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.LifecycleStrategy;
014    import org.picocontainer.Parameter;
015    import org.picocontainer.NameBinding;
016    import org.picocontainer.annotations.Bind;
017    
018    import java.lang.annotation.Annotation;
019    import java.lang.reflect.AccessibleObject;
020    import java.lang.reflect.Field;
021    import java.lang.reflect.InvocationTargetException;
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            
035            private final Class<? extends Annotation> injectionAnnotation;
036    
037        public AnnotatedFieldInjector(Object key,
038                                      Class<?> impl,
039                                      Parameter[] parameters,
040                                      ComponentMonitor componentMonitor,
041                                      LifecycleStrategy lifecycleStrategy, 
042                                      Class<? extends Annotation> injectionAnnotation, boolean useNames) {
043    
044            super(key, impl, parameters, componentMonitor, lifecycleStrategy, useNames);
045            this.injectionAnnotation = injectionAnnotation;
046        }
047    
048        protected void initializeInjectionMembersAndTypeLists() {
049            injectionMembers = new ArrayList<AccessibleObject>();
050            List<Annotation> bindingIds = new ArrayList<Annotation>();
051            final List<Class> typeList = new ArrayList<Class>();
052            final Field[] fields = getFields();
053            for (final Field field : fields) {
054                if (isAnnotatedForInjection(field)) {
055                    injectionMembers.add(field);
056                    typeList.add(box(field.getType()));
057                    bindingIds.add(getBinding(field));
058                }
059            }
060            injectionTypes = typeList.toArray(new Class[0]);
061            bindings = bindingIds.toArray(new Annotation[0]);
062        }
063    
064        private Annotation getBinding(Field field) {
065            Annotation[] annotations = field.getAnnotations();
066            for (Annotation annotation : annotations) {
067                if (annotation.annotationType().isAnnotationPresent(Bind.class)) {
068                    return annotation;
069                }
070            }
071            return null;
072        }
073    
074        protected boolean isAnnotatedForInjection(Field field) {
075            return field.getAnnotation(injectionAnnotation) != null;
076        }
077    
078        private Field[] getFields() {
079            return (Field[]) AccessController.doPrivileged(new PrivilegedAction() {
080                public Object run() {
081                    return getComponentImplementation().getDeclaredFields();
082                }
083            });
084        }
085    
086    
087        protected void injectIntoMember(AccessibleObject member, Object componentInstance, Object toInject)
088            throws IllegalAccessException, InvocationTargetException {
089            Field field = (Field) member;
090            field.setAccessible(true);
091            field.set(componentInstance, toInject);
092        }
093    
094        public String getDescriptor() {
095            return "AnnotatedFieldInjector-";
096        }
097    
098        protected NameBinding makeParameterNameImpl(final AccessibleObject member) {
099            return new NameBinding() {
100                public String getName() {
101                    return ((Field) member).getName();
102                }
103            };
104        }
105    }