org.springframework.beans.factory.support.AutowireUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2006 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.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Set;
import org.springframework.util.ClassUtils;
/**
* Utility class that contains various methods useful for
* the implementation of autowire-capable bean factories.
*
* @author Juergen Hoeller
* @since 1.1.2
* @see AbstractAutowireCapableBeanFactory
*/
abstract class AutowireUtils {
/**
* Sort the given constructors, preferring public constructors and "greedy" ones
* with a maximum 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() {
public int compare(Object o1, Object o2) {
Constructor c1 = (Constructor) o1;
Constructor c2 = (Constructor) o2;
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(new Integer(c2pl)) * -1;
}
});
}
/**
* Determine a weight that represents the class hierarchy difference between types and
* arguments. A direct match, i.e. type Integer -> arg of class Integer, does not increase
* the result - all direct matches means weight 0. A match between type Object and arg of
* class Integer would increase the weight by 2, due to the superclass 2 steps up in the
* hierarchy (i.e. Object) being the last one that still matches the required type Object.
* Type Number and class Integer would increase the weight by 1 accordingly, due to the
* superclass 1 step up the hierarchy (i.e. Number) still matching the required type Number.
* Therefore, with an arg of type Integer, a constructor (Integer) would be preferred to a
* constructor (Number) which would in turn be preferred to a constructor (Object).
* All argument weights get accumulated.
* @param paramTypes the parameter types to match
* @param args the arguments to match
* @return the accumulated weight for all arguments
*/
public static int getTypeDifferenceWeight(Class[] paramTypes, Object[] args) {
int result = 0;
for (int i = 0; i < paramTypes.length; i++) {
if (!ClassUtils.isAssignableValue(paramTypes[i], args[i])) {
return Integer.MAX_VALUE;
}
if (args[i] != null) {
Class superClass = args[i].getClass().getSuperclass();
while (superClass != null) {
if (ClassUtils.isAssignable(paramTypes[i], superClass)) {
result++;
superClass = superClass.getSuperclass();
}
else {
superClass = null;
}
}
}
}
return result;
}
/**
* Determine whether the given bean property is excluded from dependency checks.
* 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().indexOf("$$") == -1) {
// 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 interfaces) {
Method setter = pd.getWriteMethod();
if (setter != null) {
Class targetClass = setter.getDeclaringClass();
for (Iterator it = interfaces.iterator(); it.hasNext();) {
Class ifc = (Class) it.next();
if (ifc.isAssignableFrom(targetClass) &&
ClassUtils.hasMethod(ifc, setter.getName(), setter.getParameterTypes())) {
return true;
}
}
}
return false;
}
}