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/* |
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* This file is part of SingleInstance. |
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* |
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* SingleInstance is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU Lesser General Public License as published by |
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* the Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* SingleInstance is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public License |
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* along with SingleInstance. If not, see <https://www.gnu.org/licenses/>. |
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* |
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* Copyright (c) 2020 Vincent Quatrevieux |
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*/ |
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package fr.quatrevieux.singleinstance; |
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import fr.quatrevieux.singleinstance.ipc.InstanceClient; |
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import fr.quatrevieux.singleinstance.ipc.Message; |
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import fr.quatrevieux.singleinstance.ipc.MessageSender; |
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import java.io.EOFException; |
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import java.io.IOException; |
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/** |
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* Handle information and interactions with the distant instance (i.e. the first running instance) |
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*/ |
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final public class DistantInstance implements MessageSender { |
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static private class ProcessInfo { |
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public int pid; |
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1 |
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public int port = -1; |
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public ProcessInfo(int pid) { |
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this.pid = pid; |
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} |
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public boolean hasPort() { |
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return port != -1; |
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} |
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} |
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final private LockFile lockFile; |
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private ProcessInfo info; |
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private InstanceClient client; |
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public DistantInstance(LockFile lockFile) throws IOException { |
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this.lockFile = lockFile; |
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load(); |
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} |
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/** |
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* Get the PID of the distant instance |
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* |
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* @return The PID as int |
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*/ |
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public int pid() { |
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return info.pid; |
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} |
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/** |
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* Get the opened port number |
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* |
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* @return The port number as int |
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* @throws IllegalStateException When port cannot be resolved |
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*/ |
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public int port() { |
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if (!info.hasPort()) { |
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try { |
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load(); |
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} catch (IOException e) { |
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// Ignore |
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} |
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if (!info.hasPort()) { |
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throw new IllegalStateException("The distant server is not started or cannot access to the port number"); |
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} |
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} |
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return info.port; |
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} |
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/** |
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* Get the IPC client to communicate with the distant instance |
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* Note: send methods can be used as shortcut |
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* |
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* @return The client instance |
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* @throws IllegalStateException When cannot find the port number |
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*/ |
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public InstanceClient client() { |
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if (client != null) { |
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return client; |
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} |
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return client = new InstanceClient(port()); |
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} |
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@Override |
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public void send(Message message) throws IOException { |
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client().send(message); |
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} |
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/** |
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* Load info from the lock file |
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*/ |
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private void load() throws IOException { |
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info = lockFile.read(input -> { |
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ProcessInfo processInfo = new ProcessInfo(input.readInt()); |
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try { |
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processInfo.port = input.readInt(); |
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} catch (EOFException e) { |
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processInfo.port = -1; |
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} |
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return processInfo; |
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}); |
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} |
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} |
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vincent4vx /
SingleInstance
