py4j.commands

Class AbstractCommand

java.lang.Object

py4j.commands.AbstractCommand

All Implemented Interfaces:

Command

Direct Known Subclasses:

ArrayCommand, AuthCommand, CallCommand, ConstructorCommand, DirCommand, ExceptionCommand, FieldCommand, HelpPageCommand, JVMViewCommand, ListCommand, MemoryCommand, ReflectionCommand, ShutdownGatewayServerCommand, StreamCommand

public abstract class AbstractCommand
extends java.lang.Object
implements Command

Abstract base class for commands. Provides useful methods allowing the parsing of command arguments.

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.String	commandName
protected Py4JServerConnection	connection
protected Gateway	gateway

Constructor Summary

Constructors

Constructor and Description
AbstractCommand()

Method Summary

Modifier and Type	Method and Description
abstract void	execute(java.lang.String commandName, java.io.BufferedReader reader, java.io.BufferedWriter writer)
protected java.util.List<java.lang.Object>	getArguments(java.io.BufferedReader reader)
java.lang.String	getCommandName()
protected java.util.List<java.lang.String>	getStringArguments(java.io.BufferedReader reader)
void	init(Gateway gateway, Py4JServerConnection connection) Called when a command instance is created and assigned to a connection.
protected ReturnObject	invokeMethod(java.lang.String methodName, java.lang.String targetObjectId, java.util.List<java.lang.Object> arguments) Convenient shortcut to invoke a method dynamically.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

gateway

protected Gateway gateway

commandName

protected java.lang.String commandName

connection

protected Py4JServerConnection connection

Constructor Detail

AbstractCommand

public AbstractCommand()

Method Detail

execute

public abstract void execute(java.lang.String commandName,
                             java.io.BufferedReader reader,
                             java.io.BufferedWriter writer)
                      throws Py4JException,
                             java.io.IOException

Specified by:

execute in interface Command

Parameters:

commandName - The command name that was extracted of the command.

reader - The reader from which to read the command parts. Each command part are expected to be on a separate line and readable through BufferedReader.readLine().

writer - The writer to which the return value should be written.

Throws:

Py4JException - If an error occurs while executing the command. All exceptions except IOException caused by the reader and the writer should be wrapper in a Py4JException instance.

java.io.IOException - If an error occurs while using the reader or the writer.

getArguments

protected java.util.List<java.lang.Object> getArguments(java.io.BufferedReader reader)
                                                 throws java.io.IOException

Parameters:

reader -

Returns:

A list of the remaining arguments (converted using Protocol.getObject) in the reader. Consumes the end of command part.

Throws:

java.io.IOException

getCommandName

public java.lang.String getCommandName()

Specified by:

getCommandName in interface Command

getStringArguments

protected java.util.List<java.lang.String> getStringArguments(java.io.BufferedReader reader)
                                                       throws java.io.IOException

Parameters:

reader -

Returns:

A list of the remaining arguments (as strings) in the reader. Consumes the end of command part.

Throws:

java.io.IOException

init

public void init(Gateway gateway,
                 Py4JServerConnection connection)

Description copied from interface: Command

Called when a command instance is created and assigned to a connection.

Specified by:

init in interface Command

connection - the Py4JServerConnection this socket is assigned to

invokeMethod

protected ReturnObject invokeMethod(java.lang.String methodName,
                                    java.lang.String targetObjectId,
                                    java.util.List<java.lang.Object> arguments)

Convenient shortcut to invoke a method dynamically.

Parameters:

methodName -

targetObjectId -

arguments -

Returns: