org.concord.util.script
Class NameStack

java.lang.Object
  |
  +--org.concord.util.script.ScriptObject
        |
        +--org.concord.util.script.NameStack

All Implemented Interfaces:

java.beans.BeanInfo

public class NameStack

extends ScriptObject

The NameStack class implements a stack frame mechanism for the script interpreter. It is responsible for storing and finding variables and varible values. Each time a script method is invoked a new NameStack stack frame is created and linked to the previous one. All values calculated by the interpreter are pushed on and popped off the current instance of the NameStack. This makes it easier to provide global, script and method variables scope.

The NameStack consists of two Java Stack objects, one for names and one for values. Name-value pairs can be pushed and popped, and in addition, name lookup and enter methods are provided to make it easy to read and write variable values.

Version:

$Revision: 1.2 $ $Date: 2001/11/08 20:51:36 $

Author:

$Author: ed $

Field Summary

boolean	finished
protected int	frameSize
protected NameStack	globals
protected NameStack	imports
protected static java.lang.String	indent
boolean	isWhen
protected NameStack	members
protected java.util.Stack	names
ScriptObject	node
java.lang.Object	result
boolean	returned
boolean	skipped
boolean	throwUp
protected java.util.Stack	values

Fields inherited from class org.concord.util.script.ScriptObject

beginColumn, beginLine, debug, deleted, doConversion, endColumn, endLine, name, nil, runtimeTable, script

Fields inherited from interface java.beans.BeanInfo

ICON_COLOR_16x16, ICON_COLOR_32x32, ICON_MONO_16x16, ICON_MONO_32x32

Constructor Summary

NameStack()

NameStack(boolean doThrow)

NameStack(NameStack previous)

Method Summary

int	addLocals(java.util.Stack nameStack, java.lang.Object[] args) Add parameters and locals to stack frame.
void	delete()
void	deleteAll()
void	enter(java.lang.String varName, java.lang.Object objValue) Set a variable value in the stack frame.
void	enter(java.lang.String varName, java.lang.Object objValue, boolean doThrow)
NameStack	getGlobals()
NameStack	getImports()
NameStack	getMembers()
java.util.Stack	getNames()
NameStack	getParent() This method is used to pop a stack frame.
int	getSize()
java.util.Stack	getValues()
protected void	init(NameStack previous, boolean doThrow)
java.lang.Object	lookup(java.lang.String varName) Find a variable value in the stack frame.
java.lang.Object	lookup(java.lang.String varName, boolean doThrow)
java.lang.Object	pop()
void	print()
void	push(java.lang.Object objValue)
void	push(java.lang.String varName, java.lang.Object objValue)
boolean	remove(java.lang.String objName)
void	removeLocals(int n)
void	setGlobals(NameStack stack)
void	setImports(NameStack stack)
void	setMembers(NameStack stack)

Methods inherited from class org.concord.util.script.ScriptObject

findConstructor, findMethod, getAdditionalBeanInfo, getArrayValue, getAtom, getBeanDescriptor, getCurrentFrame, getDefaultEventIndex, getDefaultPropertyIndex, getEventSetDescriptors, getField, getFieldValue, getIcon, getMethodDescriptors, getName, getPropertyDescriptors, getScript, interpret, popFrame, pushFrame, setArrayValue, setCurrentFrame, setFieldValue, setName, setScript, setSourceBounds

Methods inherited from class java.lang.Object

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

Field Detail

frameSize

protected int frameSize

globals

protected NameStack globals

members

protected NameStack members

imports

protected NameStack imports

values

protected java.util.Stack values

names

protected java.util.Stack names

indent

protected static java.lang.String indent

skipped

public boolean skipped

finished

public boolean finished

returned

public boolean returned

throwUp

public boolean throwUp

isWhen

public boolean isWhen

result

public java.lang.Object result

node

public ScriptObject node

Constructor Detail

NameStack

public NameStack()

NameStack

public NameStack(boolean doThrow)

NameStack

public NameStack(NameStack previous)

Method Detail

delete

public void delete()

Overrides:

delete in class ScriptObject

deleteAll

public void deleteAll()

init

protected void init(NameStack previous,
                    boolean doThrow)

getNames

public java.util.Stack getNames()

getValues

public java.util.Stack getValues()

lookup

public java.lang.Object lookup(java.lang.String varName)

Find a variable value in the stack frame.

Parameters:

String - varName - name of the variable

Returns:

Object objValue - value of the variable

Throws:

NoSuchElementException - (RuntimeException)

lookup

public java.lang.Object lookup(java.lang.String varName,
                               boolean doThrow)

enter

public void enter(java.lang.String varName,
                  java.lang.Object objValue)

Set a variable value in the stack frame.

Parameters:

String - varName - name of the variable

Object - objValue - value of the variable

Throws:

NoSuchElementException - (RuntimeException)

enter

public void enter(java.lang.String varName,
                  java.lang.Object objValue,
                  boolean doThrow)

addLocals

public int addLocals(java.util.Stack nameStack,
                     java.lang.Object[] args)

Add parameters and locals to stack frame.

This method is used to set up the stack frame context so that the method statements can be interpreted and have access to the parameters and locals.

Parameters:

Stack - parameters - formal parameters name list

Stack - actuals - actual parameters value list

Stack - locals - local variables name list

removeLocals

public void removeLocals(int n)

getParent

public NameStack getParent()

This method is used to pop a stack frame. When a acript method is done it calls this to restore the getCurrentFrame() variable.

getSize

public int getSize()

setMembers

public void setMembers(NameStack stack)

getMembers

public NameStack getMembers()

setGlobals

public void setGlobals(NameStack stack)

getGlobals

public NameStack getGlobals()

setImports

public void setImports(NameStack stack)

getImports

public NameStack getImports()

push

public void push(java.lang.String varName,
                 java.lang.Object objValue)

push

public void push(java.lang.Object objValue)

pop

public java.lang.Object pop()

remove

public boolean remove(java.lang.String objName)

print

public void print()