Class BSFManager
BSFManager serves as the registry of available scripting engines as well. Loading and unloading of scripting engines is supported as well. Each BSFManager loads one engine per language. Several BSFManagers can be created per JVM.
- Author:
- Sanjiva Weerawarana, Matthew J. Duftler, Sam Ruby, Olivier Gruber (added original debugging support), Don Schwarz (added support for registering languages dynamically)
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected ClassLoader
protected String
protected Vector
protected static Hashtable
protected Hashtable
protected ObjectRegistry
protected PropertyChangeSupport
protected static Hashtable
protected String
protected static String
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionapply
(String lang, String source, int lineNo, int columnNo, Object funcBody, Vector paramNames, Vector arguments) Apply the given anonymous function of the given language to the given parameters and return the resulting value.void
compileApply
(String lang, String source, int lineNo, int columnNo, Object funcBody, Vector paramNames, Vector arguments, CodeBuffer cb) Compile the application of the given anonymous function of the given language to the given parameters into the given CodeBuffer.void
compileExpr
(String lang, String source, int lineNo, int columnNo, Object expr, CodeBuffer cb) Compile the given expression of the given language into the given CodeBuffer.void
compileScript
(String lang, String source, int lineNo, int columnNo, Object script, CodeBuffer cb) Compile the given script of the given language into the given CodeBuffer.void
declareBean
(String beanName, Object bean, Class type) Declare a bean.Evaluate the given expression of the given language and return the resulting value.void
Execute the given script of the given language.Get classLoaderGet classPathstatic String
getLangFromFilename
(String fileName) Determine the language of a script file by looking at the file extension.Return the current object registry of the manager.Get tempDirstatic String
Returns the version string of BSF.void
Execute the given script of the given language, attempting to emulate an interactive session w/ the language.static boolean
isLanguageRegistered
(String lang) Determine whether a language is registered.loadScriptingEngine
(String lang) Load a scripting engine based on the lang string identifying it.lookupBean
(String beanName) return a handle to a bean registered in the bean registry by the application or a scripting engine.void
registerBean
(String beanName, Object bean) Registering a bean allows a scripting engine or the application to access that bean by name and to manipulate it.static void
registerScriptingEngine
(String lang, String engineClassName, String[] extensions) Register a scripting engine in the static registry of the BSFManager.void
setClassLoader
(ClassLoader classLoader) Set the class loader for those that need to use it.void
setClassPath
(String classPath) Set the classpath for those that need to use it.void
setObjectRegistry
(ObjectRegistry objectRegistry) Set the object registry used by this manager.void
setTempDir
(String tempDir) Temporary directory to put stuff into (for those who need to).void
Gracefully terminate all enginesvoid
undeclareBean
(String beanName) Undeclare a previously declared bean.void
unregisterBean
(String beanName) Unregister a previously registered bean.
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Field Details
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version
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registeredEngines
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extn2Lang
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loadedEngines
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objectRegistry
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pcs
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classLoader
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tempDir
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classPath
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declaredBeans
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Constructor Details
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BSFManager
public BSFManager()
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Method Details
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getVersion
Returns the version string of BSF.- Returns:
- version string in the form "abc.yyyymmdd" where
"abc" represents a dewey decimal number (three levels, each between 0 and 9), and
"yyyy" a four digit year, "mm" a two digit month,
"dd" a two digit day.
Example: "240.20061006
" stands for: BSF version2.4.0
as of2006-10-06
. - Since:
- 2006-01-17
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apply
public Object apply(String lang, String source, int lineNo, int columnNo, Object funcBody, Vector paramNames, Vector arguments) throws BSFException Apply the given anonymous function of the given language to the given parameters and return the resulting value.- Parameters:
lang
- language identifiersource
- (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- Throws:
BSFException
- if anything goes wrong while running the script
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compileApply
public void compileApply(String lang, String source, int lineNo, int columnNo, Object funcBody, Vector paramNames, Vector arguments, CodeBuffer cb) throws BSFException Compile the application of the given anonymous function of the given language to the given parameters into the given CodeBuffer.- Parameters:
lang
- language identifiersource
- (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
- code buffer to compile into- Throws:
BSFException
- if anything goes wrong while running the script
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compileExpr
public void compileExpr(String lang, String source, int lineNo, int columnNo, Object expr, CodeBuffer cb) throws BSFException Compile the given expression of the given language into the given CodeBuffer.- Parameters:
lang
- language identifiersource
- (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
- code buffer to compile into- Throws:
BSFException
- if any error while compiling the expression
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compileScript
public void compileScript(String lang, String source, int lineNo, int columnNo, Object script, CodeBuffer cb) throws BSFException Compile the given script of the given language into the given CodeBuffer.- Parameters:
lang
- language identifiersource
- (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
- code buffer to compile into- Throws:
BSFException
- if any error while compiling the script
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declareBean
Declare a bean. The difference between declaring and registering is that engines are spsed to make declared beans "pre-available" in the scripts as far as possible. That is, if a script author needs a registered bean, he needs to look it up in some way. However if he needs a declared bean, the language has the responsibility to make those beans avaialable "automatically."When a bean is declared it is automatically registered as well so that any declared bean can be gotton to by looking it up as well.
