DMDirc-Client/src/main/java/com/dmdirc/commandline/RemoteServer.java

/*
 * Copyright (c) 2006-2017 DMDirc Developers
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
 * OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package com.dmdirc.commandline;

import com.dmdirc.interfaces.ConnectionManager;

import java.net.URI;
import java.rmi.NotBoundException;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;
import java.util.List;

import javax.inject.Provider;

/**
 * An RMI server that allows other clients to interact with DMDirc.
 */
public class RemoteServer implements RemoteInterface {

    /** The minimum port to use for RMI binding. */
    private static final int MINPORT = 3634;
    /** The maximum port to use for RMI binding. */
    private static final int MAXPORT = MINPORT + 5;
    /** Provider for the server manager to use to connect. */
    private final Provider<ConnectionManager> serverManager;

    /**
     * Crate a new RemoteServer.
     *
     * @param serverManager Provider of a server manager to use to connect.
     */
    public RemoteServer(final Provider<ConnectionManager> serverManager) {
        this.serverManager = serverManager;
    }

    @Override
    public void connect(final List<URI> addresses) throws RemoteException {
        for (URI address : addresses) {
            serverManager.get().connectToAddress(address);
        }
    }

    /**
     * Binds to the RMI registry so that other clients may find this remote server.
     */
    public void bind() {
        final RemoteInterface stub;

        try {
            stub = (RemoteInterface) UnicastRemoteObject.exportObject(this, 0);
        } catch (RemoteException ex) {
            System.err.println("Unable to export the remote interface");
            ex.printStackTrace();
            return;
        }

        for (int port = MINPORT; port < MAXPORT; port++) {
            try {
                final Registry registry = LocateRegistry.createRegistry(port);
                registry.rebind("DMDirc", stub);
                return;
            } catch (RemoteException ex) {
            }
        }
    }

    /**
     * Retrieves a reference to an existing RemoteServer, if there is one. Note that this must be
     * called before bind(), unless you want a reference to our own client for some reason.
     *
     * @return The RemoteServer instance, or null if none was available
     */
    public static RemoteInterface getServer() {
        for (int port = MINPORT; port < MAXPORT; port++) {
            try {
                final Registry registry = LocateRegistry.getRegistry("localhost", port);
                final RemoteInterface iface = (RemoteInterface) registry.lookup("DMDirc");

                if (iface != null) {
                    return iface;
                }
            } catch (RemoteException | NotBoundException ex) {
            }
        }

        // No RMI server found
        return null;
    }

}