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Java example source code file (ByteBufDerivationTest.java)

This example Java source code file (ByteBufDerivationTest.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

bytebuf, bytebufderivationtest, error, exception, nio, random, swappedbytebuf, test, util

The ByteBufDerivationTest.java Java example source code

/*
 * Copyright 2013 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package io.netty.buffer;

import org.junit.Test;

import java.nio.ByteOrder;
import java.util.Random;

import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;

/**
 * Tests wrapping a wrapped buffer does not go way too deep chaining.
 */
public class ByteBufDerivationTest {

    @Test
    public void testSlice() throws Exception {
        ByteBuf buf = Unpooled.buffer(8).setIndex(1, 7);
        ByteBuf slice = buf.slice(1, 7);

        assertThat(slice, instanceOf(SlicedByteBuf.class));
        assertThat(slice.unwrap(), sameInstance(buf));
        assertThat(slice.readerIndex(), is(0));
        assertThat(slice.writerIndex(), is(7));
        assertThat(slice.capacity(), is(7));
        assertThat(slice.maxCapacity(), is(7));

        slice.setIndex(1, 6);
        assertThat(buf.readerIndex(), is(1));
        assertThat(buf.writerIndex(), is(7));
    }

    @Test
    public void testSliceOfSlice() throws Exception {
        ByteBuf buf = Unpooled.buffer(8);
        ByteBuf slice = buf.slice(1, 7);
        ByteBuf slice2 = slice.slice(0, 6);

        assertThat(slice2, not(sameInstance(slice)));
        assertThat(slice2, instanceOf(SlicedByteBuf.class));
        assertThat(slice2.unwrap(), sameInstance(buf));
        assertThat(slice2.writerIndex(), is(6));
        assertThat(slice2.capacity(), is(6));
    }

    @Test
    public void testDuplicate() throws Exception {
        ByteBuf buf = Unpooled.buffer(8).setIndex(1, 7);
        ByteBuf dup = buf.duplicate();

        assertThat(dup, instanceOf(DuplicatedByteBuf.class));
        assertThat(dup.unwrap(), sameInstance(buf));
        assertThat(dup.readerIndex(), is(buf.readerIndex()));
        assertThat(dup.writerIndex(), is(buf.writerIndex()));
        assertThat(dup.capacity(), is(buf.capacity()));
        assertThat(dup.maxCapacity(), is(buf.maxCapacity()));

        dup.setIndex(2, 6);
        assertThat(buf.readerIndex(), is(1));
        assertThat(buf.writerIndex(), is(7));
    }

    @Test
    public void testDuplicateOfDuplicate() throws Exception {
        ByteBuf buf = Unpooled.buffer(8).setIndex(1, 7);
        ByteBuf dup = buf.duplicate().setIndex(2, 6);
        ByteBuf dup2 = dup.duplicate();

        assertThat(dup2, not(sameInstance(dup)));
        assertThat(dup2, instanceOf(DuplicatedByteBuf.class));
        assertThat(dup2.unwrap(), sameInstance(buf));
        assertThat(dup2.readerIndex(), is(dup.readerIndex()));
        assertThat(dup2.writerIndex(), is(dup.writerIndex()));
        assertThat(dup2.capacity(), is(dup.capacity()));
        assertThat(dup2.maxCapacity(), is(dup.maxCapacity()));
    }

    @Test
    public void testReadOnly() throws Exception {
        ByteBuf buf = Unpooled.buffer(8).setIndex(1, 7);
        ByteBuf ro = Unpooled.unmodifiableBuffer(buf);

        assertThat(ro, instanceOf(ReadOnlyByteBuf.class));
        assertThat(ro.unwrap(), sameInstance(buf));
        assertThat(ro.readerIndex(), is(buf.readerIndex()));
        assertThat(ro.writerIndex(), is(buf.writerIndex()));
        assertThat(ro.capacity(), is(buf.capacity()));
        assertThat(ro.maxCapacity(), is(buf.maxCapacity()));

        ro.setIndex(2, 6);
        assertThat(buf.readerIndex(), is(1));
    }

    @Test
    public void testReadOnlyOfReadOnly() throws Exception {
        ByteBuf buf = Unpooled.buffer(8).setIndex(1, 7);
        ByteBuf ro = Unpooled.unmodifiableBuffer(buf).setIndex(2, 6);
        ByteBuf ro2 = Unpooled.unmodifiableBuffer(ro);

        assertThat(ro2, not(sameInstance(ro)));
        assertThat(ro2, instanceOf(ReadOnlyByteBuf.class));
        assertThat(ro2.unwrap(), sameInstance(buf));
        assertThat(ro2.readerIndex(), is(ro.readerIndex()));
        assertThat(ro2.writerIndex(), is(ro.writerIndex()));
        assertThat(ro2.capacity(), is(ro.capacity()));
        assertThat(ro2.maxCapacity(), is(ro.maxCapacity()));
    }

