/*

 * Copyright (c) 2008, 2012, Oracle and/or its affiliates. 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.beans.finder;

import java.lang.reflect.Field;

import java.lang.reflect.Modifier;

import static sun.reflect.misc.ReflectUtil.isPackageAccessible;

/**

 * This utility class provides {@code static} methods

 * to find a public field with specified name

 * in specified class.

 *

 * @since 1.7

 *

 * @author Sergey A. Malenkov

 */

public final class FieldFinder {

    /**

     * Finds public field (static or non-static)

     * that is declared in public class.

     *

     * @param type  the class that can have field

     * @param name  the name of field to find

     * @return object that represents found field

     * @throws NoSuchFieldException if field is not found

     * @see Class#getField

     */

    public static Field findField(Class<?> type, String name) throws NoSuchFieldException {

        if (name == null) {

            throw new IllegalArgumentException("Field name is not set");

        }

        Field field = type.getField(name);

        if (!Modifier.isPublic(field.getModifiers())) {

            throw new NoSuchFieldException("Field '" + name + "' is not public");

        }

        type = field.getDeclaringClass();

        if (!Modifier.isPublic(type.getModifiers()) || !isPackageAccessible(type)) {

            throw new NoSuchFieldException("Field '" + name + "' is not accessible");

        }

        return field;

    }

    /**

     * Finds public non-static field

     * that is declared in public class.

     *

     * @param type  the class that can have field

     * @param name  the name of field to find

     * @return object that represents found field

     * @throws NoSuchFieldException if field is not found

     * @see Class#getField

     */

    public static Field findInstanceField(Class<?> type, String name) throws NoSuchFieldException {

        Field field = findField(type, name);

        if (Modifier.isStatic(field.getModifiers())) {

            throw new NoSuchFieldException("Field '" + name + "' is static");

        }

        return field;

    }

    /**

     * Finds public static field

     * that is declared in public class.

     *

     * @param type  the class that can have field

     * @param name  the name of field to find

     * @return object that represents found field

     * @throws NoSuchFieldException if field is not found

     * @see Class#getField

     */

    public static Field findStaticField(Class<?> type, String name) throws NoSuchFieldException {

        Field field = findField(type, name);

        if (!Modifier.isStatic(field.getModifiers())) {

            throw new NoSuchFieldException("Field '" + name + "' is not static");

        }

        return field;

    }

    /**

     * Disable instantiation.

     */

    private FieldFinder() {

    }

}