/*
* Copyright 2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package com.sun.beans.finder;
import com.sun.beans.WeakCache;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
/**
* This utility class provides {@code static} methods
* to find a public method with specified name and parameter types
* in specified class.
*
* @since 1.7
*
* @author Sergey A. Malenkov
*/
public final class MethodFinder extends AbstractFinder<Method> {
private static final WeakCache<Signature, Method> CACHE = new WeakCache<Signature, Method>();
/**
* Finds public method (static or non-static)
* that is accessible from public class.
*
* @param type the class that can have method
* @param name the name of method to find
* @param args parameter types that is used to find method
* @return object that represents found method
* @throws NoSuchMethodException if method could not be found
* or some methods are found
*/
public static Method findMethod(Class<?> type, String name, Class<?>...args) throws NoSuchMethodException {
if (name == null) {
throw new IllegalArgumentException("Method name is not set");
}
PrimitiveWrapperMap.replacePrimitivesWithWrappers(args);
Signature signature = new Signature(type, name, args);
Method method = CACHE.get(signature);
if (method != null) {
return method;
}
method = findAccessibleMethod(new MethodFinder(name, args).find(type.getMethods()));
CACHE.put(signature, method);
return method;
}
/**
* Finds public non-static method
* that is accessible from public class.
*
* @param type the class that can have method
* @param name the name of method to find
* @param args parameter types that is used to find method
* @return object that represents found method
* @throws NoSuchMethodException if method could not be found
* or some methods are found
*/
public static Method findInstanceMethod(Class<?> type, String name, Class<?>... args) throws NoSuchMethodException {
Method method = findMethod(type, name, args);
if (Modifier.isStatic(method.getModifiers())) {
throw new NoSuchMethodException("Method '" + name + "' is static");
}
return method;
}
/**
* Finds public static method
* that is accessible from public class.
*
* @param type the class that can have method
* @param name the name of method to find
* @param args parameter types that is used to find method
* @return object that represents found method
* @throws NoSuchMethodException if method could not be found
* or some methods are found
*/
public static Method findStaticMethod(Class<?> type, String name, Class<?>...args) throws NoSuchMethodException {
Method method = findMethod(type, name, args);
if (!Modifier.isStatic(method.getModifiers())) {
throw new NoSuchMethodException("Method '" + name + "' is not static");
}
return method;
}
/**
* Finds method that is accessible from public class or interface through class hierarchy.
*
* @param method object that represents found method
* @return object that represents accessible method
* @throws NoSuchMethodException if method is not accessible or is not found
* in specified superclass or interface
*/
private static Method findAccessibleMethod(Method method) throws NoSuchMethodException {
Class<?> type = method.getDeclaringClass();
if (Modifier.isPublic(type.getModifiers())) {
return method;
}
if (Modifier.isStatic(method.getModifiers())) {
throw new NoSuchMethodException("Method '" + method.getName() + "' is not accessible");
}
for (Class<?> face : type.getInterfaces()) {
try {
return findAccessibleMethod(method, face);
}
catch (NoSuchMethodException exception) {
// try to find in superclass or another interface
}
}
return findAccessibleMethod(method, type.getSuperclass());
}
/**
* Finds method that accessible from specified class.
*
* @param method object that represents found method
* @param type class that is used to find accessible method
* @return object that represents accessible method
* @throws NoSuchMethodException if method is not accessible or is not found
* in specified superclass or interface
*/
private static Method findAccessibleMethod(Method method, Class<?> type) throws NoSuchMethodException {
String name = method.getName();
Class<?>[] params = method.getParameterTypes();
return findAccessibleMethod(type.getMethod(name, params));
}
private final String name;
/**
* Creates method finder with specified array of parameter types.
*
* @param name the name of method to find
* @param args the array of parameter types
*/
private MethodFinder(String name, Class<?>[] args) {
super(args);
this.name = name;
}
/**
* Returns an array of {@code Class} objects
* that represent the formal parameter types of the method
* Returns an empty array if the method takes no parameters.
*
* @param method the object that represents method
* @return the parameter types of the method
*/
@Override
protected Class<?>[] getParameters(Method method) {
return method.getParameterTypes();
}
/**
* Returns {@code true} if and only if the method
* was declared to take a variable number of arguments.
*
* @param method the object that represents method
* @return {@code true} if the method was declared
* to take a variable number of arguments;
* {@code false} otherwise
*/
@Override
protected boolean isVarArgs(Method method) {
return method.isVarArgs();
}
/**
* Checks validness of the method.
* The valid method should be public and
* should have the specified name.
*
* @param method the object that represents method
* @return {@code true} if the method is valid,
* {@code false} otherwise
*/
@Override
protected boolean isValid(Method method) {
return Modifier.isPublic(method.getModifiers()) && method.getName().equals(this.name);
}
}