bsh

Class Interpreter

java.lang.Object

bsh.Interpreter

All Implemented Interfaces:

BshClassManager.Listener, java.io.Serializable, java.lang.Runnable

public class Interpreter
extends java.lang.Object
implements java.lang.Runnable, java.io.Serializable, BshClassManager.Listener

The BeanShell script interpreter. An instance of Interpreter can be used to source scripts and evaluate statements or expressions.

Here are some examples:

        Interpeter bsh = new Interpreter();

        // Evaluate statements and expressions
        bsh.eval("foo=Math.sin(0.5)");
        bsh.eval("bar=foo*5; bar=Math.cos(bar);");
        bsh.eval("for(i=0; i<10; i++) { print(\"hello\"); }");
        // same as above using java syntax and apis only
        bsh.eval("for(int i=0; i<10; i++) { System.out.println(\"hello\"); }");

        // Source from files or streams
        bsh.source("myscript.bsh");  // or bsh.eval("source(\"myscript.bsh\")");

        // Use set() and get() to pass objects in and out of variables
        bsh.set( "date", new Date() );
        Date date = (Date)bsh.get( "date" );
        // This would also work:
        Date date = (Date)bsh.eval( "date" );

        bsh.eval("year = date.getYear()");
        Integer year = (Integer)bsh.get("year");  // primitives use wrappers

        // With Java1.3+ scripts can implement arbitrary interfaces...
        // Script an awt event handler (or source it from a file, more likely)
        bsh.eval( "actionPerformed( e ) { print( e ); }");
        // Get a reference to the script object (implementing the interface)
        ActionListener scriptedHandler =
            (ActionListener)bsh.eval("return (ActionListener)this");
        // Use the scripted event handler normally...
        new JButton.addActionListener( script );
    

In the above examples we showed a single interpreter instance, however you may wish to use many instances, depending on the application and how you structure your scripts. Interpreter instances are very light weight to create, however if you are going to execute the same script repeatedly and require maximum performance you should consider scripting the code as a method and invoking the scripted method each time on the same interpreter instance (using eval()).

See the BeanShell User's Manual for more information.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Interpreter.Console

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	COMPATIBIILTY
static java.lang.ThreadLocal<java.lang.Boolean>	DEBUG
protected boolean	evalOnly
protected boolean	interactive
static MainSecurityGuard	mainSecurityGuard It's the main security guard used by all instances of the Interpreter to prevent the execution of dangerous code
static boolean	TRACE
static java.lang.String	VERSION

Constructor Summary

Constructors

Constructor and Description
Interpreter() A non interactive interpreter for evaluation purposes only.
Interpreter(ConsoleAssignable console, boolean interactive, NameSpace namespace, Interpreter parent, java.lang.String sourceFileInfo) The main constructor, all other constructors should pass through here.
Interpreter(ConsoleInterface console) An interactive interpreter attached to a console, no namespace or parent.
Interpreter(ConsoleInterface console, Interpreter parent) An interactive interpreter attached to a console using parent namesepace.
Interpreter(ConsoleInterface console, NameSpace globalNameSpace) An interactive interpreter attached to a console with supplied namespace.
Interpreter(ConsoleInterface console, NameSpace namespace, Interpreter parent) An interactive interpreter attached to the specified console.
Interpreter(Interpreter parent) Extend existing interpreter.
Interpreter(NameSpace namespace) A non interactive interpreter for namespace.
Interpreter(NameSpace namespace, Interpreter parent) A non interactive interpreter for namespace and parent.
Interpreter(NameSpace namespace, Interpreter parent, java.lang.String sourceFileInfo) A non interactive interpreter for namespace, parent and source file.
Interpreter(NameSpace namespace, java.lang.String sourceFileInfo) A non interactive interpreter for namespace and source file.
Interpreter(java.io.Reader in, java.io.PrintStream out, java.io.PrintStream err, boolean interactive) Interpreter instance without a namespace, parent and source file.
Interpreter(java.io.Reader in, java.io.PrintStream out, java.io.PrintStream err, boolean interactive, NameSpace namespace) Interpreter instance without a parent interpreter and source file.
Interpreter(java.io.Reader in, java.io.PrintStream out, java.io.PrintStream err, boolean interactive, NameSpace namespace, Interpreter parent, java.lang.String sourceFileInfo) Wraps individual input output streams as a console collection.

