Package py4j

Class GatewayServer

  • All Implemented Interfaces:
    java.lang.Runnable, GatewayServerListener, Py4JJavaServer
    Direct Known Subclasses:
    JavaServer
    public class GatewayServer
extends DefaultGatewayServerListener
implements Py4JJavaServer, java.lang.Runnable

    This class enables Python programs to access a Java program. When a GatewayServer instance is started, Python programs can connect to the JVM by calling:

    gateway = JavaGateway()

    The entryPoint passed to a GatewayServer can be accessed with the entry_point member:

    gateway.entry_point

    Technically, a GatewayServer is only responsible for accepting connection. Each connection is then handled by a GatewayConnection instance and the various states (e.g., entryPoint, reference to returned objects) are managed by a Gateway instance.

    • Field Detail

      • DEFAULT_IPv6_ADDRESS

        public static final java.lang.String DEFAULT_IPv6_ADDRESS
        See Also:
        Constant Field Values

      • DEFAULT_CONNECT_TIMEOUT

        public static final int DEFAULT_CONNECT_TIMEOUT
        See Also:
        Constant Field Values

      • GATEWAY_SERVER_ID

        public static final java.lang.String GATEWAY_SERVER_ID
        See Also:
        Constant Field Values

      • PY4J_LOGGER

        public static final java.util.logging.Logger PY4J_LOGGER

      • authToken

        protected final java.lang.String authToken

    • Constructor Detail

      • GatewayServer

        public GatewayServer()

        Creates a GatewayServer instance with default port (25333), default address (127.0.0.1), and default timeout value (no timeout).

      • GatewayServer

        public GatewayServer​(java.lang.Object entryPoint)

        Creates a GatewayServer instance with default port (25333), default address (127.0.0.1), and default timeout value (no timeout).

        Parameters:
        entryPoint - The entry point of this Gateway. Can be null.

      • GatewayServer

        public GatewayServer​(java.lang.Object entryPoint,
                     int port)
        Parameters:
        entryPoint - The entry point of this Gateway. Can be null.
        port - The port the GatewayServer is listening to.

      • GatewayServer

        public GatewayServer​(java.lang.Object entryPoint,
                     int port,
                     int pythonPort,
                     java.net.InetAddress address,
                     java.net.InetAddress pythonAddress,
                     int connectTimeout,
                     int readTimeout,
                     java.util.List<java.lang.Class<? extends Command>> customCommands)
        Parameters:
        entryPoint - The entry point of this Gateway. Can be null.
        port - The port the GatewayServer is listening to.
        pythonPort - The port used by a PythonProxyHandler to connect to a Python gateway. Essentially the port used for Python callbacks.
        address - The address the GatewayServer is listening to.
        pythonAddress - The address used by a PythonProxyHandler to connect to a Python gateway.
        connectTimeout - Time in milliseconds (0 = infinite). If a GatewayServer does not receive a connection request after this time, it closes the server socket and no other connection is accepted.
        readTimeout - Time in milliseconds (0 = infinite). Once a Python program is connected, if a GatewayServer does not receive a request (e.g., a method call) after this time, the connection with the Python program is closed.
        customCommands - A list of custom Command classes to augment the Server features. These commands will be accessible from Python programs. Can be null.

      • GatewayServer

        public GatewayServer​(java.lang.Object entryPoint,
                     int port,
                     int connectTimeout,
                     int readTimeout)
        Parameters:
        entryPoint - The entry point of this Gateway. Can be null.
        port - The port the GatewayServer is listening to.
        connectTimeout - Time in milliseconds (0 = infinite). If a GatewayServer does not receive a connection request after this time, it closes the server socket and no other connection is accepted.
        readTimeout - Time in milliseconds (0 = infinite). Once a Python program is connected, if a GatewayServer does not receive a request (e.g., a method call) after this time, the connection with the Python program is closed.

