org.rhq.bindings.engine
Interface ScriptEngineInitializer

All Known Implementing Classes:

JsEngineInitializer

public interface ScriptEngineInitializer

Is able to instantiate a script engine and import packages into the context of the engine.

Author:

Lukas Krejci

Method Summary

String	extractUserFriendlyErrorMessage(ScriptException e) At least the Rhino script engine for java script generates exceptions whose error messages contain just "too much" information to be easily decipherable by the end users.
Set<String>	generateIndirectionMethods(String boundObjectName, Set<Method> overloadedMethods) This function returns a definition string in the script engine's language that provides an indirection to calling the method on the bound object.
boolean	implementsLanguage(String language)
ScriptEngine	instantiate(Set<String> packages)

Method Detail

implementsLanguage

boolean implementsLanguage(String language)

instantiate

ScriptEngine instantiate(Set<String> packages)
                         throws ScriptException

Throws:

ScriptException

generateIndirectionMethods

Set<String> generateIndirectionMethods(String boundObjectName,
                                       Set<Method> overloadedMethods)

This function returns a definition string in the script engine's language that provides an indirection to calling the method on the bound object. for example for parameters:

• boundObjectName = foo
• method = <int bar(int)>

The method would generate this javascript:
function bar(arg) { return foo.bar(arg); }

This method gets passed all the overloaded versions of a method on the object (i.e. all the methods with the same name) and is free to return any number of functions that will map all the possible overloaded versions.

This is because different scripting languages have different support for function overloading and different ways of handling varying number of arguments of a function.

Parameters:

boundObjectName -

overloadedMethods -

Returns:

a set of strings with top-level function definitions in the scripting language

extractUserFriendlyErrorMessage

String extractUserFriendlyErrorMessage(ScriptException e)

At least the Rhino script engine for java script generates exceptions whose error messages contain just "too much" information to be easily decipherable by the end users.

This method extracts messages from the exception such that they are presentable to the end user.

The returned string should only contain the error message. The filename, line and column information should be stripped from it if at all possible.

Parameters:

e -

Returns: