| 1 | |
| 2 | package net.sourceforge.retroweaver.runtime.java.lang.annotation; |
| 3 | |
| 4 | import java.lang.reflect.InvocationHandler; |
| 5 | import java.lang.reflect.Method; |
| 6 | import java.lang.reflect.Proxy; |
| 7 | import java.util.HashMap; |
| 8 | import java.util.Map; |
| 9 | |
| 10 | /** |
| 11 | * The implementation of the Annotation interface, which gets returned from various points |
| 12 | * in java.lang.Class and java.lang.reflect.* classes. |
| 13 | * |
| 14 | * @author Toby Reyelts |
| 15 | * Date: Feb 20, 2005 |
| 16 | * Time: 11:37:18 PM |
| 17 | */ |
| 18 | public class AnnotationImpl implements InvocationHandler, Annotation { |
| 19 | |
| 20 | private final Class<? extends Annotation> annotationType_; |
| 21 | private final Map<String,Object> attributes; |
| 22 | |
| 23 | /** |
| 24 | * Called from generated bytecode to instantiate a new Annotation. |
| 25 | * Specifically, a new dynamic proxy is created with a type annotationType, |
| 26 | * and this class as the InvocationHandler. |
| 27 | * |
| 28 | * @param annotationType - The Annotation class that this AnnotationImpl should represent |
| 29 | * @param attributes - The attributes for the Annotation |
| 30 | * |
| 31 | * For example, for @Persistable, Persistable.class |
| 32 | */ |
| 33 | public static Annotation createAnnotation(final Class<? extends Annotation> annotationType, final Map<String,Object> attributes) { |
| 34 | try { |
| 35 | return (Annotation) Proxy.newProxyInstance(AnnotationImpl.class.getClassLoader(), new Class[] { Annotation.class, annotationType }, new AnnotationImpl(annotationType, attributes)); |
| 36 | } |
| 37 | catch (IllegalArgumentException e) { |
| 38 | throw new AnnotationFormatError("Unexpected exception while trying to create an annotation of type: " + annotationType, e); |
| 39 | } |
| 40 | } |
| 41 | |
| 42 | private AnnotationImpl(final Class<? extends Annotation> annotationType, final Map<String,Object> attributes) { |
| 43 | this.attributes = new HashMap<String,Object>(attributes); |
| 44 | this.annotationType_ = annotationType; |
| 45 | } |
| 46 | |
| 47 | private static final Method cloneMethod; |
| 48 | |
| 49 | static { |
| 50 | try { |
| 51 | cloneMethod = Object.class.getDeclaredMethod("clone", new Class[0]); |
| 52 | cloneMethod.setAccessible(true); |
| 53 | } catch (NoSuchMethodException e) { |
| 54 | throw new RuntimeException(e.getMessage()); |
| 55 | } |
| 56 | } |
| 57 | |
| 58 | public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable { |
| 59 | // If it's declared in the annotationType, it's an attribute |
| 60 | if (method.getDeclaringClass().equals(annotationType_)) { |
| 61 | final String name = method.getName(); |
| 62 | if (attributes.containsKey(name)) { |
| 63 | Object o = attributes.get(name); |
| 64 | if (o == null) { |
| 65 | return null; |
| 66 | } else if (o.getClass().isArray()) { |
| 67 | o = cloneMethod.invoke(o); |
| 68 | } |
| 69 | return o; |
| 70 | } |
| 71 | throw new IncompleteAnnotationException(annotationType_, name); |
| 72 | } |
| 73 | |
| 74 | // Otherwise it's something we handle innately |
| 75 | return method.invoke(this, args); |
| 76 | } |
| 77 | |
| 78 | // Returns the annotation type of this annotation. |
| 79 | public Class<? extends Annotation> annotationType() { |
| 80 | return annotationType_; |
| 81 | } |
| 82 | |
| 83 | // Returns true if the specified object represents an annotation that is logically equivalent to this one. |
| 84 | public boolean equals(final Object obj) { |
| 85 | return (obj instanceof AnnotationImpl && ((AnnotationImpl) obj).annotationType_ == annotationType_); |
| 86 | } |
| 87 | |
| 88 | // Returns the hash code of this annotation, as defined below: |
| 89 | public int hashCode() { |
| 90 | // TODO: Implement this according to spec. |
| 91 | //System.out.println("Warning: Annotation.hashCode() has yet to be implemented according to spec."); |
| 92 | //return annotationType.hashCode(); |
| 93 | return toString().hashCode(); |
| 94 | } |
| 95 | |
| 96 | // Returns a string representation of this annotation. |
| 97 | public String toString() { |
| 98 | // TODO: Implement this according to spec. |
| 99 | |
| 100 | final StringBuilder msg = new StringBuilder(); |
| 101 | msg.append('@').append(annotationType_.getName()).append('('); |
| 102 | boolean first = true; |
| 103 | for (Map.Entry<String, Object> e: attributes.entrySet()) { |
| 104 | if (first) { |
| 105 | first = false; |
| 106 | } else { |
| 107 | msg.append(", "); |
| 108 | } |
| 109 | msg.append(e.getKey()).append('='); |
| 110 | final Object o = e.getValue(); |
| 111 | if (o.getClass().isArray()) { |
| 112 | msg.append(java.util.Arrays.deepToString((Object[])o)); |
| 113 | } else { |
| 114 | msg.append(o); |
| 115 | } |
| 116 | } |
| 117 | msg.append(')'); |
| 118 | return msg.toString(); |
| 119 | } |
| 120 | |
| 121 | } |
| 122 | |