      • GatewayServer

        public GatewayServer​(java.lang.Object entryPoint,
                     int port,
                     int pythonPort,
                     int connectTimeout,
                     int readTimeout,
                     java.util.List<java.lang.Class<? extends Command>> customCommands)
        Parameters:
        entryPoint - The entry point of this Gateway. Can be null.
        port - The port the GatewayServer is listening to.
        pythonPort - The port used by a PythonProxyHandler to connect to a Python gateway. Essentially the port used for Python callbacks.
        connectTimeout - Time in milliseconds (0 = infinite). If a GatewayServer does not receive a connection request after this time, it closes the server socket and no other connection is accepted.
        readTimeout - Time in milliseconds (0 = infinite). Once a Python program is connected, if a GatewayServer does not receive a request (e.g., a method call) after this time, the connection with the Python program is closed.
        customCommands - A list of custom Command classes to augment the Server features. These commands will be accessible from Python programs. Can be null.

      • GatewayServer

        public GatewayServer​(java.lang.Object entryPoint,
                     int port,
                     int connectTimeout,
                     int readTimeout,
                     java.util.List<java.lang.Class<? extends Command>> customCommands,
                     Py4JPythonClient cbClient)
        Parameters:
        entryPoint - The entry point of this Gateway. Can be null.
        port - The port the GatewayServer is listening to.
        connectTimeout - Time in milliseconds (0 = infinite). If a GatewayServer does not receive a connection request after this time, it closes the server socket and no other connection is accepted.
        readTimeout - Time in milliseconds (0 = infinite). Once a Python program is connected, if a GatewayServer does not receive a request (e.g., a method call) after this time, the connection with the Python program is closed.
        customCommands - A list of custom Command classes to augment the Server features. These commands will be accessible from Python programs. Can be null.
        cbClient - An instance of a callback client.

      • GatewayServer

        public GatewayServer​(java.lang.Object entryPoint,
                     int port,
                     java.net.InetAddress address,
                     int connectTimeout,
                     int readTimeout,
                     java.util.List<java.lang.Class<? extends Command>> customCommands,
                     Py4JPythonClient cbClient)
        Parameters:
        entryPoint - The entry point of this Gateway. Can be null.
        port - The port the GatewayServer is listening to.
        address - The address the GatewayServer is listening to.
        connectTimeout - Time in milliseconds (0 = infinite). If a GatewayServer does not receive a connection request after this time, it closes the server socket and no other connection is accepted.
        readTimeout - Time in milliseconds (0 = infinite). Once a Python program is connected, if a GatewayServer does not receive a request (e.g., a method call) after this time, the connection with the Python program is closed.
        customCommands - A list of custom Command classes to augment the Server features. These commands will be accessible from Python programs. Can be null.
        cbClient - An instance of a callback client.

      • GatewayServer

        public GatewayServer​(java.lang.Object entryPoint,
                     int port,
                     java.net.InetAddress address,
                     int connectTimeout,
                     int readTimeout,
                     java.util.List<java.lang.Class<? extends Command>> customCommands,
                     Py4JPythonClient cbClient,
                     javax.net.ServerSocketFactory sSocketFactory)
        Parameters:
        entryPoint - The entry point of this Gateway. Can be null.
        port - The port the GatewayServer is listening to.
        address - The address the GatewayServer is listening to.
        connectTimeout - Time in milliseconds (0 = infinite). If a GatewayServer does not receive a connection request after this time, it closes the server socket and no other connection is accepted.
        readTimeout - Time in milliseconds (0 = infinite). Once a Python program is connected, if a GatewayServer does not receive a request (e.g., a method call) after this time, the connection with the Python program is closed.
        customCommands - A list of custom Command classes to augment the Server features. These commands will be accessible from Python programs. Can be null.
        sSocketFactory - A factory that creates the server sockets that we listen on.

      • GatewayServer

        public GatewayServer​(Gateway gateway,
                     int port,
                     java.net.InetAddress address,
                     int connectTimeout,
                     int readTimeout,
                     java.util.List<java.lang.Class<? extends Command>> customCommands,
                     javax.net.ServerSocketFactory sSocketFactory)
        Parameters:
        gateway - gateway instance (or subclass). Must not be null.
        port - the host port to usu
        address - the host address to use
        connectTimeout - the connect timeout (ms)
        readTimeout - the read timeout (ms)
        customCommands - any customCommands to use. May be null
        sSocketFactory - socketFactory to use. Must not be null

    • Method Detail

      • turnAllLoggingOn

        public static void turnAllLoggingOn()

        Utility method to turn logging on. Logging is turned off by default. All log messages will be logged.

      • turnLoggingOff

        public static void turnLoggingOff()

        Utility method to turn logging off. Logging is turned off by default.

