org.apache.bsf
Class BSFManager

java.lang.Object
  org.apache.bsf.BSFManager

public class BSFManager

extends java.lang.Object

This class is the entry point to the bean scripting framework. An application wishing to integrate scripting to a Java app would place an instance of a BSFManager in their code and use its services to register the beans they want to make available for scripting, load scripting engines, and run scripts.

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), Rony G. Flatscher (added BSF_Log[Factory] to allow BSF to run without org.apache.commons.logging present)

Field Summary

protected java.lang.ClassLoader	classLoader
protected java.lang.String	classPath
protected java.util.Vector	declaredBeans
protected static java.lang.ClassLoader	definedClassLoader
protected static java.util.Hashtable	extn2Lang
protected java.util.Hashtable	loadedEngines
protected ObjectRegistry	objectRegistry
protected java.beans.PropertyChangeSupport	pcs
protected static java.util.Hashtable	registeredEngines
protected java.lang.String	tempDir
protected static java.lang.String	version

Constructor Summary

BSFManager()

Method Summary

java.lang.Object	apply(java.lang.String lang, java.lang.String source, int lineNo, int columnNo, java.lang.Object funcBody, java.util.Vector paramNames, java.util.Vector arguments) Apply the given anonymous function of the given language to the given parameters and return the resulting value.
void	compileApply(java.lang.String lang, java.lang.String source, int lineNo, int columnNo, java.lang.Object funcBody, java.util.Vector paramNames, java.util.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(java.lang.String lang, java.lang.String source, int lineNo, int columnNo, java.lang.Object expr, CodeBuffer cb) Compile the given expression of the given language into the given CodeBuffer.
void	compileScript(java.lang.String lang, java.lang.String source, int lineNo, int columnNo, java.lang.Object script, CodeBuffer cb) Compile the given script of the given language into the given CodeBuffer.
void	declareBean(java.lang.String beanName, java.lang.Object bean, java.lang.Class type) Declare a bean.
java.lang.Object	eval(java.lang.String lang, java.lang.String source, int lineNo, int columnNo, java.lang.Object expr) Evaluate the given expression of the given language and return the resulting value.
void	exec(java.lang.String lang, java.lang.String source, int lineNo, int columnNo, java.lang.Object script) Execute the given script of the given language.
java.lang.ClassLoader	getClassLoader() Get classLoader
java.lang.String	getClassPath() Get classPath
static java.lang.ClassLoader	getDefinedClassLoader() Returns the defined ClassLoader (the ClassLoader that got used to define the org.apache.bsf.BSFManager class object).
static java.lang.String	getLangFromFilename(java.lang.String fileName) Determine the language of a script file by looking at the file extension.
ObjectRegistry	getObjectRegistry() Return the current object registry of the manager.
java.lang.String	getTempDir() Get tempDir
static java.lang.String	getVersion() Returns the version string of BSF.
void	iexec(java.lang.String lang, java.lang.String source, int lineNo, int columnNo, java.lang.Object script) Execute the given script of the given language, attempting to emulate an interactive session w/ the language.
static boolean	isLanguageRegistered(java.lang.String lang) Determine whether a language is registered.
BSFEngine	loadScriptingEngine(java.lang.String lang) Load a scripting engine based on the lang string identifying it.
java.lang.Object	lookupBean(java.lang.String beanName) return a handle to a bean registered in the bean registry by the application or a scripting engine.
void	registerBean(java.lang.String beanName, java.lang.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(java.lang.String lang, java.lang.String engineClassName, java.lang.String[] extensions) Register a scripting engine in the static registry of the BSFManager.
void	setClassLoader(java.lang.ClassLoader classLoader) Set the class loader for those that need to use it.
void	setClassPath(java.lang.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(java.lang.String tempDir) Temporary directory to put stuff into (for those who need to).
void	terminate() Gracefully terminate all engines
void	undeclareBean(java.lang.String beanName) Undeclare a previously declared bean.
void	unregisterBean(java.lang.String beanName) Unregister a previously registered bean.

Methods inherited from class java.lang.Object

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

Field Detail

version

protected static java.lang.String version

registeredEngines

protected static java.util.Hashtable registeredEngines

extn2Lang

protected static java.util.Hashtable extn2Lang

definedClassLoader

protected static java.lang.ClassLoader definedClassLoader

loadedEngines

protected java.util.Hashtable loadedEngines

objectRegistry

protected ObjectRegistry objectRegistry

pcs

protected java.beans.PropertyChangeSupport pcs

classLoader

protected java.lang.ClassLoader classLoader

tempDir

protected java.lang.String tempDir

classPath

protected java.lang.String classPath

declaredBeans

protected java.util.Vector declaredBeans

Constructor Detail

BSFManager

public BSFManager()

Method Detail

getDefinedClassLoader

public static java.lang.ClassLoader getDefinedClassLoader()

Returns the defined ClassLoader (the ClassLoader that got used to define the org.apache.bsf.BSFManager class object).

