/*
* Copyright 2002-2010 the original author or authors.
*
* 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 org.springframework.beans.factory.support;
import java.beans.PropertyDescriptor;
import java.io.Serializable;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Set;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.util.ClassUtils;
/**
* Utility class that contains various methods useful for
* the implementation of autowire-capable bean factories.
*
* @author Juergen Hoeller
* @author Mark Fisher
* @since 1.1.2
* @see AbstractAutowireCapableBeanFactory
*/
abstract class AutowireUtils {
/**
* Sort the given constructors, preferring public constructors and "greedy" ones with
* a maximum number of arguments. The result will contain public constructors first,
* with decreasing number of arguments, then non-public constructors, again with
* decreasing number of arguments.
* @param constructors the constructor array to sort
*/
public static void sortConstructors(Constructor[] constructors) {
Arrays.sort(constructors, new Comparator<Constructor>() {
public int compare(Constructor c1, Constructor c2) {
boolean p1 = Modifier.isPublic(c1.getModifiers());
boolean p2 = Modifier.isPublic(c2.getModifiers());
if (p1 != p2) {
return (p1 ? -1 : 1);
}
int c1pl = c1.getParameterTypes().length;
int c2pl = c2.getParameterTypes().length;
return (new Integer(c1pl)).compareTo(c2pl) * -1;
}
});
}
/**
* Sort the given factory methods, preferring public methods and "greedy" ones
* with a maximum of arguments. The result will contain public methods first,
* with decreasing number of arguments, then non-public methods, again with
* decreasing number of arguments.
* @param factoryMethods the factory method array to sort
*/
public static void sortFactoryMethods(Method[] factoryMethods) {
Arrays.sort(factoryMethods, new Comparator<Method>() {
public int compare(Method fm1, Method fm2) {
boolean p1 = Modifier.isPublic(fm1.getModifiers());
boolean p2 = Modifier.isPublic(fm2.getModifiers());
if (p1 != p2) {
return (p1 ? -1 : 1);
}
int c1pl = fm1.getParameterTypes().length;
int c2pl = fm2.getParameterTypes().length;
return (new Integer(c1pl)).compareTo(c2pl) * -1;
}
});
}
/**
* Determine whether the given bean property is excluded from dependency checks.
* <p>This implementation excludes properties defined by CGLIB.
* @param pd the PropertyDescriptor of the bean property
* @return whether the bean property is excluded
*/
public static boolean isExcludedFromDependencyCheck(PropertyDescriptor pd) {
Method wm = pd.getWriteMethod();
if (wm == null) {
return false;
}
if (!wm.getDeclaringClass().getName().contains("$$")) {
// Not a CGLIB method so it's OK.
return false;
}
// It was declared by CGLIB, but we might still want to autowire it
// if it was actually declared by the superclass.
Class superclass = wm.getDeclaringClass().getSuperclass();
return !ClassUtils.hasMethod(superclass, wm.getName(), wm.getParameterTypes());
}
/**
* Return whether the setter method of the given bean property is defined
* in any of the given interfaces.
* @param pd the PropertyDescriptor of the bean property
* @param interfaces the Set of interfaces (Class objects)
* @return whether the setter method is defined by an interface
*/
public static boolean isSetterDefinedInInterface(PropertyDescriptor pd, Set<Class> interfaces) {
Method setter = pd.getWriteMethod();
if (setter != null) {
Class targetClass = setter.getDeclaringClass();
for (Class ifc : interfaces) {
if (ifc.isAssignableFrom(targetClass) &&
ClassUtils.hasMethod(ifc, setter.getName(), setter.getParameterTypes())) {
return true;
}
}
}
return false;
}
/**
* Resolve the given autowiring value against the given required type,
* e.g. an {@link ObjectFactory} value to its actual object result.
* @param autowiringValue the value to resolve
* @param requiredType the type to assign the result to
* @return the resolved value
*/
public static Object resolveAutowiringValue(Object autowiringValue, Class requiredType) {
if (autowiringValue instanceof ObjectFactory && !requiredType.isInstance(autowiringValue)) {
ObjectFactory factory = (ObjectFactory) autowiringValue;
if (autowiringValue instanceof Serializable && requiredType.isInterface()) {
autowiringValue = Proxy.newProxyInstance(requiredType.getClassLoader(),
new Class[] {requiredType}, new ObjectFactoryDelegatingInvocationHandler(factory));
}
else {
return factory.getObject();
}
}
return autowiringValue;
}
/**
* Reflective InvocationHandler for lazy access to the current target object.
*/
private static class ObjectFactoryDelegatingInvocationHandler implements InvocationHandler, Serializable {
private final ObjectFactory objectFactory;
public ObjectFactoryDelegatingInvocationHandler(ObjectFactory objectFactory) {
this.objectFactory = objectFactory;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
String methodName = method.getName();
if (methodName.equals("equals")) {
// Only consider equal when proxies are identical.
return (proxy == args[0]);
}
else if (methodName.equals("hashCode")) {
// Use hashCode of proxy.
return System.identityHashCode(proxy);
}
else if (methodName.equals("toString")) {
return this.objectFactory.toString();
}
try {
return method.invoke(this.objectFactory.getObject(), args);
}
catch (InvocationTargetException ex) {
throw ex.getTargetException();
}
}
}
}