org.rhq.bindings

Class ScriptEngineFactory

java.lang.Object

org.rhq.bindings.ScriptEngineFactory

public class ScriptEngineFactory
extends Object

This is RHQ specific imitation of ScriptEngineFactory. In RHQ, we provide a standard set of bound variables in the script context and also import classes from our standard packages to ease the development of the scripts.

This factory is able to instantiate a script engine and initialize it consistently so that all users of the script engine get the uniform environment to write the scripts in.

Author:

Lukas Krejci

Method Summary

Methods

Modifier and Type	Method and Description
static void	bindIndirectionMethods(ScriptEngine scriptEngine, String bindingName) Goes through the methods of the object found in the scriptEngine's ENGINE_SCOPE and for each of them generates a top-level function that is called the same name and accepts the same parameters.
static CodeCompletion	getCodeCompletion(String language)
static String	getFileExtensionForLanguage(String language)
static ScriptEngineInitializer	getInitializer(String language)
static String	getLanguageByScriptFileExtension(String fileExtension)
static ScriptEngine	getScriptEngine(String language, PackageFinder packageFinder, StandardBindings bindings) Initializes the script engine for given language.
static ScriptEngine	getSecuredScriptEngine(String language, PackageFinder packageFinder, StandardBindings bindings, PermissionCollection permissions) This method is similar to the #getScriptEngine(String, PackageFinder, StandardBindings, ScriptSourceProvider...) method but additionally applies a security wrapper on the returned script engine so that the scripts execute with the provided java permissions.
static Set<String>	getSupportedLanguages()
static void	injectStandardBindings(ScriptEngine engine, StandardBindings bindings, boolean deleteExistingBindings, ScriptSourceProvider... scriptSourceProviders) Injects the values provided in the bindings into the engine scope of the provided script engine.
static void	reloadScriptEngineProviders(ClassLoader classLoader) Reloads the list of the known script engine providers using the given classloader or the current thread's context classloader if it is null.
static void	removeBindings(ScriptEngine engine, Set<RhqManager> keySet) Remove the specified bindings from the engine.

Methods inherited from class java.lang.Object

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

Method Detail

reloadScriptEngineProviders

public static void reloadScriptEngineProviders(ClassLoader classLoader)

Reloads the list of the known script engine providers using the given classloader or the current thread's context classloader if it is null.

Parameters:

classLoader - the classloader used to find the script engine providers on the classpath

Throws:

IllegalStateException - if more than 1 script engine provider is found for a single language

getSupportedLanguages

public static Set<String> getSupportedLanguages()

Returns:

the set of the scripting languages supported by this factory

getLanguageByScriptFileExtension

public static String getLanguageByScriptFileExtension(String fileExtension)

getFileExtensionForLanguage

public static String getFileExtensionForLanguage(String language)

getScriptEngine

public static ScriptEngine getScriptEngine(String language,
                           PackageFinder packageFinder,
                           StandardBindings bindings)
                                    throws ScriptException,
                                           IOException

Initializes the script engine for given language.

Parameters:

language - the language of the script to instantiate

packageFinder - the package finder to find the standard packages in user provided locations

bindings - the initial standard bindings or null if none required

Returns:

the initialized engine or null if a ScriptEngineProvider for given language isn't known.

Throws:

ScriptException - on error during initialization of the script environment

IOException - if the package finder fails to find the packages

getSecuredScriptEngine

public static ScriptEngine getSecuredScriptEngine(String language,
                                  PackageFinder packageFinder,
                                  StandardBindings bindings,
                                  PermissionCollection permissions)
                                           throws ScriptException,
                                                  IOException

This method is similar to the #getScriptEngine(String, PackageFinder, StandardBindings, ScriptSourceProvider...) method but additionally applies a security wrapper on the returned script engine so that the scripts execute with the provided java permissions.

Throws:

ScriptException

IOException

See Also:

#getScriptEngine(String, PackageFinder, StandardBindings, ScriptSourceProvider...)

injectStandardBindings

public static void injectStandardBindings(ScriptEngine engine,
                          StandardBindings bindings,
                          boolean deleteExistingBindings,
                          ScriptSourceProvider... scriptSourceProviders)

Injects the values provided in the bindings into the engine scope of the provided script engine.

Parameters:

engine - the engine

bindings - the bindings

deleteExistingBindings - true if the existing bindings should be replaced by the provided ones, false if the provided bindings should be added to the existing ones (possibly overwriting bindings with the same name).

scriptSourceProviders - the list of script source providers to be used by the script engine to locate the scripts. Note that the providers become associated with the script engine and its bindings and therefore should not be used with any other script engine. If the providers implement the StandardBindings.RhqFacadeChangeListener interface, they will be automatically hooked up with the bindings so that the providers will get notified whenever the rhq facade changes.

removeBindings

public static void removeBindings(ScriptEngine engine,
                  Set<RhqManager> keySet)

Remove the specified bindings from the engine.

Parameters:

engine - the engine

keySet - the binding keys to be removed

bindIndirectionMethods

public static void bindIndirectionMethods(ScriptEngine scriptEngine,
                          String bindingName)

Goes through the methods of the object found in the scriptEngine's ENGINE_SCOPE and for each of them generates a top-level function that is called the same name and accepts the same parameters.

Parameters:

scriptEngine - the script engine to generate the top-level functions in

bindingName - the name of the object in the script engine to generate the functions from

See Also:

ScriptEngineInitializer#generateIndirectionMethod(String, Method), NoTopLevelIndirection

getInitializer

public static ScriptEngineInitializer getInitializer(String language)

getCodeCompletion

public static CodeCompletion getCodeCompletion(String language)