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/*
 * JBoss, Home of Professional Open Source
 * Copyright 2010, Red Hat, Inc., and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package javax.enterprise.util;

import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Arrays;

/**
 * 

* Supports inline instantiation of annotation type instances. *

* *

* An instance of an annotation type may be obtained by subclassing AnnotationLiteral. *

* *
 * public abstract class PayByQualifier extends AnnotationLiteral<PayBy> implements PayBy {
 * }
 * 
* *
 * PayBy paybyCheque = new PayByQualifier() {
 *     public PaymentMethod value() {
 *         return CHEQUE;
 *     }
 * };
 * 
* * @author Pete Muir * @author Gavin King * @author Marko Luksa * * @param the annotation type * * @see javax.enterprise.inject.Instance#select(Annotation...) * @see javax.enterprise.event.Event#select(Annotation...) * */ public abstract class AnnotationLiteral implements Annotation, Serializable { private static final long serialVersionUID = 1L; private transient Class annotationType; private transient Method[] members; private transient Integer cachedHashCode; protected AnnotationLiteral() { if (getMembers().length == 0) { this.cachedHashCode = 0; } else { this.cachedHashCode = null; } } private Method[] getMembers() { if (members == null) { members = annotationType().getDeclaredMethods(); if (members.length > 0 && !annotationType().isAssignableFrom(this.getClass())) { throw new RuntimeException(getClass() + " does not implement the annotation type with members " + annotationType().getName()); } } return members; } private static Class getAnnotationLiteralSubclass(Class clazz) { Class superclass = clazz.getSuperclass(); if (superclass.equals(AnnotationLiteral.class)) { return clazz; } else if (superclass.equals(Object.class)) { return null; } else { return (getAnnotationLiteralSubclass(superclass)); } } @SuppressWarnings("unchecked") private static Class getTypeParameter(Class annotationLiteralSuperclass) { Type type = annotationLiteralSuperclass.getGenericSuperclass(); if (type instanceof ParameterizedType) { ParameterizedType parameterizedType = (ParameterizedType) type; if (parameterizedType.getActualTypeArguments().length == 1) { return (Class) parameterizedType.getActualTypeArguments()[0]; } } return null; } public Class annotationType() { if (annotationType == null) { Class annotationLiteralSubclass = getAnnotationLiteralSubclass(this.getClass()); if (annotationLiteralSubclass == null) { throw new RuntimeException(getClass() + " is not a subclass of AnnotationLiteral"); } annotationType = getTypeParameter(annotationLiteralSubclass); if (annotationType == null) { throw new RuntimeException(getClass() + " does not specify the type parameter T of AnnotationLiteral"); } } return annotationType; } @Override public String toString() { StringBuilder string = new StringBuilder(); string.append('@').append(annotationType().getName()).append('('); for (int i = 0; i < getMembers().length; i++) { string.append(getMembers()[i].getName()).append('='); Object value = getMemberValue(getMembers()[i], this); if (value instanceof boolean[]) { appendInBraces(string, Arrays.toString((boolean[]) value)); } else if (value instanceof byte[]) { appendInBraces(string, Arrays.toString((byte[]) value)); } else if (value instanceof short[]) { appendInBraces(string, Arrays.toString((short[]) value)); } else if (value instanceof int[]) { appendInBraces(string, Arrays.toString((int[]) value)); } else if (value instanceof long[]) { appendInBraces(string, Arrays.toString((long[]) value)); } else if (value instanceof float[]) { appendInBraces(string, Arrays.toString((float[]) value)); } else if (value instanceof double[]) { appendInBraces(string, Arrays.toString((double[]) value)); } else if (value instanceof char[]) { appendInBraces(string, Arrays.toString((char[]) value)); } else if (value instanceof String[]) { String[] strings = (String[]) value; String[] quoted = new String[strings.length]; for (int j = 0; j < strings.length; j++) { quoted[j] = "\"" + strings[j] + "\""; } appendInBraces(string, Arrays.toString(quoted)); } else if (value instanceof Class[]) { Class[] classes = (Class[]) value; String[] names = new String[classes.length]; for (int j = 0; j < classes.length; j++) { names[j] = classes[j].getName() + ".class"; } appendInBraces(string, Arrays.toString(names)); } else if (value instanceof Object[]) { appendInBraces(string, Arrays.toString((Object[]) value)); } else if (value