package org.apache.beehive.controls.api.bean;
/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed 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.
*
* $Header:$
*/
import org.apache.beehive.controls.api.properties.PropertyMap;
import org.apache.beehive.controls.api.bean.ControlBean;
import org.apache.beehive.controls.api.context.ControlBeanContext;
import org.apache.beehive.controls.api.ControlException;
import org.apache.beehive.controls.spi.bean.ControlFactory;
import org.apache.beehive.controls.spi.bean.JavaControlFactory;
import org.apache.commons.discovery.tools.DiscoverClass;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
/**
* Helper class for using controls. Includes static methods to help instantiate controls, and initialize
* declarative control clients.
*/
public class Controls
{
final private static String DEFAULT_FACTORY_CLASS = JavaControlFactory.class.getName();
/**
* Factory method for instantiating controls. Controls instantiated using this method will be associated with the
* current thread-local ControlBeanContext (possibly none), and have an auto-generated ID.
*
* @param cl the classloader used to load the ControlBean. If null, the system classloader will be used.
* @param beanName the fully qualified name of the ControlBean class.
* @param props an optional PropertyMap containing initial property values for the control. May be null.
* @return an instance of the specified ControlBean.
* @throws ClassNotFoundException
*/
public static ControlBean instantiate( ClassLoader cl,
String beanName,
PropertyMap props )
throws ClassNotFoundException
{
return instantiate( cl, beanName, props, null, null );
}
/**
* Factory method for instantiating controls.
*
* @param cl the classloader used to load the ControlBean. If null, the system classloader will be used.
* @param beanName the fully qualified name of the ControlBean class.
* @param props an optional PropertyMap containing initial property values for the control. May be null.
* @param cbc the ControlBeanContext that will nest the created control. If null, the thread-local context
* (possibly none) will be used.
* @param id a unique ID for the created control. If null, an ID will be auto-generated.
* @return an instance of the specified ControlBean.
* @throws ClassNotFoundException
*/
public static ControlBean instantiate( ClassLoader cl,
String beanName,
PropertyMap props,
ControlBeanContext cbc,
String id )
throws ClassNotFoundException
{
Class beanClass = ( cl == null ) ? Class.forName( beanName ) : cl.loadClass( beanName );
return instantiate(beanClass, props, cbc, id);
}
/**
* Factory method for instantiating controls.
*
* @param beanClass the ControlBean class to instantiate
* @param props an optional PropertyMap containing initial property values for the control.
* may be null.
* @param context the ControlBeanContext that will nest the created control. If null, the
* thread-local context (possibly none) will be used.
* @param id a unique ID for the created control. If null, an ID will be auto-generated.
* @return an instance of the specified ControlBean.
*/
public static <T extends ControlBean> T instantiate( Class<T> beanClass,
PropertyMap props,
ControlBeanContext context,
String id )
{
try
{
DiscoverClass discoverer = new DiscoverClass();
Class factoryClass = discoverer.find( ControlFactory.class, DEFAULT_FACTORY_CLASS );
ControlFactory factory = (ControlFactory)factoryClass.newInstance();
return factory.instantiate( beanClass, props, context, id );
}
catch ( Exception e )
{
throw new ControlException( "Exception creating ControlBean", e );
}
}
/**
* Helper method for initializing instances of declarative control clients (objects that use controls via @Control
* and @EventHandler annotations). This method runs the client-specific generated ClientInitializer class to do
* its initialization work.
*
* @param cl the classloader used to load the ClientInitializer. If null, defaults to the classloader used to
* load the client object being initialized.
* @param client the client object being initialized.
* @param cbc the ControlBeanContext to be associated with the client object (that will nest the controls the client
* defines). If null, the thread-local context (possibly none) will be used.
* @throws ControlException
* @throws ClassNotFoundException
*/
public static void initializeClient( ClassLoader cl, Object client, ControlBeanContext cbc )
throws ClassNotFoundException
{
Class clientClass = client.getClass();
String clientName = clientClass.getName();
if ( cl == null )
cl = clientClass.getClassLoader();
String initName = clientName + "ClientInitializer";
Class initClass = cl.loadClass( initName );
try
{
Method m = initClass.getMethod( "initialize", ControlBeanContext.class, clientClass );
m.invoke(null, cbc, client );
}
catch ( Throwable e )
{
if ( e instanceof InvocationTargetException )
{
if ( e.getCause() != null )
{
e = e.getCause();
}
}
throw new ControlException( "Exception trying to run client initializer: " + e.getClass().getName() + ", " +
e.getMessage(), e );
}
}
}