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 java.lang.annotation.Annotation;
013    import java.lang.reflect.AccessibleObject;
014    import java.lang.reflect.Field;
015    import java.lang.reflect.InvocationTargetException;
016    import java.security.AccessController;
017    import java.security.PrivilegedAction;
018    import java.util.ArrayList;
019    import java.util.Arrays;
020    import java.util.Collections;
021    import java.util.List;
022    
023    import org.picocontainer.ComponentMonitor;
024    import org.picocontainer.LifecycleStrategy;
025    import org.picocontainer.NameBinding;
026    import org.picocontainer.Parameter;
027    import org.picocontainer.annotations.Bind;
028    
029    /**
030     * Injection happens after instantiation, and fields are marked as 
031     * injection points via a named field.
032     */
033    @SuppressWarnings("serial")
034    public class NamedFieldInjector extends IterativeInjector {
035    
036    
037        private final List<String> fieldNames;
038    
039        public NamedFieldInjector(Object key,
040                                      Class<?> impl,
041                                      Parameter[] parameters,
042                                      ComponentMonitor componentMonitor,
043                                      LifecycleStrategy lifecycleStrategy, 
044                                      String fieldNames) {
045    
046            super(key, impl, parameters, componentMonitor, lifecycleStrategy, true);
047            this.fieldNames = Arrays.asList(fieldNames.trim().split(" "));
048        }
049    
050        protected void initializeInjectionMembersAndTypeLists() {
051            injectionMembers = new ArrayList<AccessibleObject>();
052            List<Annotation> bindingIds = new ArrayList<Annotation>();
053            final List<Class> typeList = new ArrayList<Class>();
054            final Field[] fields = getFields();
055            for (final Field field : fields) {
056                if (isNamedForInjection(field)) {
057                    injectionMembers.add(field);
058                    typeList.add(box(field.getType()));
059                    bindingIds.add(getBinding(field));
060                }
061            }
062            injectionTypes = typeList.toArray(new Class[0]);
063            bindings = bindingIds.toArray(new Annotation[0]);
064        }
065    
066        private Annotation getBinding(Field field) {
067            Annotation[] annotations = field.getAnnotations();
068            for (Annotation annotation : annotations) {
069                if (annotation.annotationType().isAnnotationPresent(Bind.class)) {
070                    return annotation;
071                }
072            }
073            return null;
074        }
075    
076        protected boolean isNamedForInjection(Field field) {
077            return fieldNames.contains(field.getName());
078        }
079    
080        private Field[] getFields() {
081            return (Field[]) AccessController.doPrivileged(new PrivilegedAction() {
082                public Object run() {
083                    return getComponentImplementation().getDeclaredFields();
084                }
085            });
086        }
087    
088    
089        protected void 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        }
095    
096        public String getDescriptor() {
097            return "NamedFieldInjector-";
098        }
099    
100        protected NameBinding makeParameterNameImpl(final AccessibleObject member) {
101            return new NameBinding() {
102                public String getName() {
103                    return ((Field) member).getName();
104                }
105            };
106        }
107    
108        List<String> getInjectionFieldNames() {
109            return Collections.unmodifiableList(fieldNames);
110        }
111    
112    
113    }