Command (py4j-java 0.10.9.7 API)

All Known Implementing Classes:

AbstractCommand, ArrayCommand, AuthCommand, CallCommand, ConstructorCommand, DirCommand, ExceptionCommand, FieldCommand, HelpPageCommand, JVMViewCommand, ListCommand, MemoryCommand, ReflectionCommand, ShutdownGatewayServerCommand, StreamCommand
```
public interface Command
```
This interface must be implemented by all commands.

Typically, each command will define a public constant field that contains the command name, i.e., a String that uniquely identifies the command.

The command name can be a String of any length, but it must not contain an end of line character and it cannot be the End of Command character, Protocol.END.

There is a command instance per GatewayConnection: this ensures that each command instance is accessed by only one thread/connection at a time.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`execute(java.lang.String commandName, java.io.BufferedReader reader, java.io.BufferedWriter writer)`
`java.lang.String`	`getCommandName()`
`void`	`init(Gateway gateway, Py4JServerConnection connection)`	Called when a command instance is created and assigned to a connection.

- Method Detail
  - execute
```
void execute(java.lang.String commandName,
             java.io.BufferedReader reader,
             java.io.BufferedWriter writer)
      throws Py4JException,
             java.io.IOException
```
    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.
  - getCommandName
```
java.lang.String getCommandName()
```
  - init
```
void init(Gateway gateway,
          Py4JServerConnection connection)
```
    Called when a command instance is created and assigned to a connection.
    
    Parameters:
    
    gateway -
    
    connection - the Py4JServerConnection this socket is assigned to