com.google.gwt.dev.javac.AnnotationProxyFactory Maven / Gradle / Ivy
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/*
* Copyright 2008 Google Inc.
*
* 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 com.google.gwt.dev.javac;
import com.google.gwt.dev.util.collect.Maps;
import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.Map;
/**
* Creates proxies for annotation objects that...
*/
class AnnotationProxyFactory {
/**
* {@link InvocationHandler} implementation used by all
* {@link java.lang.annotation.Annotation Annotation} proxies created by the
* {@link TypeOracle}.
*/
private static class AnnotationProxyInvocationHandler implements
InvocationHandler {
/**
* Returns true if the expected return type is assignable
* from the actual return type or if the expected return type is a primitive
* and the actual return type is the corresponding wrapper type.
*/
private static boolean isValidReturnType(Class expectedReturnType,
Class actualReturnType) {
if (expectedReturnType.isAssignableFrom(actualReturnType)) {
return true;
}
if (expectedReturnType.isPrimitive()) {
if (expectedReturnType == boolean.class) {
return actualReturnType == Boolean.class;
} else if (expectedReturnType == byte.class) {
return actualReturnType == Byte.class;
} else if (expectedReturnType == char.class) {
return actualReturnType == Character.class;
} else if (expectedReturnType == double.class) {
return actualReturnType == Double.class;
} else if (expectedReturnType == float.class) {
return actualReturnType == Float.class;
} else if (expectedReturnType == int.class) {
return actualReturnType == Integer.class;
} else if (expectedReturnType == long.class) {
return actualReturnType == Long.class;
} else if (expectedReturnType == short.class) {
return actualReturnType == Short.class;
}
}
return false;
}
/**
* The resolved class of this annotation.
*/
private Class annotationClass;
/**
* Maps method names onto values. Note that methods on annotation types
* cannot be overloaded because they have zero arguments.
*/
private final Map identifierToValue;
/**
* A reference to the enclosing proxy object.
*/
private Annotation proxy;
public AnnotationProxyInvocationHandler(
Map identifierToValue,
Class annotationClass) {
this.identifierToValue = Maps.normalizeUnmodifiable(identifierToValue);
this.annotationClass = annotationClass;
}
@Override
public boolean equals(Object other) {
// This is not actually an asymmetric equals implementation, as this
// method gets called for our proxy instance rather than on the handler
// itself.
if (proxy == other) {
return true;
}
if (!(other instanceof Annotation)) {
return false;
}
Annotation otherAnnotation = (Annotation) other;
if (annotationClass != otherAnnotation.annotationType()) {
return false;
}
try {
for (Method method : annotationClass.getDeclaredMethods()) {
Object myVal = method.invoke(proxy);
Object otherVal = method.invoke(other);
if (myVal instanceof Object[]) {
if (!Arrays.equals((Object[]) myVal, (Object[]) otherVal)) {
return false;
}
} else if (myVal instanceof boolean[]) {
if (!Arrays.equals((boolean[]) myVal, (boolean[]) otherVal)) {
return false;
}
} else if (myVal instanceof byte[]) {
if (!Arrays.equals((byte[]) myVal, (byte[]) otherVal)) {
return false;
}
} else if (myVal instanceof char[]) {
if (!Arrays.equals((char[]) myVal, (char[]) otherVal)) {
return false;
}
} else if (myVal instanceof short[]) {
if (!Arrays.equals((short[]) myVal, (short[]) otherVal)) {
return false;
}
} else if (myVal instanceof int[]) {
if (!Arrays.equals((int[]) myVal, (int[]) otherVal)) {
return false;
}
} else if (myVal instanceof long[]) {
if (!Arrays.equals((long[]) myVal, (long[]) otherVal)) {
return false;
}
} else if (myVal instanceof float[]) {
if (!Arrays.equals((float[]) myVal, (float[]) otherVal)) {
return false;
}
} else if (myVal instanceof double[]) {
if (!Arrays.equals((double[]) myVal, (double[]) otherVal)) {
return false;
}
} else {
if (!myVal.equals(otherVal)) {
return false;
}
}
}
} catch (IllegalArgumentException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
} catch (InvocationTargetException e) {
throw new RuntimeException(e.getTargetException());
}
return true;
}
@Override
public int hashCode() {
int sum = 0;
try {
for (Method method : annotationClass.getDeclaredMethods()) {
Object myVal = method.invoke(proxy);
int memberHash;
if (myVal instanceof Object[]) {
memberHash = Arrays.hashCode((Object[]) myVal);
} else if (myVal instanceof boolean[]) {
memberHash = Arrays.hashCode((boolean[]) myVal);
} else if (myVal instanceof byte[]) {
memberHash = Arrays.hashCode((byte[]) myVal);
} else if (myVal instanceof char[]) {
memberHash = Arrays.hashCode((char[]) myVal);
} else if (myVal instanceof short[]) {
memberHash = Arrays.hashCode((short[]) myVal);
} else if (myVal instanceof int[]) {
memberHash = Arrays.hashCode((int[]) myVal);
} else if (myVal instanceof long[]) {
memberHash = Arrays.hashCode((long[]) myVal);
} else if (myVal instanceof float[]) {
memberHash = Arrays.hashCode((float[]) myVal);
} else if (myVal instanceof double[]) {
memberHash = Arrays.hashCode((double[]) myVal);
} else {
memberHash = myVal.hashCode();
}
// See doc for Annotation.hashCode.