Method Summary

Modifier and Type	Method and Description
void	classLoaderChanged()
static void	debug(java.lang.Object... msg) Print a debug message on debug stream associated with this interpreter only if debugging is turned on.
void	error(java.lang.Object o)
java.lang.Object	eval(java.io.Reader in) Evaluate the inputstream in this interpreter's global namespace.
java.lang.Object	eval(java.io.Reader in, NameSpace nameSpace, java.lang.String sourceFileInfo) Spawn a non-interactive local interpreter to evaluate text in the specified namespace.
java.lang.Object	eval(java.lang.String statements) Evaluate the string in this interpreter's global namespace.
java.lang.Object	eval(java.lang.String statements, NameSpace nameSpace) Evaluate the string in the specified namespace.
java.lang.Object	get(java.lang.String name) Get the value of the name.
BshClassManager	getClassManager() Get the class manager associated with this interpreter (the BshClassManager of this interpreter's global namespace).
boolean	getCompatibility() Compatibility mode.
java.io.PrintStream	getErr()
java.io.Reader	getIn() Console delegate methods.
java.lang.Object	getInterface(java.lang.Class<?> interf) Get a reference to the interpreter (global namespace), cast to the specified interface type.
NameSpace	getNameSpace() Retrieve the global namespace for this interpreter.
java.io.PrintStream	getOut()
Interpreter	getParent() Get the parent Interpreter of this interpreter, if any.
static boolean	getSaveClasses()
static java.lang.String	getSaveClassesDir()
boolean	getShowResults() Show on/off verbose printing status for the show() command.
java.lang.String	getSourceFileInfo() Specify the source of the text from which this interpreter is reading.
boolean	getStrictJava()
static void	invokeMain(java.lang.Class<?> clas, java.lang.String[] args) Convenience method for invoking the main method of a class.
static void	main(java.lang.String[] args) Interactive interpreter command line execution.
java.io.File	pathToFile(java.lang.String fileName) Localize a path to the file name based on the bsh.cwd interpreter working directory.
void	print(java.lang.Object o)
void	println(java.lang.Object o)
static void	redirectOutputToFile(java.lang.String filename) Deprecated. redirects global JVM streams rather than any specific interpreter's own streams. Use setOutputFile(String) to redirect a particular interpreter's output.
void	reset() Optional method to release additional resources.
void	run() Run interactively.
void	set(java.lang.String name, boolean value)
void	set(java.lang.String name, double value)
void	set(java.lang.String name, float value)
void	set(java.lang.String name, int value)
void	set(java.lang.String name, long value)
void	set(java.lang.String name, java.lang.Object value) Assign the value to the name.
void	setClassLoader(java.lang.ClassLoader externalCL) Set an external class loader to be used as the base classloader for BeanShell.
void	setCompatibility(boolean value) Setting compatibility mode.
void	setConsole(ConsoleAssignable console) Attach an assignable console and initialize a new parser.
void	setConsole(ConsoleInterface console) Overloaded to accept a read only console.
void	setErr(java.io.PrintStream err)
void	setExitOnEOF(boolean value) Specify whether, in interactive mode, the interpreter exits Java upon end of input.
void	setIn(java.io.Reader in)
void	setNameSpace(NameSpace namespace) Assign the global namespace for this interpreter.
void	setOut(java.io.PrintStream out)
void	setOutputFile(java.lang.String filename) Redirect this interpreter's own output and error streams to a file, leaving System.out / System.err untouched.
void	setShowResults(boolean showResults) Turn on/off the verbose printing of results as for the show() command.
static void	setShutdownOnExit(boolean value) Shared system object visible under bsh.system
void	setStrictJava(boolean b) Set strict Java mode on or off.
void	setYieldDelay(int delay) Set thread yield delay time in milliseconds.
java.lang.Object	source(java.io.File file) Source a script from a file for interpretation.
java.lang.Object	source(java.io.File file, NameSpace namespace) Source a script from a file for interpretation.
java.lang.Object	source(java.lang.String filename) Source a script from a filename for interpretation.
java.lang.Object	source(java.lang.String filename, NameSpace namespace) Source a script from a filename for interpretation.
java.lang.Object	source(java.net.URL url) Source a script from a url for interpretation.
java.lang.Object	source(java.net.URL url, NameSpace namespace) Source a script from a url for interpretation.
void	unset(java.lang.String name) Unassign the variable name.

