Java example source code file (Chars.java)

This example Java source code file (Chars.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arraylist, charbuffer, chars, dataprovider, list, nio, object, random, size, test, util

The Chars.java Java example source code

/*
 * Copyright (c) 2013, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/**
 * @test
 * @bug 8014854
 * @summary Exercises CharBuffer#chars on each of the CharBuffer types
 * @run testng Chars
 */

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;

import static org.testng.Assert.assertEquals;

public class Chars {

    static final Random RAND = new Random();

    static final int SIZE = 128 + RAND.nextInt(1024);

    /**
     * Randomize the char buffer's position and limit.
     */
    static CharBuffer randomizeRange(CharBuffer cb) {
        int mid = cb.capacity() >>> 1;
        int start = RAND.nextInt(mid);
        int end = mid + RAND.nextInt(mid);
        cb.position(start);
        cb.limit(end);
        return cb;
    }

    /**
     * Randomize the char buffer's contents, position and limit.
     */
    static CharBuffer randomize(CharBuffer cb) {
        while (cb.hasRemaining()) {
            cb.put((char)RAND.nextInt());
        }
        return randomizeRange(cb);
    }

    /**
     * Sums the remaining chars in the char buffer.
     */
    static int intSum(CharBuffer cb) {
        int sum = 0;
        cb.mark();
        while (cb.hasRemaining()) {
            sum += cb.get();
        }
        cb.reset();
        return sum;
    }

    /**
     * Creates char buffers to test, adding them to the given list.
     */
    static void addCases(CharBuffer cb, List<CharBuffer> buffers) {
        randomize(cb);
        buffers.add(cb);

        buffers.add(cb.slice());
        buffers.add(cb.duplicate());
        buffers.add(cb.asReadOnlyBuffer());

        buffers.add(randomizeRange(cb.slice()));
        buffers.add(randomizeRange(cb.duplicate()));
        buffers.add(randomizeRange(cb.asReadOnlyBuffer()));
    }

    @DataProvider(name = "charbuffers")
    public Object[][] createCharBuffers() {
        List<CharBuffer> buffers = new ArrayList<>();

        // heap
        addCases(CharBuffer.allocate(SIZE), buffers);
        addCases(CharBuffer.wrap(new char[SIZE]), buffers);
        addCases(ByteBuffer.allocate(SIZE*2).order(ByteOrder.BIG_ENDIAN).asCharBuffer(),
                 buffers);
        addCases(ByteBuffer.allocate(SIZE*2).order(ByteOrder.LITTLE_ENDIAN).asCharBuffer(),
                 buffers);

        // direct
        addCases(ByteBuffer.allocateDirect(SIZE*2).order(ByteOrder.BIG_ENDIAN).asCharBuffer(),
                 buffers);
        addCases(ByteBuffer.allocateDirect(SIZE*2).order(ByteOrder.LITTLE_ENDIAN).asCharBuffer(),
                 buffers);

        // read-only buffer backed by a CharSequence
        buffers.add(CharBuffer.wrap(randomize(CharBuffer.allocate(SIZE))));

        Object[][] params = new Object[buffers.size()][];
        for (int i = 0; i < buffers.size(); i++) {
            CharBuffer cb = buffers.get(i);
            params[i] = new Object[] { cb.getClass().getName(), cb };
        }

        return params;
    }

    @Test(dataProvider = "charbuffers")
    public void testChars(String type, CharBuffer cb) {
        System.out.format("%s position=%d, limit=%d%n", type, cb.position(), cb.limit());
        int expected = intSum(cb);
        assertEquals(cb.chars().sum(), expected);
        assertEquals(cb.chars().parallel().sum(), expected);
    }
}