test/jdk/java/io/CharArrayReader/ReadCharBuffer.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
 * @test
 * @bug 4926314
 * @summary Test for CharArrayReader#read(CharBuffer).
 * @run testng ReadCharBuffer
 */

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


import java.io.CharArrayReader;
import java.io.IOException;
import java.io.Reader;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.util.Arrays;

import static org.testng.Assert.assertEquals;

public class ReadCharBuffer {

    private static final int BUFFER_SIZE = 7;

    @DataProvider(name = "buffers")
    public Object[][] createBuffers() {
        // test both on-heap and off-heap buffers as they may use different code paths
        return new Object[][]{
                new Object[]{CharBuffer.allocate(BUFFER_SIZE)},
                new Object[]{ByteBuffer.allocateDirect(BUFFER_SIZE * 2).asCharBuffer()}
        };
    }

    @Test(dataProvider = "buffers")
    public void read(CharBuffer buffer) throws IOException {
        fillBuffer(buffer);

        try (Reader reader = new CharArrayReader("ABCD".toCharArray())) {
            buffer.limit(3);
            buffer.position(1);
            assertEquals(reader.read(buffer), 2);
            assertEquals(buffer.position(), 3);
            assertEquals(buffer.limit(), 3);

            buffer.limit(7);
            buffer.position(4);
            assertEquals(reader.read(buffer), 2);
            assertEquals(buffer.position(), 6);
            assertEquals(buffer.limit(), 7);

            assertEquals(reader.read(buffer), -1);
        }

        buffer.clear();
        assertEquals(buffer.toString(), "xABxCDx");
    }

    private void fillBuffer(CharBuffer buffer) {
        char[] filler = new char[BUFFER_SIZE];
        Arrays.fill(filler, 'x');
        buffer.put(filler);
        buffer.clear();
    }

}