001 /*****************************************************************************
002 * Copyright (C) PicoContainer Organization. All rights reserved. *
003 * ------------------------------------------------------------------------- *
004 * The software in this package is published under the terms of the BSD *
005 * style license a copy of which has been included with this distribution in *
006 * the LICENSE.txt file. *
007 * *
008 * Original code by *
009 *****************************************************************************/
010 package org.picocontainer.injectors;
011
012 import org.picocontainer.ComponentMonitor;
013 import org.picocontainer.NameBinding;
014 import org.picocontainer.Parameter;
015 import org.picocontainer.annotations.Bind;
016
017 import java.lang.annotation.Annotation;
018 import java.lang.reflect.AccessibleObject;
019 import java.lang.reflect.Field;
020 import java.lang.reflect.InvocationTargetException;
021 import java.lang.reflect.Type;
022 import java.security.AccessController;
023 import java.security.PrivilegedAction;
024 import java.util.ArrayList;
025 import java.util.List;
026
027 /**
028 * Injection happens after instantiation, and through fields marked as injection points via an Annotation.
029 * The default annotation of org.picocontainer.annotations.@Inject can be overridden.
030 */
031 @SuppressWarnings("serial")
032 public class AnnotatedFieldInjector extends IterativeInjector {
033
034 private final Class<? extends Annotation> injectionAnnotation;
035
036 public AnnotatedFieldInjector(Object key,
037 Class<?> impl,
038 Parameter[] parameters,
039 ComponentMonitor componentMonitor,
040 Class<? extends Annotation> injectionAnnotation, boolean useNames) {
041
042 super(key, impl, parameters, componentMonitor, useNames);
043 this.injectionAnnotation = injectionAnnotation;
044 }
045
046 @Override
047 protected void initializeInjectionMembersAndTypeLists() {
048 injectionMembers = new ArrayList<AccessibleObject>();
049 List<Annotation> bindingIds = new ArrayList<Annotation>();
050 final List<Type> typeList = new ArrayList<Type>();
051 Class drillInto = getComponentImplementation();
052 while (drillInto != Object.class) {
053 final Field[] fields = getFields(drillInto);
054 for (final Field field : fields) {
055 if (isAnnotatedForInjection(field)) {
056 injectionMembers.add(field);
057 typeList.add(box(field.getType()));
058 bindingIds.add(getBinding(field));
059 }
060 }
061 drillInto = drillInto.getSuperclass();
062 }
063 injectionTypes = typeList.toArray(new Type[0]);
064 bindings = bindingIds.toArray(new Annotation[0]);
065 }
066
067 private Annotation getBinding(Field field) {
068 Annotation[] annotations = field.getAnnotations();
069 for (Annotation annotation : annotations) {
070 if (annotation.annotationType().isAnnotationPresent(Bind.class)) {
071 return annotation;
072 }
073 }
074 return null;
075 }
076
077 protected boolean isAnnotatedForInjection(Field field) {
078 return field.getAnnotation(injectionAnnotation) != null;
079 }
080
081 private Field[] getFields(final Class clazz) {
082 return AccessController.doPrivileged(new PrivilegedAction<Field[]>() {
083 public Field[] run() {
084 return clazz.getDeclaredFields();
085 }
086 });
087 }
088
089 protected Object injectIntoMember(AccessibleObject member, Object componentInstance, Object toInject)
090 throws IllegalAccessException, InvocationTargetException {
091 Field field = (Field) member;
092 field.setAccessible(true);
093 field.set(componentInstance, toInject);
094 return null;
095 }
096
097 @Override
098 public String getDescriptor() {
099 return "AnnotatedFieldInjector-";
100 }
101
102 @Override
103 protected NameBinding makeParameterNameImpl(final AccessibleObject member) {
104 return new NameBinding() {
105 public String getName() {
106 return ((Field) member).getName();
107 }
108 };
109 }
110
111 protected Object memberInvocationReturn(Object lastReturn, AccessibleObject member, Object instance) {
112 return instance;
113 }
114 }