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

public static final java.lang.ThreadLocal<java.lang.Boolean> DEBUG

TRACE

public static boolean TRACE

COMPATIBIILTY

public static boolean COMPATIBIILTY

VERSION

public static final java.lang.String VERSION

mainSecurityGuard

public static final MainSecurityGuard mainSecurityGuard

It's the main security guard used by all instances of the Interpreter to prevent the execution of dangerous code

evalOnly

protected boolean evalOnly

interactive

protected boolean interactive

Constructor Detail

Interpreter

public Interpreter(ConsoleAssignable console,
                   boolean interactive,
                   NameSpace namespace,
                   Interpreter parent,
                   java.lang.String sourceFileInfo)

The main constructor, all other constructors should pass through here. If namespace is not null it becomes this interpreter's global namespace otherwise a new instance is created. A parent interpreter allows values to be inherited like a shared class manager.

Parameters:

console - assignable collection of input output streams.

interactive - whether attached to user input.

namespace - global name space or null.

parent - interpreter or null.

sourceFileInfo - source file info for debugging or null.

Interpreter

public Interpreter(java.io.Reader in,
                   java.io.PrintStream out,
                   java.io.PrintStream err,
                   boolean interactive,
                   NameSpace namespace,
                   Interpreter parent,
                   java.lang.String sourceFileInfo)

Wraps individual input output streams as a console collection.

Parameters:

in - input stream.

out - standard output stream.

err - error output stream.

interactive - whether attached to user input.

namespace - global name space or null.

parent - interpreter or null.

sourceFileInfo - source file info for debugging or null.

Interpreter

public Interpreter(java.io.Reader in,
                   java.io.PrintStream out,
                   java.io.PrintStream err,
                   boolean interactive,
                   NameSpace namespace)

Interpreter instance without a parent interpreter and source file.

Parameters:

in - input stream.

out - standard output stream.

err - error output stream.

interactive - whether attached to user input.

namespace - global name space or null.

Interpreter

public Interpreter(java.io.Reader in,
                   java.io.PrintStream out,
                   java.io.PrintStream err,
                   boolean interactive)

Interpreter instance without a namespace, parent and source file.

Parameters:

in - input stream.

out - standard output stream.

err - error output stream.

interactive - whether attached to user input.

Interpreter

public Interpreter(ConsoleInterface console,
                   NameSpace namespace,
                   Interpreter parent)

An interactive interpreter attached to the specified console.

Parameters:

console - read only collection of input output streams.

namespace - global name space or null.

parent - interpreter or null.

Interpreter

public Interpreter(ConsoleInterface console,
                   Interpreter parent)

An interactive interpreter attached to a console using parent namesepace.

Parameters:

console - read only collection of input output streams.

parent - interpreter or null.

Interpreter

public Interpreter(ConsoleInterface console,
                   NameSpace globalNameSpace)

An interactive interpreter attached to a console with supplied namespace.

Parameters:

console - read only collection of input output streams.

namespace - global name space or null.

Interpreter

public Interpreter(ConsoleInterface console)

An interactive interpreter attached to a console, no namespace or parent.

Parameters:

console - read only collection of input output streams.

Interpreter

public Interpreter()

A non interactive interpreter for evaluation purposes only. Uses system standard output and error with input deferred to eval.

Interpreter

public Interpreter(NameSpace namespace)

A non interactive interpreter for namespace. Uses system standard output and error with input deferred to eval.

Parameters:

namespace - global name space.

Interpreter

public Interpreter(NameSpace namespace,
                   java.lang.String sourceFileInfo)

A non interactive interpreter for namespace and source file. Uses system standard output and error with input deferred to eval.

Parameters:

namespace - global name space.

sourceFileInfo - source file info for debugging.

Interpreter

public Interpreter(NameSpace namespace,
                   Interpreter parent)

A non interactive interpreter for namespace and parent. Uses system standard output and error with input deferred to eval.

Parameters:

namespace - global name space.

parent - interpreter.

