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Java example source code file (DnsServerAddressesTest.java)

This example Java source code file (DnsServerAddressesTest.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

addr1, addr2, addr3, boolean, dnsserveraddresses, dnsserveraddressestest, dnsserveraddressstream, identityhashmap, inetsocketaddress, net, network, set, test, util

The DnsServerAddressesTest.java Java example source code

/*
 * Copyright 2014 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.resolver.dns;

import io.netty.util.NetUtil;
import org.junit.Test;

import java.net.InetSocketAddress;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Set;

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

public class DnsServerAddressesTest {

    private static final InetSocketAddress ADDR1 = new InetSocketAddress(NetUtil.LOCALHOST, 1);
    private static final InetSocketAddress ADDR2 = new InetSocketAddress(NetUtil.LOCALHOST, 2);
    private static final InetSocketAddress ADDR3 = new InetSocketAddress(NetUtil.LOCALHOST, 3);

    @Test
    public void testDefaultAddresses() {
        assertThat(DnsServerAddresses.defaultAddressList().size(), is(greaterThan(0)));
    }

    @Test
    public void testSequential() {
        DnsServerAddresses seq = DnsServerAddresses.sequential(ADDR1, ADDR2, ADDR3);
        assertThat(seq.stream(), is(not(sameInstance(seq.stream()))));

        for (int j = 0; j < 2; j ++) {
            DnsServerAddressStream i = seq.stream();
            assertNext(i, ADDR1);
            assertNext(i, ADDR2);
            assertNext(i, ADDR3);
            assertNext(i, ADDR1);
            assertNext(i, ADDR2);
            assertNext(i, ADDR3);
        }
    }

    @Test
    public void testRotational() {
        DnsServerAddresses seq = DnsServerAddresses.rotational(ADDR1, ADDR2, ADDR3);

        DnsServerAddressStream i = seq.stream();
        assertNext(i, ADDR1);
        assertNext(i, ADDR2);
        assertNext(i, ADDR3);
        assertNext(i, ADDR1);
        assertNext(i, ADDR2);
        assertNext(i, ADDR3);

        i = seq.stream();
        assertNext(i, ADDR2);
        assertNext(i, ADDR3);
        assertNext(i, ADDR1);
        assertNext(i, ADDR2);
        assertNext(i, ADDR3);
        assertNext(i, ADDR1);

        i = seq.stream();
        assertNext(i, ADDR3);
        assertNext(i, ADDR1);
        assertNext(i, ADDR2);
        assertNext(i, ADDR3);
        assertNext(i, ADDR1);
        assertNext(i, ADDR2);

        i = seq.stream();
        assertNext(i, ADDR1);
        assertNext(i, ADDR2);
        assertNext(i, ADDR3);
        assertNext(i, ADDR1);
        assertNext(i, ADDR2);
        assertNext(i, ADDR3);
    }

    @Test
    public void testShuffled() {
        DnsServerAddresses seq = DnsServerAddresses.shuffled(ADDR1, ADDR2, ADDR3);

        // Ensure that all three addresses are returned by the iterator.
        // In theory, this test can fail at extremely low chance, but we don't really care.
        Set<InetSocketAddress> set = Collections.newSetFromMap(new IdentityHashMap());
        DnsServerAddressStream i = seq.stream();
        for (int j = 0; j < 1048576; j ++) {
            set.add(i.next());
        }

        assertThat(set.size(), is(3));
        assertThat(seq.stream(), is(not(sameInstance(seq.stream()))));
    }

    @Test
    public void testSingleton() {
        DnsServerAddresses seq = DnsServerAddresses.singleton(ADDR1);

        // Should return the same iterator instance for least possible footprint.
        assertThat(seq.stream(), is(sameInstance(seq.stream())));

        DnsServerAddressStream i = seq.stream();
        assertNext(i, ADDR1);
        assertNext(i, ADDR1);
        assertNext(i, ADDR1);
    }

    private static void assertNext(DnsServerAddressStream i, InetSocketAddress addr) {
        assertThat(i.next(), is(sameInstance(addr)));
    }
}

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