/*

 * Copyright (c) 2009, 2010, 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;

/**

 * This is utility class that provides basic functionality

 * to find an auxiliary class for a JavaBean specified by its type.

 *

 * @since 1.7

 *

 * @author Sergey A. Malenkov

 */

class InstanceFinder<T> {

    private static final String[] EMPTY = { };

    private final Class<? extends T> type;

    private final boolean allow;

    private final String suffix;

    private volatile String[] packages;

    InstanceFinder(Class<? extends T> type, boolean allow, String suffix, String... packages) {

        this.type = type;

        this.allow = allow;

        this.suffix = suffix;

        this.packages = packages.clone();

    }

    public String[] getPackages() {

        return this.packages.clone();

    }

    public void setPackages(String... packages) {

        this.packages = (packages != null) && (packages.length > 0)

                ? packages.clone()

                : EMPTY;

    }

    public T find(Class<?> type) {

        if (type == null) {

            return null;

        }

        String name = type.getName() + this.suffix;

        T object = instantiate(type, name);

        if (object != null) {

            return object;

        }

        if (this.allow) {

            object = instantiate(type, null);

            if (object != null) {

                return object;

            }

        }

        int index = name.lastIndexOf('.') + 1;

        if (index > 0) {

            name = name.substring(index);

        }

        for (String prefix : this.packages) {

            object = instantiate(type, prefix, name);

            if (object != null) {

                return object;

            }

        }

        return null;

    }

    protected T instantiate(Class<?> type, String name) {

        if (type != null) {

            try {

                if (name != null) {

                    type = ClassFinder.findClass(name, type.getClassLoader());

                }

                if (this.type.isAssignableFrom(type)) {

                    return (T) type.newInstance();

                }

            }

            catch (Exception exception) {

                // ignore any exceptions

            }

        }

        return null;

    }

    protected T instantiate(Class<?> type, String prefix, String name) {

        return instantiate(type, prefix + '.' + name);

    }

}