/* * Copyright 2005-2010 the original author or authors. * * 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.wamblee.inject; /** * The main entry point for programmatic dependency injection. A different * {@link InjectorFactory} can be plugged in for testing. * *
* Given the following class: *
** class Pojo { * @EJB * private Service service; * * ... * } ** * injecting the EJB into a POJO is accomplished as follows: * *
* Pojo pojo = new Pojo(); * SimpleInjector injector = new SimpleInjector(InjectorFactoryBuilder * .getInjectorFactory()); * injector.inject(pojo); ** * Of course, the above example assumes the the injector understands the * @EJB annotation (which of course CDI does). * * The
SimpleInjector
should be cached. This is because the
* SimpleInjector
caches the {@link Injector} objects that it uses
* internally for performance. This is done because creation of these internal
* Injector
objects may be costly. Caching the simple injector makes sure
* that a class is not analysed again for annotations every time injection is
* used.
*
* For more advanced cases, the injector factory can also be directly
* constructed instead of being obtained through the
* {@link InjectorFactoryBuilder}.
*
* @author Erik Brakkee
*/
public class SimpleInjector {
private InjectorCache cache;
/**
* Constructs the injector.
*
* @param aFactory
* Factory to use.
*/
public SimpleInjector(InjectorFactory aFactory) {
cache = new InjectorCache(aFactory);
}
/**
* Injects into a given object.
*
* @param aObject
* Object to inject into.
*/
public void inject(Object aObject) {
cache.getInjector(aObject.getClass()).inject(aObject);
}
}