Package py4j

Class GatewayServer

All Implemented Interfaces:
Runnable, GatewayServerListener, Py4JJavaServer
Direct Known Subclasses:
JavaServer

public class GatewayServer extends DefaultGatewayServerListener implements Py4JJavaServer, 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.

Author:
Barthelemy Dagenais
  • Field Details

  • Constructor Details

    • 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(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(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(Object entryPoint, int port, int pythonPort, InetAddress address, InetAddress pythonAddress, int connectTimeout, int readTimeout, List<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(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(Object entryPoint, int port, int pythonPort, int connectTimeout, int readTimeout, List<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(Object entryPoint, int port, int connectTimeout, int readTimeout, List<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(Object entryPoint, int port, InetAddress address, int connectTimeout, int readTimeout, List<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(Object entryPoint, int port, InetAddress address, int connectTimeout, int readTimeout, List<Class<? extends Command>> customCommands, Py4JPythonClient cbClient, 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, InetAddress address, int connectTimeout, int readTimeout, List<Class<? extends Command>> customCommands, 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 Details

    • 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 InetAddress defaultAddress()
    • defaultIPv6Address

      public static InetAddress defaultIPv6Address()
    • resetCallbackClient

      public void resetCallbackClient(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.
    • addListener

      public void addListener(GatewayServerListener listener)
      Specified by:
      addListener in interface Py4JJavaServer
    • connectionStopped

      public void connectionStopped(Py4JServerConnection gatewayConnection)
      Specified by:
      connectionStopped in interface GatewayServerListener
      Overrides:
      connectionStopped in class DefaultGatewayServerListener
    • createConnection

      protected Py4JServerConnection createConnection(Gateway gateway, Socket socket) throws IOException

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

      Parameters:
      gateway -
      socket -
      Returns:
      Throws:
      IOException
    • fireConnectionError

      protected void fireConnectionError(Exception e)
    • fireConnectionStarted

      protected void fireConnectionStarted(Py4JServerConnection gatewayConnection)
    • fireServerError

      protected void fireServerError(Exception e)
    • fireServerPostShutdown

      protected void fireServerPostShutdown()
    • fireServerPreShutdown

      protected void fireServerPreShutdown()
    • fireServerStarted

      protected void fireServerStarted()
    • fireServerStopped

      protected void fireServerStopped()
    • getAddress

      public InetAddress getAddress()
      Specified by:
      getAddress in interface Py4JJavaServer
    • getCallbackClient

      public Py4JPythonClient getCallbackClient()
    • getConnectTimeout

      public int getConnectTimeout()
    • getGateway

      public Gateway getGateway()
      Specified by:
      getGateway in interface Py4JJavaServer
    • 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.
    • getPythonAddress

      public InetAddress getPythonAddress()
      Specified by:
      getPythonAddress in interface Py4JJavaServer
    • getPythonPort

      public int getPythonPort()
      Specified by:
      getPythonPort in interface Py4JJavaServer
    • getReadTimeout

      public int getReadTimeout()
    • processSocket

      protected void processSocket(Socket socket)
    • removeListener

      public void removeListener(GatewayServerListener listener)
      Specified by:
      removeListener in interface Py4JJavaServer
    • run

      public void run()
      Specified by:
      run in interface Runnable
    • shutdown

      public void shutdown()

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

      Specified by:
      shutdown in interface Py4JJavaServer
    • 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.
    • startSocket

      protected void startSocket() throws Py4JNetworkException

      Starts the ServerSocket.

      Throws:
      Py4JNetworkException - If the port is busy.
    • getPythonServerEntryPoint

      public Object getPythonServerEntryPoint(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(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 List<Class<? extends Command>> getCustomCommands()
      Returns:
      An unmodifiable list of custom commands
    • getListeners

      public List<GatewayServerListener> getListeners()
      Specified by:
      getListeners in interface Py4JJavaServer
      Returns:
      An unmodifiable list of listeners