org.apache.bsf.util
Class BSFEngineImpl

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

All Implemented Interfaces:

BSFEngine, java.util.EventListener, java.beans.PropertyChangeListener

Direct Known Subclasses:

fakeEngine, JaclEngine, JavaClassEngine, JavaEngine, JavaScriptEngine, JythonEngine, NetRexxEngine, XSLTEngine

public abstract class BSFEngineImpl

extends java.lang.Object

implements BSFEngine

This is a base implementation of the BSFEngine interface which engine implementations may choose to extend to get the basic methods of the interface implemented.

Author:

Sanjiva Weerawarana, Olivier Gruber (added original debugging support)

Field Summary

protected java.lang.ClassLoader	classLoader
protected java.lang.String	classPath
protected java.util.Vector	declaredBeans
protected java.lang.String	lang
protected BSFManager	mgr
protected java.lang.String	tempDir

Constructor Summary

BSFEngineImpl()

Method Summary

java.lang.Object	apply(java.lang.String source, int lineNo, int columnNo, java.lang.Object funcBody, java.util.Vector paramNames, java.util.Vector arguments) Default impl of apply - calls eval ignoring parameters and returns the result.
void	compileApply(java.lang.String source, int lineNo, int columnNo, java.lang.Object funcBody, java.util.Vector paramNames, java.util.Vector arguments, CodeBuffer cb) Default impl of compileApply - calls compileExpr ignoring parameters.
void	compileExpr(java.lang.String source, int lineNo, int columnNo, java.lang.Object expr, CodeBuffer cb) Default impl of compileExpr - generates code that'll create a new manager, evaluate the expression, and return the value.
void	compileScript(java.lang.String source, int lineNo, int columnNo, java.lang.Object script, CodeBuffer cb) Default impl of compileScript - generates code that'll create a new manager, and execute the script.
void	declareBean(BSFDeclaredBean bean) Declare a bean after the engine has been started.
void	exec(java.lang.String source, int lineNo, int columnNo, java.lang.Object script) Default impl of execute - calls eval and ignores the result.
void	iexec(java.lang.String source, int lineNo, int columnNo, java.lang.Object script) Default impl of interactive execution - calls eval and ignores the result.
void	initialize(BSFManager mgr, java.lang.String lang, java.util.Vector declaredBeans) initialize the engine; called right after construction by the manager.
void	propertyChange(java.beans.PropertyChangeEvent e) Receive property change events from the manager and update my fields as needed.
void	terminate() Graceful termination
void	undeclareBean(BSFDeclaredBean bean) Undeclare a previously declared bean.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.bsf.BSFEngine

call, eval

Field Detail

mgr

protected BSFManager mgr

lang

protected java.lang.String lang

declaredBeans

protected java.util.Vector declaredBeans

classPath

protected java.lang.String classPath

tempDir

protected java.lang.String tempDir

classLoader

protected java.lang.ClassLoader classLoader

Constructor Detail

BSFEngineImpl

public BSFEngineImpl()

Method Detail

apply

public java.lang.Object apply(java.lang.String source,
                              int lineNo,
                              int columnNo,
                              java.lang.Object funcBody,
                              java.util.Vector paramNames,
                              java.util.Vector arguments)
                       throws BSFException

Default impl of apply - calls eval ignoring parameters and returns the result.

Specified by:

apply in interface BSFEngine

Parameters:

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 doin' it.

compileApply

public void compileApply(java.lang.String source,
                         int lineNo,
                         int columnNo,
                         java.lang.Object funcBody,
                         java.util.Vector paramNames,
                         java.util.Vector arguments,
                         CodeBuffer cb)
                  throws BSFException

Default impl of compileApply - calls compileExpr ignoring parameters.

Specified by:

compileApply in interface BSFEngine

Parameters:

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 - the CodeBuffer to compile into

Throws:

BSFException - if anything goes wrong while doin' it.

compileExpr

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

Default impl of compileExpr - generates code that'll create a new manager, evaluate the expression, and return the value.

Specified by:

compileExpr in interface BSFEngine

Parameters:

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 - the CodeBuffer to compile into

Throws:

BSFException - if anything goes wrong while compiling a BSFException is thrown. The reason indicates the problem.

compileScript

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

Default impl of compileScript - generates code that'll create a new manager, and execute the script.

Specified by:

compileScript in interface BSFEngine

Parameters:

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 - the CodeBuffer to compile into

Throws:

BSFException - if anything goes wrong while compiling a BSFException is thrown. The reason indicates the problem.

declareBean

public void declareBean(BSFDeclaredBean bean)
                 throws BSFException

Description copied from interface: BSFEngine

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.

Specified by:

declareBean in interface BSFEngine

Parameters:

bean - the bean to declare

Throws:

BSFException - if the engine cannot do this operation

exec

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

Default impl of execute - calls eval and ignores the result.

Specified by:

exec in interface BSFEngine

Parameters:

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 exec'ing a BSFException is thrown. The reason indicates the problem.

iexec

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

Default impl of interactive execution - calls eval and ignores the result.

Specified by:

iexec in interface BSFEngine

Parameters:

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 exec'ing a BSFException is thrown. The reason indicates the problem.

initialize

public void initialize(BSFManager mgr,
                       java.lang.String lang,
                       java.util.Vector declaredBeans)
                throws BSFException

initialize the engine; called right after construction by the manager. Declared beans are simply kept in a vector and that's it. Subclasses must do whatever they want with it.

Specified by:

initialize in interface BSFEngine

Parameters:

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.

Throws:

BSFException - if anything goes wrong while init'ing a BSFException is thrown. The reason indicates the problem.

propertyChange

public void propertyChange(java.beans.PropertyChangeEvent e)

Receive property change events from the manager and update my fields as needed.

Specified by:

propertyChange in interface java.beans.PropertyChangeListener

Parameters:

e - PropertyChange event with the change data

terminate

public void terminate()

Description copied from interface: BSFEngine

Graceful termination

Specified by:

terminate in interface BSFEngine

undeclareBean

public void undeclareBean(BSFDeclaredBean bean)
                   throws BSFException

Description copied from interface: BSFEngine

Undeclare a previously declared bean.

Specified by:

undeclareBean in interface BSFEngine

Parameters:

bean - the bean to undeclare

Throws:

BSFException - if the engine cannot do this operation