      • turnLoggingOn

        public static void turnLoggingOn()

        Utility method to turn logging on. Logging is turned off by default. Log messages up to INFO level will be logged.

      • defaultAddress

        public static java.net.InetAddress defaultAddress()

      • defaultIPv6Address

        public static java.net.InetAddress defaultIPv6Address()

      • resetCallbackClient

        public void resetCallbackClient​(java.net.InetAddress pythonAddress,
                                int pythonPort)

        Replace the callback client with the new one which connects to the given address and port. This method is useful if for some reason your CallbackServer changes its address or you come to know of the address after Gateway has already instantiated.

        This method is not thread-safe! Make sure that only one thread calls this method.

        Parameters:
        pythonAddress - The address used by a PythonProxyHandler to connect to a Python gateway.
        pythonPort - The port used by a PythonProxyHandler to connect to a Python gateway. Essentially the port used for Python callbacks.

      • createConnection

        protected Py4JServerConnection createConnection​(Gateway gateway,
                                                java.net.Socket socket)
                                         throws java.io.IOException

        Creates a server connection from a Python call to the Java side.

        Parameters:
        gateway -
        socket -
        Returns:
        Throws:
        java.io.IOException

      • fireConnectionError

        protected void fireConnectionError​(java.lang.Exception e)

      • fireConnectionStarted

        protected void fireConnectionStarted​(Py4JServerConnection gatewayConnection)

      • fireServerError

        protected void fireServerError​(java.lang.Exception e)

      • fireServerPostShutdown

        protected void fireServerPostShutdown()

      • fireServerPreShutdown

        protected void fireServerPreShutdown()

      • fireServerStarted

        protected void fireServerStarted()

      • fireServerStopped

        protected void fireServerStopped()

      • getConnectTimeout

        public int getConnectTimeout()

      • getListeningPort

        public int getListeningPort()
        Specified by:
        getListeningPort in interface Py4JJavaServer
        Returns:
        The port the server socket is listening on. It will be different than the specified port if the socket is listening on an ephemeral port (specified port = 0). Returns -1 if the server socket is not listening on anything.

      • getPort

        public int getPort()
        Specified by:
        getPort in interface Py4JJavaServer
        Returns:
        The port specified when the gateway server is initialized. This is the port that is passed to the server socket.

      • getReadTimeout

        public int getReadTimeout()

      • processSocket

        protected void processSocket​(java.net.Socket socket)

      • run

        public void run()
        Specified by:
        run in interface java.lang.Runnable

      • shutdown

        public void shutdown​(boolean shutdownCallbackClient)

        Stops accepting connections, closes all current connections, and calls Gateway.shutdown()

        Specified by:
        shutdown in interface Py4JJavaServer
        Parameters:
        shutdownCallbackClient - If True, shuts down the CallbackClient instance.

      • start

        public void start()

        Starts to accept connections in a second thread (non-blocking call).

        Specified by:
        start in interface Py4JJavaServer

      • start

        public void start​(boolean fork)

        Starts to accept connections.

        Specified by:
        start in interface Py4JJavaServer
        Parameters:
        fork - If true, the GatewayServer accepts connection in another thread and this call is non-blocking. If False, the GatewayServer accepts connection in this thread and the call is blocking (until the Gateway is shutdown by another thread).
        Throws:
        Py4JNetworkException - If the server socket cannot start.

      • getPythonServerEntryPoint

        public java.lang.Object getPythonServerEntryPoint​(java.lang.Class[] interfacesToImplement)

        Gets a reference to the entry point on the Python side. This is often necessary if Java is driving the communication because Java cannot call static methods, initialize Python objects or load Python modules yet.

        Parameters:
        interfacesToImplement -
        Returns:

      • main

        public static void main​(java.lang.String[] args)

        Main method to start a local GatewayServer on either a given port or the default one. The listening port is printed to stdout so that clients can start servers on ephemeral ports.

        If authentication is enabled, the server will create an auth secret with 256 bits of entropy and print it to stdout after the server port. Clients should then provide this secret when connecting to the server. Note that no second line of output is printed if authentication is not enabled.

      • getCustomCommands

        public java.util.List<java.lang.Class<? extends Command>> getCustomCommands()
        Returns:
        An unmodifiable list of custom commands