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* Copyright 2010, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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 javax.enterprise.context.spi;
import java.lang.annotation.Annotation;
import javax.enterprise.context.ContextNotActiveException;
/**
* Provides an operation for obtaining contextual instances with a particular scope
* of any contextual type. Any instance of {@code Context} is called a context object.
*
* The context object is responsible for creating and destroying contextual instances
* by calling operations of {@link javax.enterprise.context.spi.Contextual}. In particular,
* the context object is responsible for destroying any contextual instance it creates by
* passing the instance to
* {@link javax.enterprise.context.spi.Contextual#destroy(Object, CreationalContext)}. A
* destroyed instance must not subsequently be returned by {@code get()}.
* The context object must pass the same instance of
* {@link javax.enterprise.context.spi.CreationalContext} to {@code Contextual.destroy()}
* that it passed to {@code Contextual.create()} when it created the instance.
*
* A custom context object may be registered with the container using
* {@link javax.enterprise.inject.spi.AfterBeanDiscovery#addContext(Context)}.
*
* @author Gavin King
* @author Pete Muir
*/
public interface Context
{
/**
* Get the scope type of the context object.
*
* @return the scope
*/
public Class getScope();
/**
* Return an existing instance of certain contextual type or create a new
* instance by calling
* {@link javax.enterprise.context.spi.Contextual#create(CreationalContext)}
* and return the new instance.
*
* @param the type of contextual type
* @param contextual the contextual type
* @param creationalContext the context in which the new instance will be created
* @return the contextual instance
*
* @throws ContextNotActiveException if the context is not active
*/
public T get(Contextual contextual, CreationalContext creationalContext);
/**
* Return an existing instance of a certain contextual type or a null value.
*
* @param the type of the contextual type
* @param contextual the contextual type
* @return the contextual instance, or a null value
*
* @throws ContextNotActiveException if the context is not active
*/
public T get(Contextual contextual);
/**
* Determines if the context object is active.
*
* @return true if the context is active, or false otherwise.
*/
boolean isActive();
}