    @Test
    public void testReadOnlyOfDuplicate() throws Exception {
        ByteBuf buf = Unpooled.buffer(8).setIndex(1, 7);
        ByteBuf dup = buf.duplicate().setIndex(2, 6);
        ByteBuf ro = Unpooled.unmodifiableBuffer(dup);

        assertThat(ro, instanceOf(ReadOnlyByteBuf.class));
        assertThat(ro.unwrap(), sameInstance(buf));
        assertThat(ro.readerIndex(), is(dup.readerIndex()));
        assertThat(ro.writerIndex(), is(dup.writerIndex()));
        assertThat(ro.capacity(), is(dup.capacity()));
        assertThat(ro.maxCapacity(), is(dup.maxCapacity()));
    }

    @Test
    public void testDuplicateOfReadOnly() throws Exception {
        ByteBuf buf = Unpooled.buffer(8).setIndex(1, 7);
        ByteBuf ro = Unpooled.unmodifiableBuffer(buf).setIndex(2, 6);
        ByteBuf dup = ro.duplicate();

        assertThat(dup, instanceOf(ReadOnlyByteBuf.class));
        assertThat(dup.unwrap(), sameInstance(buf));
        assertThat(dup.readerIndex(), is(ro.readerIndex()));
        assertThat(dup.writerIndex(), is(ro.writerIndex()));
        assertThat(dup.capacity(), is(ro.capacity()));
        assertThat(dup.maxCapacity(), is(ro.maxCapacity()));
    }

    @Test
    public void testSwap() throws Exception {
        ByteBuf buf = Unpooled.buffer(8).setIndex(1, 7);
        ByteBuf swapped = buf.order(ByteOrder.LITTLE_ENDIAN);

        assertThat(swapped, instanceOf(SwappedByteBuf.class));
        assertThat(swapped.unwrap(), is((ByteBuf) null));
        assertThat(swapped.order(ByteOrder.LITTLE_ENDIAN), sameInstance(swapped));
        assertThat(swapped.order(ByteOrder.BIG_ENDIAN), sameInstance(buf));

        buf.setIndex(2, 6);
        assertThat(swapped.readerIndex(), is(2));
        assertThat(swapped.writerIndex(), is(6));
    }

    @Test
    public void testMixture() throws Exception {
        ByteBuf buf = Unpooled.buffer(10000);
        ByteBuf derived = buf;
        Random rnd = new Random();
        for (int i = 0; i < buf.capacity(); i ++) {
            ByteBuf newDerived;
            switch (rnd.nextInt(4)) {
            case 0:
                newDerived = derived.slice(1, derived.capacity() - 1);
                break;
            case 1:
                newDerived = derived.duplicate();
                break;
            case 2:
                newDerived = derived.order(
                        derived.order() == ByteOrder.BIG_ENDIAN ? ByteOrder.LITTLE_ENDIAN : ByteOrder.BIG_ENDIAN);
                break;
            case 3:
                newDerived = Unpooled.unmodifiableBuffer(derived);
                break;
            default:
                throw new Error();
            }

            assertThat("nest level of " + newDerived, nestLevel(newDerived), is(lessThanOrEqualTo(3)));
            assertThat(
                    "nest level of " + newDerived.order(ByteOrder.BIG_ENDIAN),
                    nestLevel(newDerived.order(ByteOrder.BIG_ENDIAN)), is(lessThanOrEqualTo(2)));

            derived = newDerived;
        }
    }

    private static int nestLevel(ByteBuf buf) {
        int depth = 0;
        for (ByteBuf b = buf.order(ByteOrder.BIG_ENDIAN);;) {
            if (b.unwrap() == null && !(b instanceof SwappedByteBuf)) {
                break;
            }
            depth ++;
            if (b instanceof SwappedByteBuf) {
                b = b.order(ByteOrder.BIG_ENDIAN);
            } else {
                b = b.unwrap();
            }
        }
        return depth;
    }
}

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