This is the view of a scripting engine assumed by the bean scripting
framework. This interface is used when an application decides to
run some script under application control. (This is the reverse of
the more common situation, which is that of the scripting language
calling into the application.)
When a scripting engine is first fired up, the initialize()
method is called right after construction.
A scripting engine must provide two access points for applications
to call into them: via function calls and via expression evaluation.
It must also support loading scripts.
A scripting engine is a property change listener and will be notified
when any of the relevant properties of the manager change. (See
BSFManager to see which of its properties are bound.)
apply
public Object apply(String source,
int lineNo,
int columnNo,
Object funcBody,
Vector paramNames,
Vector arguments)
throws BSFException
This is used by an application to invoke an anonymous function. An
anonymous function is a multi-line script which when evaluated will
produce a value. These are separated from expressions and scripts
because the prior are spsed to be good 'ol expressions and scripts
are not value returning. We allow anonymous functions to have parameters
as well for completeness.
source
- (context info) the source of this expression
(e.g., filename)lineNo
- (context info) the line number in source for exprcolumnNo
- (context info) the column number in source for exprfuncBody
- the multi-line, value returning script to evaluateparamNames
- the names of the parameters above assumesarguments
- values of the above parameters
BSFException
- if anything goes wrong while doin' it.
call
public Object call(Object object,
String name,
Object[] args)
throws BSFException
This is used by an application to call into the scripting engine
to make a function/method call. The "object" argument is the object
whose method is to be called, if that applies. For non-OO languages,
this is typically ignored and should be given as null. For pretend-OO
languages such as VB, this would be the (String) name of the object.
The arguments are given in the args array.
object
- object on which to make the callname
- name of the method / procedure to callargs
- the arguments to be given to the procedure
BSFException
- if anything goes wrong while eval'ing a
BSFException is thrown. The reason indicates the problem.
compileApply
public void compileApply(String source,
int lineNo,
int columnNo,
Object funcBody,
Vector paramNames,
Vector arguments,
CodeBuffer cb)
throws BSFException
This is used by an application to compile an anonymous function. See
comments in apply for more hdetails.
source
- (context info) the source of this expression
(e.g., filename)lineNo
- (context info) the line number in source for exprcolumnNo
- (context info) the column number in source for exprfuncBody
- the multi-line, value returning script to evaluateparamNames
- the names of the parameters above assumesarguments
- values of the above parameterscb
- the CodeBuffer to compile into
BSFException
- if anything goes wrong while doin' it.
compileExpr
public void compileExpr(String source,
int lineNo,
int columnNo,
Object expr,
CodeBuffer cb)
throws BSFException
This is used by an application to compile a value-returning expression.
The expr may be string or some other type, depending on the language.
The generated code is dumped into the CodeBuffer.
source
- (context info) the source of this expression
(e.g., filename)lineNo
- (context info) the line number in source for exprcolumnNo
- (context info) the column number in source for exprexpr
- the expression to compilecb
- the CodeBuffer to compile into
BSFException
- if anything goes wrong while compiling a
BSFException is thrown. The reason indicates the problem.
compileScript
public void compileScript(String source,
int lineNo,
int columnNo,
Object script,
CodeBuffer cb)
throws BSFException
This is used by an application to compile some script. The
script may be string or some other type, depending on the
language. The generated code is dumped into the CodeBuffer.
source
- (context info) the source of this script
(e.g., filename)lineNo
- (context info) the line number in source for scriptcolumnNo
- (context info) the column number in source for scriptscript
- the script to compilecb
- the CodeBuffer to compile into
BSFException
- if anything goes wrong while compiling a
BSFException is thrown. The reason indicates the problem.
declareBean
public void declareBean(BSFDeclaredBean bean)
throws BSFException
Declare a bean after the engine has been started. Declared beans
are beans that are named and which the engine must make available
to the scripts it runs in the most first class way possible.
bean
- the bean to declare
BSFException
- if the engine cannot do this operation
disconnectedDebuggerNotify
public void disconnectedDebuggerNotify()
Notify the engine that the connection to its
debugger has been lost.
eval
public Object eval(String source,
int lineNo,
int columnNo,
Object expr)
throws BSFException
This is used by an application to evaluate an expression. The
expression may be string or some other type, depending on the
language. (For example, for BML it'll be an org.w3c.dom.Element
object.)
source
- (context info) the source of this expression
(e.g., filename)lineNo
- (context info) the line number in source for exprcolumnNo
- (context info) the column number in source for exprexpr
- the expression to evaluate
BSFException
- if anything goes wrong while eval'ing a
BSFException is thrown. The reason indicates the problem.
exec
public void exec(String source,
int lineNo,
int columnNo,
Object script)
throws BSFException
This is used by an application to execute some script. The
expression may be string or some other type, depending on the
language. Returns nothing but if something goes wrong it excepts
(of course).
source
- (context info) the source of this expression
(e.g., filename)lineNo
- (context info) the line number in source for exprcolumnNo
- (context info) the column number in source for exprscript
- the script to execute
BSFException
- if anything goes wrong while exec'ing a
BSFException is thrown. The reason indicates the problem.
getSpecificDebuggingInterface
public Object getSpecificDebuggingInterface()
The language-specific interface on the engine
for debugging...
initialize
public void initialize(BSFManager mgr,
String lang,
Vector declaredBeans)
throws BSFException
This method is used to initialize the engine right after construction.
This method will be called before any calls to eval or call. At this
time the engine should capture the current values of interesting
properties from the manager. In the future, any changes to those
will be mirrored to me by the manager via a property change event.
mgr
- The BSFManager that's hosting this engine.lang
- Language string which this engine is handling.declaredBeans
- Vector of BSFDeclaredObject containing beans
that should be declared into the language runtime at init
time as best as possible.
BSFException
- if anything goes wrong while init'ing a
BSFException is thrown. The reason indicates the problem.
placeBreakpointAtLine
public void placeBreakpointAtLine(int brkptid,
String docname,
int lineno)
throws BSFException
placeBreakpointAtOffset
public void placeBreakpointAtOffset(int brkptid,
String docname,
int offset)
throws BSFException
removeBreakpoint
public void removeBreakpoint(String docname,
int brkptid)
throws BSFException
setEntryExit
public void setEntryExit(String docname,
boolean on)
throws BSFException
terminate
public void terminate()
Graceful termination
undeclareBean
public void undeclareBean(BSFDeclaredBean bean)
throws BSFException
Undeclare a previously declared bean.
bean
- the bean to undeclare
BSFException
- if the engine cannot do this operation