If any of the languages that are already running in this manager says they don't like this (by throwing an exception) then this method will simply quit with that exception. That is, any engines that come after than in the engine enumeration will not even be told about this new bean.
So, in general its best to declare beans before the manager has been asked to load any engines because then the user can be informed when an engine rejects it. Also, its much more likely that an engine can declare a bean at start time than it can at any time.
- Parameters:
beanName
- name to declare bean asbean
- the bean that's being declaredtype
- the type to represent the bean as- Throws:
BSFException
- if any of the languages that are already running decides to throw an exception when asked to declare this bean.
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eval
public Object eval(String lang, String source, int lineNo, int columnNo, Object expr) throws BSFException Evaluate the given expression of the given language and return the resulting value.- Parameters:
lang
- language identifiersource
- (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- Throws:
BSFException
- if anything goes wrong while running the script
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exec
public void exec(String lang, String source, int lineNo, int columnNo, Object script) throws BSFException Execute the given script of the given language.- Parameters:
lang
- language identifiersource
- (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- Throws:
BSFException
- if anything goes wrong while running the script
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iexec
public void iexec(String lang, String source, int lineNo, int columnNo, Object script) throws BSFException Execute the given script of the given language, attempting to emulate an interactive session w/ the language.- Parameters:
lang
- language identifiersource
- (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- Throws:
BSFException
- if anything goes wrong while running the script
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getClassLoader
Get classLoader -
getClassPath
Get classPath -
getLangFromFilename
Determine the language of a script file by looking at the file extension.- Parameters:
fileName
- the name of the file- Returns:
- the scripting language the file is in if the file extension is known to me (must have been registered via registerScriptingEngine).
- Throws:
BSFException
- if file's extension is unknown.
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getObjectRegistry
Return the current object registry of the manager.- Returns:
- the current registry.
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getTempDir
Get tempDir -
isLanguageRegistered
Determine whether a language is registered.- Parameters:
lang
- string identifying a language- Returns:
- true iff it is
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loadScriptingEngine
Load a scripting engine based on the lang string identifying it.- Parameters:
lang
- string identifying language- Throws:
BSFException
- if the language is unknown (i.e., if it has not been registered) with a reason of REASON_UNKNOWN_LANGUAGE. If the language is known but if the interface can't be created for some reason, then the reason is set to REASON_OTHER_ERROR and the actual exception is passed on as well.
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lookupBean
return a handle to a bean registered in the bean registry by the application or a scripting engine. Returns null if bean is not found.- Parameters:
beanName
- name of bean to look up- Returns:
- the bean if its found or null
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registerBean
Registering a bean allows a scripting engine or the application to access that bean by name and to manipulate it.- Parameters:
beanName
- name to register underbean
- the bean to register
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registerScriptingEngine
public static void registerScriptingEngine(String lang, String engineClassName, String[] extensions) Register a scripting engine in the static registry of the BSFManager.- Parameters:
lang
- string identifying languageengineClassName
- fully qualified name of the class interfacing the language to BSF.extensions
- array of file extensions that should be mapped to this language type. may be null.
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setClassLoader
Set the class loader for those that need to use it. Default is he who loaded me or null (i.e., its Class.forName).- Parameters:
classLoader
- the class loader to use.
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setClassPath
Set the classpath for those that need to use it. Default is the value of the java.class.path property.- Parameters:
classPath
- the classpath to use
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setObjectRegistry
Set the object registry used by this manager. By default a new one is created when the manager is new'ed and this overwrites that one.- Parameters:
objectRegistry
- the registry to use
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setTempDir
Temporary directory to put stuff into (for those who need to). Note that unless this directory is in the classpath or unless the classloader knows to look in here, any classes here will not be found! BSFManager provides a service method to load a class which uses either the classLoader provided by the class loader property or, if that fails, a class loader which knows to load from the tempdir to try to load the class. Default value of tempDir is "." (current working dir).- Parameters:
tempDir
- the temporary directory
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terminate
public void terminate()Gracefully terminate all engines -
undeclareBean
Undeclare a previously declared bean. This removes the bean from the list of declared beans in the manager as well as asks every running engine to undeclared the bean. As with above, if any of the engines except when asked to undeclare, this method does not catch that exception. Quietly returns if the bean is unknown.- Parameters:
beanName
- name of bean to undeclare- Throws:
BSFException
- if any of the languages that are already running decides to throw an exception when asked to undeclare this bean.
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unregisterBean
Unregister a previously registered bean. Silent if name is not found.- Parameters:
beanName
- name of bean to unregister
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