/*
 * JBoss, Home of Professional Open Source
 * Copyright 2008, Red Hat Middleware LLC, 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.spi;

import java.lang.annotation.Annotation;
import java.lang.reflect.Member;
import java.lang.reflect.Type;
import java.util.Set;


/**
 * <p>Provides access to metadata about an injection point. May represent an 
 * {@linkplain javax.inject.Inject injected field} or a parameter of a 
 * {@linkplain javax.inject.Inject bean constructor}, 
 * {@linkplain javax.inject.Inject initializer method}, 
 * {@linkplain javax.enterprise.inject.Produces producer method}, 
 * {@linkplain javax.enterprise.inject.Disposes disposer method} or 
 * {@linkplain javax.enterprise.event.Observes observer method}.</p>
 * 
 * <p>Occasionally, a bean with scope 
 * {@link javax.enterprise.context.Dependent &#064;Dependent} needs to access 
 * metadata relating to the object to which it belongs. The bean may inject an 
 * {@code InjectionPoint} representing the injection point into which the bean 
 * was injected.</p>
 * 
 * <p>For example, the following producer method creates injectable <tt>Logger</tt>s. 
 * The log category of a <tt>Logger</tt> depends upon the class of the object into 
 * which it is injected.</p>
 * 
 * <pre>
 * &#064;Produces 
 * Logger createLogger(InjectionPoint injectionPoint) { 
 *    return Logger.getLogger( injectionPoint.getMember().getDeclaringClass().getName() );
 * }
 * </pre>
 * 
 * <p>Only {@linkplain javax.enterprise.context.Dependent dependent} objects, may 
 * obtain information about the injection point to which they belong.</p>
 * 
 * @author Gavin King
 * @author Pete Muir
 */
public interface InjectionPoint
{
   
   /**
    * Get the required type of injection point.
    * 
    * @return the required type
    */
   public Type getType();
   
   /**
    * Get the required qualifiers of the injection point.
    * 
    * @return the required qualifiers
    */
   public Set<Annotation> getQualifiers();
   
   /**
    * Get the {@link javax.enterprise.inject.spi.Bean} object representing the 
    * bean that defines the injection point. If the injection point does not 
    * belong to a bean, return a null value.
    * 
    * @return the {@link javax.enterprise.inject.spi.Bean} object representing 
    *         bean that defines the injection point, of null if the injection 
    *         point does not belong to a bean
    */
   public Bean<?> getBean();
   
   /**
    * Get the {@link java.lang.reflect.Field} object in the case of field 
    * injection, the {@link java.lang.reflect.Method} object in
    * the case of method parameter injection or the 
    * {@link java.lang.reflect.Constructor} object in the case of constructor 
    * parameter injection.
    * 
    * @return the member
    */
   public Member getMember();
   
   /**
    * Obtain an instance of {@link javax.enterprise.inject.spi.AnnotatedField} 
    * or {@link javax.enterprise.inject.spi.AnnotatedParameter}, depending upon 
    * whether the injection point is an injected field or a constructor/method parameter.
    * 
    * @return an {@code AnnotatedField} or {@code AnnotatedParameter}
    */
   public Annotated getAnnotated();
   
   /**
    * Determines if the injection point is a decorator delegate injection point.
    * 
    * @return <tt>true</tt> if the injection point is a decorator delegate injection point, 
    * and <tt>false</tt> otherwise
    */
   public boolean isDelegate();
   
   /**
    * Determines if the injection is a transient field.
    * 
    * @return <tt>true</tt> if the injection point is a transient field, and <tt>false</tt> 
    * otherwise
    */
   public boolean isTransient();
}