memberHash ^= 127 * method.getName().hashCode();
sum += memberHash;
}
} catch (IllegalArgumentException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
} catch (InvocationTargetException e) {
throw new RuntimeException(e.getTargetException());
}
return sum;
}
/*
* (non-Javadoc)
*
* @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object,
* java.lang.reflect.Method, java.lang.Object[])
*/
@Override
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
Object value = null;
if (args == null || args.length == 0) {
// A no-arg method, try to process as an annotation method.
String name = method.getName();
if (identifierToValue.containsKey(name)) {
// The value was explicitly provided
value = identifierToValue.get(name);
assert (value != null);
} else {
if ("annotationType".equals(method.getName())) {
value = annotationClass;
} else {
value = method.getDefaultValue();
}
}
if (value != null) {
assert (isValidReturnType(method.getReturnType(), value.getClass()));
return value;
}
}
/*
* Maybe it's an Object method, just delegate to myself.
*/
return method.invoke(this, args);
}
public void setProxy(Annotation proxy) {
this.proxy = proxy;
}
@Override
public String toString() {
final StringBuilder msg = new StringBuilder();
String qualifiedSourceName = annotationClass.getName().replace('$', '.');
msg.append('@').append(qualifiedSourceName).append('(');
boolean first = true;
try {
for (Method method : annotationClass.getDeclaredMethods()) {
if (first) {
first = false;
} else {
msg.append(", ");
}
msg.append(method.getName()).append('=');
Object myVal = method.invoke(proxy);
if (myVal instanceof Object[]) {
msg.append(Arrays.deepToString((Object[]) myVal));
} else if (myVal instanceof boolean[]) {
msg.append(Arrays.toString((boolean[]) myVal));
} else if (myVal instanceof byte[]) {
msg.append(Arrays.toString((byte[]) myVal));
} else if (myVal instanceof char[]) {
msg.append(Arrays.toString((char[]) myVal));
} else if (myVal instanceof short[]) {
msg.append(Arrays.toString((short[]) myVal));
} else if (myVal instanceof int[]) {
msg.append(Arrays.toString((int[]) myVal));
} else if (myVal instanceof long[]) {
msg.append(Arrays.toString((long[]) myVal));
} else if (myVal instanceof float[]) {
msg.append(Arrays.toString((float[]) myVal));
} else if (myVal instanceof double[]) {
msg.append(Arrays.toString((double[]) myVal));
} else {
msg.append(myVal);
}
}
} catch (IllegalArgumentException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
} catch (InvocationTargetException e) {
throw new RuntimeException(e.getTargetException());
}
msg.append(')');
return msg.toString();
}
}
public static Annotation create(Class annotationClass,
Map identifierToValue) {
AnnotationProxyInvocationHandler annotationInvocationHandler = new AnnotationProxyInvocationHandler(
identifierToValue, annotationClass);
Annotation proxy = (Annotation) Proxy.newProxyInstance(
Thread.currentThread().getContextClassLoader(), new Class[] {
java.lang.annotation.Annotation.class, annotationClass},
annotationInvocationHandler);
annotationInvocationHandler.setProxy(proxy);
return proxy;
}
}