/*
 * 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
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 * 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.
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.
/**
 * 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 BreakIteratorInfo (basename). The instance shouldn't have its parent. /**
     * 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;
    }
}