/*
* 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;
/**
* <p>
* Supports inline instantiation of annotation type instances.
* </p>
*
* <p>
* An instance of an annotation type may be obtained by subclassing <tt>AnnotationLiteral</tt>.
* </p>
*
* <pre>
* public abstract class PayByQualifier extends AnnotationLiteral<PayBy> implements PayBy {
* }
* </pre>
*
* <pre>
* PayBy payByCheque = new PayByQualifier() {
* public PaymentMethod value() {
* return CHEQUE;
* }
* };
* </pre>
*
* @author Pete Muir
* @author Gavin King
* @author Marko Luksa
*
* @param <T> the annotation type
*
* @see javax.enterprise.inject.Instance#select(Annotation...)
* @see javax.enterprise.event.Event#select(Annotation...)
*
*/
public abstract class AnnotationLiteral<T extends Annotation> implements Annotation, Serializable {
private static final long serialVersionUID = 1L;
private transient Class<T> 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 <T> Class<T> getTypeParameter(Class<?> annotationLiteralSuperclass) {
Type type = annotationLiteralSuperclass.getGenericSuperclass();
if (type instanceof ParameterizedType) {
ParameterizedType parameterizedType = (ParameterizedType) type;
if (parameterizedType.getActualTypeArguments().length == 1) {
return (Class<T>) parameterizedType.getActualTypeArguments()[0];
}
}
return null;
}
public Class<? extends Annotation> 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<T>");
}
}
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 | IllegalAccessException | InvocationTargetException e) {
throw new RuntimeException("Error checking value of member method " + method.getName() + " on "
+ method.getDeclaringClass(), e);
}
}
}