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Java example source code file (DefaultCaching.java)

This example Java source code file (DefaultCaching.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

defaultcaching, inetaddress, interruptedexception, net, network, runtimeexception, security, string, unknownhostexception

The DefaultCaching.java Java example source code

/*
 * Copyright (c) 2006, 2011, 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 6442088
 * @summary Change default DNS caching behavior for code not running under
 *          security manager.
 * @compile -XDignore.symbol.file=true SimpleNameService.java
 *                                     SimpleNameServiceDescriptor.java
 * @run main/othervm/timeout=200 -Dsun.net.inetaddr.ttl=20 -Dsun.net.spi.nameservice.provider.1=simple,sun DefaultCaching
 */
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.Security;

public class DefaultCaching {

    public static void main(String args[]) throws Exception {

        // name service needs to resolve this.
        SimpleNameService.put("theclub", "129.156.220.219");

        test ("theclub", "129.156.220.219", true);      // lk: 1
        test ("luster", "1.16.20.2", false);            // lk: 2

        // name service now needs to know about luster
        SimpleNameService.put("luster", "10.5.18.21");

        test ("luster", "1.16.20.2", false);            // lk: 2
        sleep (10+1);
        test("luster", "10.5.18.21", true, 3);          // lk: 3
        sleep (5);

        SimpleNameService.put("foo", "10.5.18.22");
        SimpleNameService.put("theclub", "129.156.220.1");

        test ("theclub", "129.156.220.219", true, 3);
        test ("luster", "10.5.18.21", true, 3);
        test ("bar", "10.5.18.22", false, 4);
        test ("foo", "10.5.18.22", true, 5);

        // now delay to see if theclub has expired
        sleep (5);

        test ("foo", "10.5.18.22", true, 5);
        test ("theclub", "129.156.220.1", true, 6);

        sleep (11);
        // now see if luster has expired
        test ("luster", "10.5.18.21", true, 7);
        test ("theclub", "129.156.220.1", true, 7);

        // now delay to see if 3rd has expired
        sleep (10+6);

        test ("theclub", "129.156.220.1", true, 8);
        test ("luster", "10.5.18.21", true, 8);
        test ("foo", "10.5.18.22", true, 9);
    }

    /* throws RuntimeException if it fails */

    static void test (String host, String address,
                        boolean shouldSucceed, int count) {
        test (host, address, shouldSucceed);
        int got = SimpleNameService.lookupCalls();
        if (got != count) {
            throw new RuntimeException ("lookups exp/got: " + count+"/"+got);
        }
    }

    static void sleep (int seconds) {
        try {
            Thread.sleep (seconds * 1000);
        } catch (InterruptedException e) {}
    }

    static void test (String host, String address, boolean shouldSucceed) {
        InetAddress addr = null;
        try {
            addr = InetAddress.getByName (host);
            if (!shouldSucceed) {
                throw new RuntimeException (host+":"+address+": should fail");

            }
            if (!address.equals(addr.getHostAddress())) {
                throw new RuntimeException(host+":"+address+": compare failed");
            }
        } catch (UnknownHostException e) {
            if (shouldSucceed) {
                throw new RuntimeException(host+":"+address+": should succeed");
            }
        }
    }

}

Other Java examples (source code examples)

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