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/*
* Copyright 1997-2011 teatrove.org
*
* 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.
*/
package org.teatrove.tea.engine;
/**
* Instances of this kind of ContextSource can support reloading their context
* class. {@link TeaExecutionEngine Engines} that support context reload will
* discover that the context class has changed by calling getContextType. This
* call will likely be initiated by a template reload request, since all
* templates may need to be recompiled if the context class has changed.
*
* Because Tea engines may execute many templates concurrently, the two
* argument createContext method is called to inform the context source
* what specific context class is tied to the application request. The returned
* context instance must be of the requested type. DynamicContextSources must
* support instantiating the old context class(es) as well as the new context
* class.
*
* The context source may release old context classes to free resources only
* when it is safe to do so. One way of achieving this is by using weak
* references.
*
* @author Jonathan Colwell
*/
public interface DynamicContextSource extends ContextSource {
/**
* Creates a context instance that must be of the requested type.
*
* @param contextClass Expected type of returned context instance
* @param param {@link TeaExecutionEngine engine} specific parameter that
* may be used to create the context instance
*/
public Object createContext(Class contextClass, Object param)
throws Exception;
}