/*
 * Copyright (c) 2014, 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.
 *
 * 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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 */

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Field;
import java.util.Hashtable;

/**
 * @test
 * @bug 8068427
 * @summary Hashtable deserialization reconstitutes table with wrong capacity
 */
public class DeserializedLength {

    static boolean testDeserializedLength(int elements) throws Exception {
        // construct Hashtable
        float loadFactor = 0.75f;
        Hashtable<Integer, Integer> ht1 = new Hashtable<>(
            (int) (elements / loadFactor) + 1,
            loadFactor
        );
        for (int i = 0; i < elements; i++) {
            ht1.put(i, i);
        }

        // serialize it to byte[] array
        byte[] bytes;
        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
             ObjectOutputStream oos = new ObjectOutputStream(baos)) {
            oos.writeObject(ht1);
            oos.flush();
            bytes = baos.toByteArray();
        }

        // de-serialize it from byte[] array
        Hashtable<?, ?> ht2;
        try (ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
             ObjectInputStream ois = new ObjectInputStream(bais)) {
            ht2 = (Hashtable<?, ?>) ois.readObject();
        }

        // compare lengths of internal tables
        Object[] table1 = (Object[]) hashtableTableField.get(ht1);
        Object[] table2 = (Object[]) hashtableTableField.get(ht2);

        System.out.println("Serialized Hashtable of size=" + ht1.size() +
            " has internal table.length=" + table1.length +
            " de-serialized table.length=" + table2.length);

        return table2.length >= table1.length;
    }

    private static final Field hashtableTableField;

    static {
        try {
            hashtableTableField = Hashtable.class.getDeclaredField("table");
            hashtableTableField.setAccessible(true);
        } catch (NoSuchFieldException e) {
            throw new Error(e);
        }
    }

    public static void main(String[] args) throws Exception {
        boolean ok = true;
        ok &= testDeserializedLength(10);
        ok &= testDeserializedLength(50);
        ok &= testDeserializedLength(500);
        ok &= testDeserializedLength(5000);
        if (!ok) {
            throw new AssertionError("Test failed.");
        }
    }
}