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Java example source code file (ConstantPoolTest.java)

This example Java source code file (ConstantPoolTest.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

abstractconstant, comparator, constantpool, constantpooltest, leroy, override, redundantstringconstructorcall, set, string, suppresswarnings, test, testconstant, treeset, util

The ConstantPoolTest.java Java example source code

/*
 * Copyright 2012 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.util;

import org.junit.Test;

import java.util.Arrays;
import java.util.Comparator;
import java.util.Set;
import java.util.TreeSet;

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

public class ConstantPoolTest {

    static final class TestConstant extends AbstractConstant<TestConstant> {
        TestConstant(int id, String name) {
            super(id, name);
        }
    }

    private static final ConstantPool<TestConstant> pool = new ConstantPool() {
        @Override
        protected TestConstant newConstant(int id, String name) {
            return new TestConstant(id, name);
        }
    };

    @Test(expected = NullPointerException.class)
    public void testCannotProvideNullName() {
        pool.valueOf(null);
    }

    @Test
    @SuppressWarnings("RedundantStringConstructorCall")
    public void testUniqueness() {
        TestConstant a = pool.valueOf(new String("Leroy"));
        TestConstant b = pool.valueOf(new String("Leroy"));
        assertThat(a, is(sameInstance(b)));
    }

    @Test
    public void testIdUniqueness() {
        TestConstant one = pool.valueOf("one");
        TestConstant two = pool.valueOf("two");
        assertThat(one.id(), is(not(two.id())));
    }

    @Test
    public void testCompare() {
        TestConstant a = pool.valueOf("a_alpha");
        TestConstant b = pool.valueOf("b_beta");
        TestConstant c = pool.valueOf("c_gamma");
        TestConstant d = pool.valueOf("d_delta");
        TestConstant e = pool.valueOf("e_epsilon");

        Set<TestConstant> set = new TreeSet();
        set.add(b);
        set.add(c);
        set.add(e);
        set.add(d);
        set.add(a);

        TestConstant[] array = set.toArray(new TestConstant[5]);
        assertThat(array.length, is(5));

        // Sort by name
        Arrays.sort(array, new Comparator<TestConstant>() {
            @Override
            public int compare(TestConstant o1, TestConstant o2) {
                return o1.name().compareTo(o2.name());
            }
        });

        assertThat(array[0], is(sameInstance(a)));
        assertThat(array[1], is(sameInstance(b)));
        assertThat(array[2], is(sameInstance(c)));
        assertThat(array[3], is(sameInstance(d)));
        assertThat(array[4], is(sameInstance(e)));
    }

    @Test
    public void testComposedName() {
        TestConstant a = pool.valueOf(Object.class, "A");
        assertThat(a.name(), is("java.lang.Object#A"));
    }
}

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