/*
* 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.
*/
package javax.enterprise.inject.spi;
import javax.enterprise.context.spi.CreationalContext;
/**
* Helper class for manually maintaining CDI created instances
* which are not managed by the CDI container.
*
* Be aware that instances created that way are <i>not</i>
* managed by the CDI container and thus need to be
* cleaned up manually to not create memory leaks!.
*
* Normal code shall use {@link javax.enterprise.inject.Instance<T>} if possible.
*
* The reason for using UnmanagedInstance is for
* @Dependent scoped instances which should not pollute the
* {@link javax.enterprise.context.spi.CreationalContext} of the containing instance.
*
* Note that the methods of UnmanagedInstance needs to be called
* in a well defined order.
*
* Please note that this classes are not thread safe!
*
* @param <T> the type of the CDI instance to create
* @since 1.1
*/
public class Unmanaged<T>
{
private BeanManager beanManager;
private InjectionTarget<T> injectionTarget;
public Unmanaged(Class<T> clazz)
{
this(CDI.current().getBeanManager(), clazz);
}
public Unmanaged(BeanManager beanManager, java.lang.Class<T> clazz)
{
this.beanManager = beanManager;
AnnotatedType<T> annotatedType = beanManager.createAnnotatedType(clazz);
injectionTarget = beanManager.createInjectionTarget(annotatedType);
}
public UnmanagedInstance<T> newInstance()
{
return new UnmanagedInstance<T>(beanManager, injectionTarget);
}
/**
* This basically delegates to the {@link javax.enterprise.inject.spi.InjectionTarget}
* interface
* @param <T> the type of the CDI instance to create
*/
public static class UnmanagedInstance<T>
{
private BeanManager beanManager;
private InjectionTarget<T> injectionTarget;
private CreationalContext<T> creationalContext;
private T instance;
private boolean injected = false;
private boolean disposed = false;
private UnmanagedInstance(BeanManager beanManager, InjectionTarget<T> injectionTarget)
{
this.injectionTarget = injectionTarget;
this.beanManager = beanManager;
}
/**
* Create the CDI instance itself. This internally just calls
* {@link javax.enterprise.inject.spi.InjectionTarget#produce(javax.enterprise.context.spi.CreationalContext)}
* and performs a few checks upfront.
*
* @throws java.lang.IllegalStateException if the instance already got created
* @throws java.lang.IllegalStateException if the instance already got disposed
*/
public UnmanagedInstance<T> produce()
{
if (creationalContext != null)
{
throw new IllegalStateException("UnmanagedInstance is already produced");
}
if (disposed)
{
throw new IllegalStateException("UnmanagedInstance is already disposed");
}
creationalContext = beanManager.createCreationalContext(null);
instance = injectionTarget.produce(creationalContext);
return this;
}
/**
* Fill @inject field, constructor and methods.
*
* @throws java.lang.IllegalStateException if the instance was not yet created
* @throws java.lang.IllegalStateException if the instance already got injected
* @throws java.lang.IllegalStateException if the instance already got disposed
* @see javax.enterprise.inject.spi.InjectionTarget#inject(Object, javax.enterprise.context.spi.CreationalContext)
*/
public UnmanagedInstance<T> inject()
{
basicCheck();
if (injected)
{
throw new IllegalStateException("UnmanagedInstance is already injected");
}
injectionTarget.inject(instance, creationalContext);
injected = true;
return this;
}
/**
* Invoke any @PostConstruct methods.
* @see javax.enterprise.inject.spi.InjectionTarget#postConstruct(Object)
*/
public UnmanagedInstance<T> postConstruct()
{
basicCheck();
injectionTarget.postConstruct(instance);
return this;
}
/**
* This method should only get called after the
* CDI instance got properly produced and initialized
* via
* {@link #produce()}
* {@link #inject()}
* {@link #postConstruct()}
*
* @return the filled cdi instance
*/
public T get()
{
basicCheck();
return instance;
}
/**
* Invoke any @PreDestroy annotated methods
* and interceptors of the given CDI instance.
*/
public UnmanagedInstance<T> preDestroy()
{
basicCheck();
injectionTarget.preDestroy(instance);
return this;
}
/**
* Dispose the CDI instance. One should call {@link #preDestroy()} before
* this method.
* @see javax.enterprise.inject.spi.InjectionTarget#dispose(Object)
*/
public UnmanagedInstance<T> dispose()
{
basicCheck();
injectionTarget.dispose(instance);
creationalContext.release();
return this;
}
/**
* Check whether the UnmanagedInstance is already initialized and not yet disposed.
*/
private void basicCheck()
{
if (creationalContext == null)
{
throw new IllegalStateException("UnmanagedInstance is not yet initialized. Invoke #produce() first!");
}
if (disposed)
{
throw new IllegalStateException("UnmanagedInstance is already disposed");
}
}
}
}