Interpreter

public Interpreter(NameSpace namespace,
                   Interpreter parent,
                   java.lang.String sourceFileInfo)

A non interactive interpreter for namespace, parent and source file. Uses system standard output and error with input deferred to eval.

Parameters:

namespace - global name space.

parent - interpreter.

sourceFileInfo - source file info for debugging.

Interpreter

public Interpreter(Interpreter parent)

Extend existing interpreter.

Parameters:

parent - interpreter.

Method Detail

setShutdownOnExit

public static void setShutdownOnExit(boolean value)

Shared system object visible under bsh.system

setConsole

public void setConsole(ConsoleAssignable console)

Attach an assignable console and initialize a new parser.

Parameters:

console - assignable collection of input output streams.

setConsole

public void setConsole(ConsoleInterface console)

Overloaded to accept a read only console.

Parameters:

console - read only collection of input output streams.

setNameSpace

public void setNameSpace(NameSpace namespace)

Assign the global namespace for this interpreter.

Note: It is preferred to keep the interpreter as long reference and use it to create discardable instances which can inherit from the parent and be dereferenced for collection. This method is only here for completeness.

The global namespace can be accessed in scripts using the variable 'this.namespace' or global.namespace as necessary.

Parameters:

namespace - global name space.

getNameSpace

public NameSpace getNameSpace()

Retrieve the global namespace for this interpreter.

Note: It is preferred to keep the interpreter as long reference and use it to create discardable instances which can inherit from the parent and be dereferenced for collection. This method is only here for completeness.

The global namespace can be accessed in scripts using the variable 'this.namespace' or global.namespace as necessary.

main

public static void main(java.lang.String[] args)

Interactive interpreter command line execution.

Parameters:

args - optional file name for interpretation.

invokeMain

public static void invokeMain(java.lang.Class<?> clas,
                              java.lang.String[] args)
                       throws java.lang.Exception

Convenience method for invoking the main method of a class.

Parameters:

clas - with static main method.

args - the string arguments.

Throws:

java.lang.Exception - thrown if something fails.

run

public void run()

Run interactively. (printing prompts, etc.)

Specified by:

run in interface java.lang.Runnable

source

public java.lang.Object source(java.net.URL url,
                               NameSpace namespace)
                        throws EvalError,
                               java.io.IOException

Source a script from a url for interpretation.

Parameters:

url - the source url.

namespace - effective namespace.

Returns:

the return result from the script execution.

Throws:

EvalError - if a script error occurred.

java.io.IOException - if a file read error occurred.

source

public java.lang.Object source(java.io.File file,
                               NameSpace namespace)
                        throws EvalError,
                               java.io.IOException

Source a script from a file for interpretation.

Parameters:

file - the source file.

namespace - effective namespace.

Returns:

the return result from the script execution.

Throws:

EvalError - if a script error occurred.

java.io.IOException - if a file read error occurred.

source

public java.lang.Object source(java.lang.String filename,
                               NameSpace namespace)
                        throws EvalError,
                               java.io.IOException

Source a script from a filename for interpretation.

Parameters:

filename - the source file name.

namespace - effective namespace.

Returns:

the return result from the script execution.

Throws:

EvalError - if a script error occurred.

java.io.IOException - if a file read error occurred.

source

public java.lang.Object source(java.net.URL url)
                        throws EvalError,
                               java.io.IOException

Source a script from a url for interpretation.

Parameters:

url - the source url.

Returns:

the return result from the script execution.

Throws:

EvalError - if a script error occurred.

java.io.IOException - if a file read error occurred.

source

public java.lang.Object source(java.io.File file)
                        throws EvalError,
                               java.io.IOException

Source a script from a file for interpretation.

Parameters:

file - the source file.

Returns:

the return result from the script execution.

Throws:

EvalError - if a script error occurred.

java.io.IOException - if a file read error occurred.

source

public java.lang.Object source(java.lang.String filename)
                        throws EvalError,
                               java.io.IOException

Source a script from a filename for interpretation.

Parameters:

filename - the source file name.

Returns:

the return result from the script execution.

Throws:

EvalError - if a script error occurred.

java.io.IOException - if a file read error occurred.

eval

public java.lang.Object eval(java.io.Reader in,
                             NameSpace nameSpace,
                             java.lang.String sourceFileInfo)
                      throws EvalError

Spawn a non-interactive local interpreter to evaluate text in the specified namespace. Return value is the evaluated object (or corresponding primitive wrapper).