Returns:

the defined ClassLoader instance

getVersion

public static java.lang.String 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: "244.20080623" stands for: BSF version 2.4.4 as of 2008-07-04.

Since:

2006-01-17

apply

public java.lang.Object apply(java.lang.String lang,
                              java.lang.String source,
                              int lineNo,
                              int columnNo,
                              java.lang.Object funcBody,
                              java.util.Vector paramNames,
                              java.util.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 identifier

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

funcBody - the multi-line, value returning script to evaluate

paramNames - the names of the parameters above assumes

arguments - values of the above parameters

Throws:

BSFException - if anything goes wrong while running the script

compileApply

public void compileApply(java.lang.String lang,
                         java.lang.String source,
                         int lineNo,
                         int columnNo,
                         java.lang.Object funcBody,
                         java.util.Vector paramNames,
                         java.util.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 identifier

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

funcBody - the multi-line, value returning script to evaluate

paramNames - the names of the parameters above assumes

arguments - values of the above parameters

cb - code buffer to compile into

Throws:

BSFException - if anything goes wrong while running the script

compileExpr

public void compileExpr(java.lang.String lang,
                        java.lang.String source,
                        int lineNo,
                        int columnNo,
                        java.lang.Object expr,
                        CodeBuffer cb)
                 throws BSFException

Compile the given expression of the given language into the given CodeBuffer.

Parameters:

lang - language identifier

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

expr - the expression to compile

cb - code buffer to compile into

Throws:

BSFException - if any error while compiling the expression

compileScript

public void compileScript(java.lang.String lang,
                          java.lang.String source,
                          int lineNo,
                          int columnNo,
                          java.lang.Object script,
                          CodeBuffer cb)
                   throws BSFException

Compile the given script of the given language into the given CodeBuffer.

Parameters:

lang - language identifier

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

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

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

script - the script to compile

cb - code buffer to compile into

Throws:

BSFException - if any error while compiling the script

declareBean

public void declareBean(java.lang.String beanName,
                        java.lang.Object bean,
                        java.lang.Class type)
                 throws BSFException

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 as

bean - the bean that's being declared

type - 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.

eval

public java.lang.Object eval(java.lang.String lang,
                             java.lang.String source,
                             int lineNo,
                             int columnNo,
                             java.lang.Object expr)
                      throws BSFException

Evaluate the given expression of the given language and return the resulting value.

Parameters:

lang - language identifier

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

expr - the expression to evaluate

Throws:

BSFException - if anything goes wrong while running the script

exec

public void exec(java.lang.String lang,
                 java.lang.String source,
                 int lineNo,
                 int columnNo,
                 java.lang.Object script)
          throws BSFException

Execute the given script of the given language.

Parameters:

lang - language identifier

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

Throws:

BSFException - if anything goes wrong while running the script

iexec

public void iexec(java.lang.String lang,
                  java.lang.String source,
                  int lineNo,
                  int columnNo,
                  java.lang.Object script)
           throws BSFException

Execute the given script of the given language, attempting to emulate an interactive session w/ the language.

Parameters:

lang - language identifier

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

Throws:

BSFException - if anything goes wrong while running the script

getClassLoader

public java.lang.ClassLoader getClassLoader()

Get classLoader

getClassPath

public java.lang.String getClassPath()

Get classPath

getLangFromFilename

public static java.lang.String getLangFromFilename(java.lang.String fileName)
                                            throws BSFException

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.

getObjectRegistry

public ObjectRegistry getObjectRegistry()

Return the current object registry of the manager.

Returns:

the current registry.

getTempDir

public java.lang.String getTempDir()

Get tempDir

isLanguageRegistered

public static boolean isLanguageRegistered(java.lang.String lang)

Determine whether a language is registered.

Parameters:

lang - string identifying a language

Returns:

true iff it is

loadScriptingEngine

public BSFEngine loadScriptingEngine(java.lang.String lang)
                              throws BSFException

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.

lookupBean

public java.lang.Object lookupBean(java.lang.String beanName)

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

registerBean

public void registerBean(java.lang.String beanName,
                         java.lang.Object bean)

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 under

bean - the bean to register

registerScriptingEngine

public static void registerScriptingEngine(java.lang.String lang,
                                           java.lang.String engineClassName,
                                           java.lang.String[] extensions)

Register a scripting engine in the static registry of the BSFManager.

Parameters:

lang - string identifying language

engineClassName - 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.

setClassLoader

public void setClassLoader(java.lang.ClassLoader classLoader)

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.

setClassPath

public void setClassPath(java.lang.String classPath)

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

setObjectRegistry

public void setObjectRegistry(ObjectRegistry objectRegistry)

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

setTempDir

public void setTempDir(java.lang.String tempDir)

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

terminate

public void terminate()

Gracefully terminate all engines

undeclareBean

public void undeclareBean(java.lang.String beanName)
                   throws BSFException

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.

unregisterBean

public void unregisterBean(java.lang.String beanName)

Unregister a previously registered bean. Silent if name is not found.

Parameters:

beanName - name of bean to unregister