/*

 * Copyright (c) 2016, 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 sun.util.resources;

import java.io.InputStream;

import java.security.AccessController;

import java.security.PrivilegedActionException;

import java.security.PrivilegedExceptionAction;

import java.util.Collections;

import java.util.Enumeration;

import java.util.ResourceBundle;

import java.util.Set;

/**

 * BreakIteratorResourceBundle is an abstract class for loading BreakIterator

 * data (rules or dictionary) from each module. An implementation class must

 * implement getBreakIteratorInfo() that returns an instance of the

 * corresponding BreakIteratorInfo (basename).  The data name is taken from the

 * BreakIteratorInfo instance.

 *

 * <p>For example, if the given key is "WordDictionary" and Locale is "th", the

 * data name is taken from a BreakIteratorInfo_th and the key's value is

 * "thai_dict".  Its data thai_dict is loaded from the Module of the

 * implementation class of this class.

 */

public abstract class BreakIteratorResourceBundle extends ResourceBundle {

    // If any keys that are not for data names are added to BreakIteratorInfo*,

    // those keys must be added to NON_DATA_KEYS.

    private static final Set<String> NON_DATA_KEYS = Set.of("BreakIteratorClasses");

    private volatile Set<String> keys;

    /**

     * Returns an instance of the corresponding {@code BreakIteratorInfo} (basename).

     * The instance shouldn't have its parent.

     */

    protected abstract ResourceBundle getBreakIteratorInfo();

    @Override

    protected Object handleGetObject(String key) {

        if (NON_DATA_KEYS.contains(key)) {

            return null;

        }

        ResourceBundle info = getBreakIteratorInfo();

        if (!info.containsKey(key)) {

            return null;

        }

        String path = getClass().getPackageName().replace('.', '/')

                      + '/' + info.getString(key);

        byte[] data;

        try (InputStream is = getResourceAsStream(path)) {

            data = is.readAllBytes();

        } catch (Exception e) {

            throw new InternalError("Can't load " + path, e);

        }

        return data;

    }

    private InputStream getResourceAsStream(String path) throws Exception {

        PrivilegedExceptionAction<InputStream> pa;

        pa = () -> getClass().getModule().getResourceAsStream(path);

        InputStream is;

        try {

            is = AccessController.doPrivileged(pa);

        } catch (PrivilegedActionException e) {

            throw e.getException();

        }

        return is;

    }

    @Override

    public Enumeration<String> getKeys() {

        return Collections.enumeration(keySet());

    }

    @Override

    protected Set<String> handleKeySet() {

        if (keys == null) {

            ResourceBundle info = getBreakIteratorInfo();

            Set<String> k = info.keySet();

            k.removeAll(NON_DATA_KEYS);

            synchronized (this) {

                if (keys == null) {

                    keys = k;

                }

            }

        }

        return keys;

    }

}