ThrowingNameService.java

/*
 * Copyright (c) 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.
 */

import java.net.InetAddress;
import java.net.UnknownHostException;
import sun.net.spi.nameservice.NameService;

public class ThrowingNameService implements NameService {
    static boolean firstCall = true;

    @Override
    public InetAddress[] lookupAllHostAddr(String host) throws UnknownHostException {
        if (firstCall) {
            firstCall = false;
            // throw unchecked exception first time round
            throw new IllegalStateException();
        }

        // return any valid address
        return new InetAddress[] { InetAddress.getLoopbackAddress() };
    }

    @Override
    public String getHostByAddr(byte[] addr) throws UnknownHostException {
        throw new IllegalStateException();
    }
}