/*

 * 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);

    }

}