org.apache.bsf.util
Class EngineUtils

java.lang.Object
  org.apache.bsf.util.EngineUtils

public class EngineUtils

extends java.lang.Object

This class contains utilities that language integrators can use when implementing the BSFEngine interface.

Author:

Sanjiva Weerawarana, Sam Ruby, Rony G. Flatscher (added addEventListenerReturningEventInfos)

Field Summary

(package private) static boolean	bMethodHasSetAccessible
(package private) static BSFClassLoader	bsfCL
(package private) static java.lang.ClassLoader	bsfManagerDefinedCL

Constructor Summary

EngineUtils()

Method Summary

static void	addEventListener(java.lang.Object bean, java.lang.String eventSetName, java.lang.String filter, BSFEngine engine, BSFManager manager, java.lang.String source, int lineNo, int columnNo, java.lang.Object script) Add a script as a listener to some event coming out of an object.
static void	addEventListenerReturningEventInfos(java.lang.Object bean, java.lang.String eventSetName, java.lang.String filter, BSFEngine engine, BSFManager manager, java.lang.String source, int lineNo, int columnNo, java.lang.Object script, java.lang.Object dataFromScriptingEngine) Add a script as a listener to some event coming out of an object.
static java.lang.Object	callBeanMethod(java.lang.Object bean, java.lang.String methodName, java.lang.Object[] args) Finds and invokes a method with the given signature on the given bean.
static java.lang.Object	createBean(java.lang.String className, java.lang.Object[] args) Creates a new bean.
static java.lang.String	getTypeSignatureString(java.lang.Class cl) Given a class return the type signature string fragment for it.
static java.lang.Class	loadClass(BSFManager mgr, java.lang.String name) Loads a class using the following sequence of class loaders: Thread's context class loader, settable class loader stored with BSFManager, BSFManager's defining class loader, BSF customized class loader (from the BSFManager's temporary directory).

Methods inherited from class java.lang.Object

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

Field Detail

bsfCL

static BSFClassLoader bsfCL

bsfManagerDefinedCL

static java.lang.ClassLoader bsfManagerDefinedCL

bMethodHasSetAccessible

static boolean bMethodHasSetAccessible

Constructor Detail

EngineUtils

public EngineUtils()

Method Detail

addEventListener

public static void addEventListener(java.lang.Object bean,
                                    java.lang.String eventSetName,
                                    java.lang.String filter,
                                    BSFEngine engine,
                                    BSFManager manager,
                                    java.lang.String source,
                                    int lineNo,
                                    int columnNo,
                                    java.lang.Object script)
                             throws BSFException

Add a script as a listener to some event coming out of an object. The first two args identify the src of the event and the event set and the rest identify the script which should be run when the event fires.

Parameters:

bean - event source

eventSetName - name of event set from event src to bind to

filter - filter for events

engine - BSFEngine which can run this script

manager - BSFManager of the above engine

source - (context info) the source of this expression (e.g., filename)

lineNo - (context info) the line number in source for expr

columnNo - (context info) the column number in source for expr

script - the script to execute when the event occurs

Throws:

BSFException - if anything goes wrong while running the script

addEventListenerReturningEventInfos

public static void addEventListenerReturningEventInfos(java.lang.Object bean,
                                                       java.lang.String eventSetName,
                                                       java.lang.String filter,
                                                       BSFEngine engine,
                                                       BSFManager manager,
                                                       java.lang.String source,
                                                       int lineNo,
                                                       int columnNo,
                                                       java.lang.Object script,
                                                       java.lang.Object dataFromScriptingEngine)
                                                throws BSFException

Add a script as a listener to some event coming out of an object. The first two args identify the src of the event and the event set and the rest identify the script which should be run when the event fires. The processing will use the engine's apply() method.

Parameters:

bean - event source

eventSetName - name of event set from event src to bind to

filter - filter for events

engine - BSFEngine which can run this script

manager - BSFManager of the above engine

source - (context info) the source of this expression (e.g., filename)

lineNo - (context info) the line number in source for expr

columnNo - (context info) the column number in source for expr

script - the script to execute when the event occurs

dataFromScriptingEngine - this contains any object supplied by the scripting engine and gets sent back with the supplied script, if the event occurs. This could be used e.g. for indicating to the scripting engine which scripting engine object/routine/function/procedure should be ultimately informed of the event occurrence.

Throws:

BSFException - if anything goes wrong while running the script

callBeanMethod

public static java.lang.Object callBeanMethod(java.lang.Object bean,
                                              java.lang.String methodName,
                                              java.lang.Object[] args)
                                       throws BSFException

Finds and invokes a method with the given signature on the given bean. The signature of the method that's invoked is first taken as the types of the args, but if that fails, this tries to convert any primitive wrapper type args to their primitive counterparts to see whether a method exists that way. If it does, done.

Parameters:

bean - the object on which to invoke the method

methodName - name of the method

args - arguments to be given to the method

Returns:

the result of invoking the method, if any

Throws:

BSFException - if something goes wrong

createBean

public static java.lang.Object createBean(java.lang.String className,
                                          java.lang.Object[] args)
                                   throws BSFException

Creates a new bean. The signature of the constructor that's invoked is first taken as the types of the args, but if that fails, this tries to convert any primitive wrapper type args to their primitive counterparts to see whether a method exists that way. If it does, done.

Parameters:

className - fully qualified name of class to instantiate

args - array of constructor args (or null if none)

Returns:

the created bean

Throws:

BSFException - if something goes wrong (@see org.apache.cs.util.MethodUtils for the real exceptions that can occur).

getTypeSignatureString

public static java.lang.String getTypeSignatureString(java.lang.Class cl)

Given a class return the type signature string fragment for it. That is, return "I" for int, "J" for long, ... etc..

Parameters:

cl - class object for whom the signature fragment is needed.

Returns:

the string representing the type signature

loadClass

public static java.lang.Class loadClass(BSFManager mgr,
                                        java.lang.String name)
                                 throws BSFException

Loads a class using the following sequence of class loaders: Thread's context class loader, settable class loader stored with BSFManager, BSFManager's defining class loader, BSF customized class loader (from the BSFManager's temporary directory).

Parameters:

mgr - BSFManager who's classLoader and tempDir props are consulted

name - name of the class to load

Returns:

the loaded class

Throws:

BSFException - if something goes wrong.