Parameters:

sourceFileInfo - is for information purposes only. It is used to display error messages (and in the future may be made available to the script).

Throws:

EvalError - on script problems

TargetError - on unhandled exceptions from the script

reset

public void reset()

Optional method to release additional resources. The interpreter allows for multiple eval calls and therefor maintains certain state for subsequent calls. Only use this if completely done with current interpreter and desperate to clear as much resources as possible.

eval

public java.lang.Object eval(java.io.Reader in)
                      throws EvalError

Evaluate the inputstream in this interpreter's global namespace.

Throws:

EvalError

eval

public java.lang.Object eval(java.lang.String statements)
                      throws EvalError

Evaluate the string in this interpreter's global namespace.

Throws:

EvalError

eval

public java.lang.Object eval(java.lang.String statements,
                             NameSpace nameSpace)
                      throws EvalError

Evaluate the string in the specified namespace.

Throws:

EvalError

getIn

public java.io.Reader getIn()

Console delegate methods.

getOut

public java.io.PrintStream getOut()

getErr

public java.io.PrintStream getErr()

println

public final void println(java.lang.Object o)

print

public final void print(java.lang.Object o)

error

public final void error(java.lang.Object o)

setIn

public void setIn(java.io.Reader in)

setOut

public void setOut(java.io.PrintStream out)

setErr

public void setErr(java.io.PrintStream err)

debug

public static final void debug(java.lang.Object... msg)

Print a debug message on debug stream associated with this interpreter only if debugging is turned on.

get

public java.lang.Object get(java.lang.String name)
                     throws EvalError

Get the value of the name. name may be any value. e.g. a variable or field

Throws:

EvalError

set

public void set(java.lang.String name,
                java.lang.Object value)
         throws EvalError

Assign the value to the name. name may evaluate to anything assignable. e.g. a variable or field.

Throws:

EvalError

set

public void set(java.lang.String name,
                long value)
         throws EvalError

Throws:

EvalError

set

public void set(java.lang.String name,
                int value)
         throws EvalError

Throws:

EvalError

set

public void set(java.lang.String name,
                double value)
         throws EvalError

Throws:

EvalError

set

public void set(java.lang.String name,
                float value)
         throws EvalError

Throws:

EvalError

set

public void set(java.lang.String name,
                boolean value)
         throws EvalError

Throws:

EvalError

unset

public void unset(java.lang.String name)
           throws EvalError

Unassign the variable name. Name should evaluate to a variable.

Throws:

EvalError

getInterface

public java.lang.Object getInterface(java.lang.Class<?> interf)
                              throws EvalError

Get a reference to the interpreter (global namespace), cast to the specified interface type. Assuming the appropriate methods of the interface are defined in the interpreter, then you may use this interface from Java, just like any other Java object.

For example:

            Interpreter interpreter = new Interpreter();
            // define a method called run()
            interpreter.eval("run() { ... }");

            // Fetch a reference to the interpreter as a Runnable
            Runnable runnable =
                (Runnable)interpreter.getInterface( Runnable.class );
        

Note that the interpreter does *not* require that any or all of the methods of the interface be defined at the time the interface is generated. However if you attempt to invoke one that is not defined you will get a runtime exception.

Note also that this convenience method has exactly the same effect as evaluating the script:

            (Type)this;
        

For example, the following is identical to the previous example:

            // Fetch a reference to the interpreter as a Runnable
            Runnable runnable =
                (Runnable)interpreter.eval( "(Runnable)this" );
        

Version requirement Although standard Java interface types are always available, to be used with arbitrary interfaces this feature requires that you are using Java 1.3 or greater.

Throws:

EvalError - if the interface cannot be generated because the version of Java does not support the proxy mechanism.

setYieldDelay

public void setYieldDelay(int delay)

Set thread yield delay time in milliseconds. How long to wait for closing thread @see yield();

Parameters:

delay - sleep time in milliseconds

pathToFile

public java.io.File pathToFile(java.lang.String fileName)
                        throws java.io.IOException

Localize a path to the file name based on the bsh.cwd interpreter working directory.

