() )
{
this.getInstance();
}
}
catch(Throwable t)
{
String msg = "Failed initialize "
+ this.getRoleEntry().getImplementationClazzName();
throw new ConfigurationException(msg,t);
}
}
/**
* @see org.apache.fulcrum.yaafi.framework.component.ServiceComponentLifecycle#reconfigure()
*/
public abstract void reconfigure() throws Exception;
/**
* @see org.apache.fulcrum.yaafi.framework.component.ServiceComponentLifecycle#decommision()
*/
public void decommision() throws Exception
{
this.instance = null;
this.proxy = null;
}
/**
* @see org.apache.fulcrum.yaafi.framework.component.ServiceComponentLifecycle#dispose()
*/
public void dispose()
{
this.roleEntry = null;
this.implementationClazz = null;
this.instance = null;
this.proxy = null;
this.parentLogger = null;
this.logger = null;
this.serviceManager = null;
this.context = null;
this.configuration = null;
this.parameters = null;
}
/**
* @param logger The logger to set.
*/
public void setLogger(Logger logger)
{
this.logger = logger;
}
/**
* @param context The context to set.
*/
public void setContext(Context context)
{
this.context = context;
}
/**
* @param serviceManager The serviceManager to set.
*/
public void setServiceManager(ServiceManager serviceManager)
{
this.serviceManager = serviceManager;
}
/**
* @param configuration The configuration to set.
*/
public void setConfiguration(Configuration configuration)
{
this.configuration = configuration;
}
/**
* @param parameters The parameters to set.
*/
public void setParameters(Parameters parameters)
{
this.parameters = parameters;
}
/////////////////////////////////////////////////////////////////////////
// Generated getters and setters
/////////////////////////////////////////////////////////////////////////
/**
* @return Return true if the service is created on startup
*/
public boolean isEarlyInit()
{
return this.getRoleEntry().isEarlyInit();
}
/**
* @see org.apache.fulcrum.yaafi.framework.component.ServiceComponent#getName()
*/
public String getName()
{
return this.getRoleEntry().getName();
}
/**
* @return Returns the roleEntry.
*/
public RoleEntry getRoleEntry()
{
return roleEntry;
}
/**
* @return Returns the logger.
*/
public Logger getLogger()
{
return this.logger;
}
/**
* @return Returns the parentLogger.
*/
public Logger getParentLogger()
{
return parentLogger;
}
/**
* @return Returns the implementationClazz.
*/
public Class getImplementationClazz()
{
return this.implementationClazz;
}
/**
* @return Returns the configuration.
*/
public Configuration getConfiguration()
{
return configuration;
}
/**
* @return Returns the context.
*/
public Context getContext()
{
return context;
}
/**
* @return Returns the paramaters.
*/
public Parameters getParamaters()
{
return parameters;
}
/**
* @return Returns the serviceManager.
*/
public ServiceManager getServiceManager()
{
return serviceManager;
}
/**
* @return the shorthand of the service
*/
public String getShorthand()
{
return roleEntry.getShorthand();
}
/////////////////////////////////////////////////////////////////////////
// Class implementation
/////////////////////////////////////////////////////////////////////////
/**
* @see java.lang.Object#toString()
*/
public String toString()
{
ToStringBuilder toStringBuilder = new ToStringBuilder(this);
toStringBuilder.append("roleEntry",this.roleEntry);
toStringBuilder.append("instance",this.instance);
toStringBuilder.append("proxy",this.proxy);
return toStringBuilder.toString();
}
/**
* @return Returns <b>true</b> if the service instance was already instantiated.
*/
protected final boolean isInstantiated()
{
return ( this.instance != null ? true : false );
}
/**
* Create an instance of the service component implementation class
*
* @throws InstantiationException th
* @throws IllegalAccessException
*/
protected Object createInstance()
throws InstantiationException, IllegalAccessException
{
if( this.getParentLogger().isDebugEnabled() )
{
this.getParentLogger().debug( "Instantiating the implementation class for " + this.getShorthand() );
}
this.instance = this.implementationClazz.newInstance();
this.proxy = null;
return this.instance;
}
/**
* @see org.apache.fulcrum.yaafi.framework.component.ServiceComponent#incarnate()
*/
protected abstract void incarnateInstance() throws Exception;
/**
* Get either the original service object or the dynamic proxy
*
* @return Returns the raw instance, i.e. does not incarnate
* the instance.
*/
protected Object getRawInstance(boolean useProxy)
{
if( useProxy && (this.proxy != null) )
{
return this.proxy;
}
else
{
return this.instance;
}
}
/**
* @param proxy the service proxy instance
*/
protected void setProxyInstance(Object proxy)
{
this.proxy = proxy;
}
}