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 the interface.
 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 from outside java code, using the declaring interpreter and current namespace.
 java.lang.Object invokeMethod(java.lang.String name, java.lang.Object[] args, Interpreter interpreter, CallStack callstack, SimpleNode callerInfo)
          Invoke specified method with specified interpreter.
(package private)  CallStack newCallStack()
          Remove a This reference from a parent's namespace.
 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 EvalError
Get a version of the interface. If this type of This implements it directly return this, else try complain that we don't have the proxy mechanism.

EvalError

getNameSpace

public NameSpace getNameSpace()

toString

public java.lang.String toString()
Overrides:
toString in class java.lang.Object

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 from outside java code, using the declaring interpreter and current namespace. The call stack will appear as if the method is being invoked from outside of bsh in native java code.

EvalError

invokeMethod

public java.lang.Object invokeMethod(java.lang.String name,
                                     java.lang.Object[] args,
                                     Interpreter interpreter,
                                     CallStack callstack,
                                     SimpleNode callerInfo)
                              throws EvalError
Invoke specified method with specified interpreter. This is simply a convenience method.

EvalError

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)


newCallStack

CallStack newCallStack()
Remove a This reference from a parent's namespace. It's necessary to unbind a This reference before serialization if you don't want serialization to save the entire interpreter and all enclosing namespaces. This is used by the bsh save() 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) public static void unbind( This ths ) { }