bsh
Class This

java.lang.Object
  bsh.This

All Implemented Interfaces:

java.lang.Runnable, java.io.Serializable

Direct Known Subclasses:

JThis, XThis

public class This

extends java.lang.Object

implements java.io.Serializable, java.lang.Runnable

'This' is the type of bsh scripted objects. A 'This' object is a bsh scripted object context. It holds a namespace reference and implements event listeners and various other interfaces. This holds a reference to the declaring interpreter for callbacks from outside of bsh.

See Also:

Serialized Form

Field Summary

(package private) Interpreter	declaringInterpreter This is the interpreter running when the This ref was created.
(package private) NameSpace	namespace The namespace that this This reference wraps.

Constructor Summary

protected

This(NameSpace namespace, Interpreter declaringInterpreter)

Method Summary

static void	bind(This ths, NameSpace namespace, Interpreter declaringInterpreter) Bind a This reference to a parent's namespace with the specified declaring interpreter.
java.lang.Object	getInterface(java.lang.Class clas) Get a version of this scripted object implementing the specified interface.
java.lang.Object	getInterface(java.lang.Class[] ca) Get a version of this scripted object implementing the specified interfaces.
NameSpace	getNameSpace()
(package private) static This	getThis(NameSpace namespace, Interpreter declaringInterpreter) getThis() is a factory for bsh.This type references.
java.lang.Object	invokeMethod(java.lang.String name, java.lang.Object[] args) Invoke specified method as from outside java code, using the declaring interpreter and current namespace.
java.lang.Object	invokeMethod(java.lang.String methodName, java.lang.Object[] args, Interpreter interpreter, CallStack callstack, SimpleNode callerInfo, boolean declaredOnly) Invoke a method in this namespace with the specified args, interpreter reference, callstack, and caller info.
(package private) static boolean	isExposedThisMethod(java.lang.String name) Allow invocations of these method names on This type objects.
void	run()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

namespace

NameSpace namespace

The namespace that this This reference wraps.

declaringInterpreter

transient Interpreter declaringInterpreter

This is the interpreter running when the This ref was created. It's used as a default interpreter for callback through the This where there is no current interpreter instance e.g. interface proxy or event call backs from outside of bsh.

Constructor Detail

This

protected This(NameSpace namespace,
               Interpreter declaringInterpreter)

Method Detail

getThis

static This getThis(NameSpace namespace,
                    Interpreter declaringInterpreter)

getThis() is a factory for bsh.This type references. The capabilities of ".this" references in bsh are version dependent up until jdk1.3. The version dependence was to support different default interface implementations. i.e. different sets of listener interfaces which scripted objects were capable of implementing. In jdk1.3 the reflection proxy mechanism was introduced which allowed us to implement arbitrary interfaces. This is fantastic. A This object is a thin layer over a namespace, comprising a bsh object context. We create it here only if needed for the namespace. Note: this method could be considered slow because of the way it dynamically factories objects. However I've also done tests where I hard-code the factory to return JThis and see no change in the rough test suite time. This references are also cached in NameSpace.

getInterface

public java.lang.Object getInterface(java.lang.Class clas)
                              throws UtilEvalError

Get a version of this scripted object implementing the specified interface.

Throws:

UtilEvalError

getInterface

public java.lang.Object getInterface(java.lang.Class[] ca)
                              throws UtilEvalError

Get a version of this scripted object implementing the specified interfaces.

Throws:

UtilEvalError

getNameSpace

public NameSpace getNameSpace()

toString

public java.lang.String toString()

run

public void run()

Specified by:

run in interface java.lang.Runnable

invokeMethod

public java.lang.Object invokeMethod(java.lang.String name,
                                     java.lang.Object[] args)
                              throws EvalError

Invoke specified method as from outside java code, using the declaring interpreter and current namespace. The call stack will indicate that the method is being invoked from outside of bsh in native java code. Note: you must still wrap/unwrap args/return values using Primitive/Primitive.unwrap() for use outside of BeanShell.

Throws:

EvalError

See Also:

Primitive

invokeMethod

public java.lang.Object invokeMethod(java.lang.String methodName,
                                     java.lang.Object[] args,
                                     Interpreter interpreter,
                                     CallStack callstack,
                                     SimpleNode callerInfo,
                                     boolean declaredOnly)
                              throws EvalError

Invoke a method in this namespace with the specified args, interpreter reference, callstack, and caller info.

Note: If you use this method outside of the bsh package and wish to use variables with primitive values you will have to wrap them using bsh.Primitive. Consider using This getInterface() to make a true Java interface for invoking your scripted methods.

This method also implements the default object protocol of toString(), hashCode() and equals() and the invoke() meta-method handling as a last resort.

Note: The invoke() meta-method will not catch the Object protocol methods (toString(), hashCode()...). If you want to override them you have to script them directly.

Parameters:

declaredOnly - if true then only methods declared directly in the namespace will be visible - no inherited or imported methods will be visible.

Throws:

EvalError

See Also:

bsh.This.invokeMethod( String methodName, Object [] args, Interpreter interpreter, CallStack callstack, SimpleNode callerInfo ), Primitive

bind

public static void bind(This ths,
                        NameSpace namespace,
                        Interpreter declaringInterpreter)

Bind a This reference to a parent's namespace with the specified declaring interpreter. Also re-init the callstack. It's necessary to bind a This reference before it can be used after deserialization. This is used by the bsh load() command.

This is a static utility method because it's used by a bsh command bind() and the interpreter doesn't currently allow access to direct methods of This objects (small hack)

isExposedThisMethod

static boolean isExposedThisMethod(java.lang.String name)

Allow invocations of these method names on This type objects. Don't give bsh.This a chance to override their behavior.

If the method is passed here the invocation will actually happen on the bsh.This object via the regular reflective method invocation mechanism. If not, then the method is evaluated by bsh.This itself as a scripted method call.