instanceof String) { string.append('"').append(value).append('"'); } else if (value instanceof Class) { string.append(((Class) value).getName()).append(".class"); } else { string.append(value); } if (i < getMembers().length - 1) { string.append(", "); } } return string.append(')').toString(); } private void appendInBraces(StringBuilder buf, String s) { buf.append('{').append(s.substring(1, s.length() - 1)).append('}'); } @Override public boolean equals(Object other) { if (other == this) { return true; } if (other == null) { return false; } if (other instanceof Annotation) { Annotation that = (Annotation) other; if (this.annotationType().equals(that.annotationType())) { for (Method member : getMembers()) { Object thisValue = getMemberValue(member, this); Object thatValue = getMemberValue(member, that); if (thisValue instanceof byte[] && thatValue instanceof byte[]) { if (!Arrays.equals((byte[]) thisValue, (byte[]) thatValue)) return false; } else if (thisValue instanceof short[] && thatValue instanceof short[]) { if (!Arrays.equals((short[]) thisValue, (short[]) thatValue)) return false; } else if (thisValue instanceof int[] && thatValue instanceof int[]) { if (!Arrays.equals((int[]) thisValue, (int[]) thatValue)) return false; } else if (thisValue instanceof long[] && thatValue instanceof long[]) { if (!Arrays.equals((long[]) thisValue, (long[]) thatValue)) return false; } else if (thisValue instanceof float[] && thatValue instanceof float[]) { if (!Arrays.equals((float[]) thisValue, (float[]) thatValue)) return false; } else if (thisValue instanceof double[] && thatValue instanceof double[]) { if (!Arrays.equals((double[]) thisValue, (double[]) thatValue)) return false; } else if (thisValue instanceof char[] && thatValue instanceof char[]) { if (!Arrays.equals((char[]) thisValue, (char[]) thatValue)) return false; } else if (thisValue instanceof boolean[] && thatValue instanceof boolean[]) { if (!Arrays.equals((boolean[]) thisValue, (boolean[]) thatValue)) return false; } else if (thisValue instanceof Object[] && thatValue instanceof Object[]) { if (!Arrays.equals((Object[]) thisValue, (Object[]) thatValue)) return false; } else { if (!thisValue.equals(thatValue)) return false; } } return true; } } return false; } @Override public int hashCode() { if (cachedHashCode != null) { return cachedHashCode; } else { int hashCode = 0; for (Method member : getMembers()) { int memberNameHashCode = 127 * member.getName().hashCode(); Object value = getMemberValue(member, this); int memberValueHashCode; if (value instanceof boolean[]) { memberValueHashCode = Arrays.hashCode((boolean[]) value); } else if (value instanceof short[]) { memberValueHashCode = Arrays.hashCode((short[]) value); } else if (value instanceof int[]) { memberValueHashCode = Arrays.hashCode((int[]) value); } else if (value instanceof long[]) { memberValueHashCode = Arrays.hashCode((long[]) value); } else if (value instanceof float[]) { memberValueHashCode = Arrays.hashCode((float[]) value); } else if (value instanceof double[]) { memberValueHashCode = Arrays.hashCode((double[]) value); } else if (value instanceof byte[]) { memberValueHashCode = Arrays.hashCode((byte[]) value); } else if (value instanceof char[]) { memberValueHashCode = Arrays.hashCode((char[]) value); } else if (value instanceof Object[]) { memberValueHashCode = Arrays.hashCode((Object[]) value); } else { memberValueHashCode = value.hashCode(); } hashCode += memberNameHashCode ^ memberValueHashCode; } return hashCode; } } private static Object getMemberValue(Method member, Annotation instance) { Object value = invoke(member, instance); if (value == null) { throw new IllegalArgumentException("Annotation member value " + instance.getClass().getName() + "." + member.getName() + " must not be null"); } return value; } private static Object invoke(Method method, Object instance) { try { if (!method.isAccessible()) method.setAccessible(true); return method.invoke(instance); } catch (IllegalArgumentException e) { throw new RuntimeException("Error checking value of member method " + method.getName() + " on " + method.getDeclaringClass(), e); } catch (IllegalAccessException e) { throw new RuntimeException("Error checking value of member method " + method.getName() + " on " + method.getDeclaringClass(), e); } catch (InvocationTargetException e) { throw new RuntimeException("Error checking value of member method " + method.getName() + " on " + method.getDeclaringClass(), e); } } }




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