Produces.java

/*
 * JBoss, Home of Professional Open Source
 * 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.inject;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

/**
 * 
 * <p>
 * Identifies a producer method or field. May be applied to a method or field of a bean class.
 * </p>
 * 
 * <p>
 * A producer method must be a non-abstract method of a managed bean class or session bean class. A producer method may be
 * either static or non-static. If the bean is a session bean, the producer method must be either a business method of the EJB
 * or a static method of the bean class.
 * </p>
 * 
 * <pre>
 * public class Shop {
 *    @Produces @ApplicationScoped 
 *    @Catalog @Named("catalog") 
 *    List<Product> getProducts() { ... }
 *    ...
 * }
 * </pre>
 * 
 * <p>
 * A producer field must be a field of a managed bean class or session bean class. A producer field may be either static or
 * non-static. If the bean is a session bean, the producer field must be a static field of the bean class.
 * </p>
 * 
 * <pre>
 * public class Shop { 
 *    @Produces @ApplicationScoped 
 *    @Catalog @Named("catalog") 
 *    List<Product> products = ...;
 *    ...
 * }
 * </pre>
 * 
 * <p>
 * If a producer method sometimes returns a null value, or if a producer field sometimes contains a null value when accessed,
 * then the producer method or field must have scope {@link javax.enterprise.context.Dependent @Dependent}.
 * </p>
 * 
 * <p>
 * A producer method return type or producer field type may not be a type variable.
 * </p>
 * 
 * <p>
 * If the producer method return type or producer field type is a parameterized type, it must specify an actual type parameter
 * or type variable for each type parameter.
 * </p>
 * 
 * <p>
 * If the producer method return type or producer field type is a parameterized type with a type variable, it must have scope
 * {@link javax.enterprise.context.Dependent @Dependent}.
 * </p>
 * 
 * <p>
 * A producer method may have any number of parameters. All producer method parameters are injection points.
 * </p>
 * 
 * <pre>
 * public class OrderFactory {
 * 
 *     @Produces
 *     @ConversationScoped
 *     public Order createCurrentOrder(Shop shop, @Selected Product product) {
 *         Order order = new Order(product, shop);
 *         return order;
 *     }
 * 
 * }
 * </pre>
 * 
 * <p>
 * A bean may declare multiple producer methods or fields.
 * </p>
 * 
 * <p>
 * Producer methods and fields are not inherited by bean subclasses.
 * </p>
 * 
 * <p>
 * Interceptors and decorators may not declare producer methods or fields.
 * </p>
 * 
 * @see javax.enterprise.inject.Disposes @Disposes
 * 
 * @author Gavin King
 * @author Pete Muir
 */

@Target({ METHOD, FIELD })
@Retention(RUNTIME)
@Documented
public @interface Produces {
}