Is it possible to implements ESL Interface in Java?

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#1

Hello, I wanted to use ESL Interface for stronger binding and I have my algorithm implemented in java. Is it possible to declare it as implementation of ESL interface?

#2

Hello,
You cannot declare it implemented, but it still can be used as an implementation with some limitations.
You can call your java implementation from ESL in this way:

CALLJ [E.Server] I.Server^service ON SELF.EVH

Method public void service() { } will be called. No declaration of implementation of interface is needed, but:

  • If you call it from ESL, you need at least formal implementation of ESL interface in ESL part of event E.Server:
IMPLEMENTATION I.Server

IMPLEMENTATION RPC PROCEDURE I.Server^Service
; empty body
END Service
  • ESL allows to distinguish between implementation of two methods with the same name and parameters that origing from two different interfaces:
IMPLEMENTATION I.A
IMPLEMENTATION I.B

IMPLEMENTATION RPC PROCEDURE I.A^make(INT _a)
; do something
END make

IMPLEMENTATION RPC PROCEDURE I.B^make(INT _a)
; do something else
END make
  • Java supports overloading of methods based on different parameters, but if parameters are same, you can have only one implementation for both of methods, unless you implement wrapper in ESL:
IMPLEMENTATION I.A
IMPLEMENTATION I.B

IMPLEMENTATION RPC PROCEDURE I.A^make(INT _a)
  CALLJ [E.Server] I.A^make_I_A(_a) ON SELF.EVH
END make

IMPLEMENTATION RPC PROCEDURE I.B^make(INT _a)
  CALLJ [E.Server] I.A^make_I_B(_a) ON SELF.EVH
END make
  • Note the fact that ESL in case insensitive but java is case sensitive. Therefore you can legally call from java both methods: make(_a) ad Make(_a) and the same ESL method would be called but they will end up as calls of different java methods.