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 *****************************************************************************/
010package org.picocontainer.injectors;
011
012import org.picocontainer.ComponentMonitor;
013import org.picocontainer.NameBinding;
014import org.picocontainer.Parameter;
015import org.picocontainer.PicoContainer;
016import org.picocontainer.annotations.Bind;
017
018import java.lang.annotation.Annotation;
019import java.lang.reflect.AccessibleObject;
020import java.lang.reflect.Field;
021import java.lang.reflect.InvocationTargetException;
022import java.lang.reflect.Type;
023import java.security.AccessController;
024import java.security.PrivilegedAction;
025import java.util.ArrayList;
026import java.util.List;
027import java.util.Set;
028
029/**
030 * Injection happens after instantiation, and through fields marked as injection points via an Annotation.
031 * The default annotation of org.picocontainer.annotations.@Inject can be overridden.
032 */
033@SuppressWarnings("serial")
034public class AnnotatedFieldInjector<T> extends AbstractFieldInjector<T> {
035
036    private final Class<? extends Annotation> injectionAnnotation;
037
038    public AnnotatedFieldInjector(Object key,
039                                  Class<?> impl,
040                                  Parameter[] parameters,
041                                  ComponentMonitor componentMonitor,
042                                  Class<? extends Annotation> injectionAnnotation, boolean useNames) {
043
044        super(key, impl, parameters, componentMonitor, useNames);
045        this.injectionAnnotation = injectionAnnotation;
046    }
047
048    @Override    
049    protected void initializeInjectionMembersAndTypeLists() {
050        injectionMembers = new ArrayList<AccessibleObject>();
051        List<Annotation> bindingIds = new ArrayList<Annotation>();
052        final List<Type> typeList = new ArrayList<Type>();
053        Class drillInto = getComponentImplementation();
054        while (drillInto != Object.class) {
055            final Field[] fields = getFields(drillInto);
056            for (final Field field : fields) {
057                if (isAnnotatedForInjection(field)) {
058                    injectionMembers.add(field);
059                    typeList.add(box(field.getType()));
060                    bindingIds.add(getBinding(field));
061                }
062            }
063            drillInto = drillInto.getSuperclass();
064        }
065        injectionTypes = typeList.toArray(new Type[0]);
066        bindings = bindingIds.toArray(new Annotation[0]);
067    }
068
069    private Annotation getBinding(Field field) {
070        Annotation[] annotations = field.getAnnotations();
071        for (Annotation annotation : annotations) {
072            if (annotation.annotationType().isAnnotationPresent(Bind.class)) {
073                return annotation;
074            }
075        }
076        return null;
077    }
078
079    protected boolean isAnnotatedForInjection(Field field) {
080        return field.getAnnotation(injectionAnnotation) != null;
081    }
082
083    private Field[] getFields(final Class clazz) {
084        return AccessController.doPrivileged(new PrivilegedAction<Field[]>() {
085            public Field[] run() {
086                return clazz.getDeclaredFields();
087            }
088        });
089    }
090
091    protected Object injectIntoMember(AccessibleObject member, Object componentInstance, Object toInject)
092            throws IllegalAccessException, InvocationTargetException {
093        Field field = (Field) member;
094        field.setAccessible(true);
095        field.set(componentInstance, toInject);
096        return null;
097    }
098
099    @Override
100    public String getDescriptor() {
101        return "AnnotatedFieldInjector-";
102    }
103
104    @Override
105    protected NameBinding makeParameterNameImpl(final AccessibleObject member) {
106        return new NameBinding() {
107            public String getName() {
108                return ((Field) member).getName();
109            }
110        };
111    }
112
113    protected Object memberInvocationReturn(Object lastReturn, AccessibleObject member, Object instance) {
114        return instance;
115    }
116}