DefaultCaching.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.
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 * version 2 for more details (a copy is included in the LICENSE file that
 * 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 6442088
 * @summary Change default DNS caching behavior for code not running under
 *          security manager.
 * @run main/othervm/timeout=200 -Djdk.net.hosts.file=DefaultCachingHosts
 *      -Dsun.net.inetaddr.ttl=20  DefaultCaching
 */
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.BufferedWriter;

public class DefaultCaching {

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

        String hostsFileName = System.getProperty("jdk.net.hosts.file");
        addMappingToHostsFile("theclub", "129.156.220.219", hostsFileName, false);

        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
        addMappingToHostsFile("luster", "10.5.18.21", hostsFileName, true);

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

        // new mapping for theclub and rewrite existing foo and luster mappings
        addMappingToHostsFile("theclub", "129.156.220.1", hostsFileName, false);
        addMappingToHostsFile("foo", "10.5.18.22", hostsFileName, true);
        addMappingToHostsFile("luster", "10.5.18.21", hostsFileName, true);

        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);
    }

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

    static long sleepms(long millis) throws InterruptedException {
        long start = System.nanoTime();
        long ms = millis;
        while (ms > 0) {
            assert ms < Long.MAX_VALUE/1000_000L;
            Thread.sleep(ms);
            long elapsedms = (System.nanoTime() - start)/1000_000L;
            ms = millis - elapsedms;
        }
        return millis - ms;
    }

    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 (got "
                                           + addr + ")");
            }
            if (!address.equals(addr.getHostAddress())) {
                throw new RuntimeException(host+"/"+address+": compare failed (found "
                                           + addr + ")");
            }
            System.out.println("test: " + host + "/" + address
                               + " succeeded - got " + addr);
        } catch (UnknownHostException e) {
            if (shouldSucceed) {
                throw new RuntimeException(host+":"+address+": should succeed");
            } else {
                System.out.println("test: " + host + "/" + address
                                   + " succeeded - got expected " + e);
            }
        }
    }


    private static void addMappingToHostsFile(String host,
                                              String addr,
                                              String hostsFileName,
                                              boolean append)
                                             throws Exception {
        String mapping = addr + " " + host;
        try (PrintWriter hfPWriter = new PrintWriter(new BufferedWriter(
                new FileWriter(hostsFileName, append)))) {
            hfPWriter.println(mapping);
        }
    }
}