vincent4vx / SingleInstance

 * This file is part of SingleInstance.

 *

 * SingleInstance is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * SingleInstance 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 Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with SingleInstance.  If not, see <https://www.gnu.org/licenses/>.

 *

 * Copyright (c) 2020 Vincent Quatrevieux

 */

package fr.quatrevieux.singleinstance.ipc;

import java.io.Closeable;

import java.io.IOException;

import java.io.OutputStream;

import java.net.Socket;

/**

 * IPC client for sending actions to the distant instance

 *

 * Usage:

 * <pre>{@code

 *     try (InstanceClient client = new InstanceClient(1234)) {

 *         client.send("Hello", "my payload".getBytes());

 *     }

 * }</pre>

 */

final public class InstanceClient implements Closeable, MessageSender {

    final private int port;

    private Socket socket;

    private OutputStream output;

    /**

     * @param port The listening port

     */

    /**

     * Open the client

     * Note: this method is implicitly called on {@link InstanceClient#send(Message)}

     *

     * @throws IOException When cannot open the socket

     */

    public void open() throws IOException {

        socket = new Socket("localhost", port);

        output = socket.getOutputStream();

    }

    @Override

    public void send(Message message) throws IOException {

        if (socket == null || socket.isClosed()) {

            open();

        }

        output.write(ProtocolParser.toBytes(message));

    }

    @Override

    public void close() throws IOException {

        if (socket != null) {

            output.close();

            output = null;

            socket.close();

            socket = null;

        }

    }

}