Throws:

java.io.IOException

redirectOutputToFile

@Deprecated
public static void redirectOutputToFile(java.lang.String filename)

Deprecated. redirects global JVM streams rather than any specific interpreter's own streams. Use setOutputFile(String) to redirect a particular interpreter's output.

Redirect the JVM-wide System.out / System.err to a file. This does not affect any particular Interpreter instance's own output (see getOut()); despite its name and signature it is unrelated to a specific interpreter.

Parameters:

filename - file to write output to.

setOutputFile

public void setOutputFile(java.lang.String filename)

Redirect this interpreter's own output and error streams to a file, leaving System.out / System.err untouched.

Parameters:

filename - file to write output to.

setClassLoader

public void setClassLoader(java.lang.ClassLoader externalCL)

Set an external class loader to be used as the base classloader for BeanShell. The base classloader is used for all classloading unless/until the addClasspath()/setClasspath()/reloadClasses() commands are called to modify the interpreter's classpath. At that time the new paths /updated paths are added on top of the base classloader.

BeanShell will use this at the same point it would otherwise use the plain Class.forName(). i.e. if no explicit classpath management is done from the script (addClassPath(), setClassPath(), reloadClasses()) then BeanShell will only use the supplied classloader. If additional classpath management is done then BeanShell will perform that in addition to the supplied external classloader. However BeanShell is not currently able to reload classes supplied through the external classloader.

See Also:

BshClassManager.setClassLoader( ClassLoader )

getClassManager

public BshClassManager getClassManager()

Get the class manager associated with this interpreter (the BshClassManager of this interpreter's global namespace). This is primarily a convenience method.

setStrictJava

public void setStrictJava(boolean b)

Set strict Java mode on or off. This mode attempts to make BeanShell syntax behave as Java syntax, eliminating conveniences like loose variables, etc. When enabled, variables are required to be declared or initialized before use and method arguments are reqired to have types.

This mode will become more strict in a future release when classes are interpreted and there is an alternative to scripting objects as method closures.

getStrictJava

public boolean getStrictJava()

See Also:

setStrictJava( boolean )

getSourceFileInfo

public java.lang.String getSourceFileInfo()

Specify the source of the text from which this interpreter is reading. Note: there is a difference between what file the interrpeter is sourcing and from what file a method was originally parsed. One file may call a method sourced from another file. See Node for origination file info.

See Also:

Node.getSourceFile()

getParent

public Interpreter getParent()

Get the parent Interpreter of this interpreter, if any. Currently this relationship implies the following: 1) Parent and child share a BshClassManager 2) Children indicate the parent's source file information in error reporting. When created as part of a source() / eval() the child also shares the parent's namespace. But that is not necessary in general.

setExitOnEOF

public void setExitOnEOF(boolean value)

Specify whether, in interactive mode, the interpreter exits Java upon end of input. If true, when in interactive mode the interpreter will issue a System.exit(0) upon eof. If false the interpreter no System.exit() will be done.

Note: if you wish to cause an EOF externally you can try closing the input stream. This is not guaranteed to work in older versions of Java due to Java limitations, but should work in newer JDK/JREs. (That was the motivation for the Java NIO package).

setShowResults

public void setShowResults(boolean showResults)

Turn on/off the verbose printing of results as for the show() command. If this interpreter has a parent the call is delegated. See the BeanShell show() command.

getShowResults

public boolean getShowResults()

Show on/off verbose printing status for the show() command. See the BeanShell show() command. If this interpreter has a parent the call is delegated.

getCompatibility

public boolean getCompatibility()

Compatibility mode. When true missing classes are tried to create from corresponding java source files. The Default value is false. This could be changed to true by setting the system property "bsh.compatibility" to "true".

See Also:

setCompatibility(boolean)

setCompatibility

public void setCompatibility(boolean value)

Setting compatibility mode. When true missing classes are tried to create from corresponding java source files. The Default value is false. This could be changed to true by setting the system property "bsh.compatibility" to "true".

See Also:

getCompatibility()

getSaveClassesDir

public static java.lang.String getSaveClassesDir()

getSaveClasses

public static boolean getSaveClasses()

classLoaderChanged

public void classLoaderChanged()

Specified by:

classLoaderChanged in interface BshClassManager.Listener