Package org.basex.query.var

Class QueryStack

java.lang.Object

org.basex.query.var.QueryStack

public final class QueryStack
extends Object

The query stack, containing local variable bindings of all active scopes.

Author:

BaseX Team 2005-21, BSD License, Leo Woerteler

Constructor Summary

Constructors

Constructor	Description
QueryStack()

Method Summary

Modifier and Type	Method	Description
String	dump()	Creates a dump of the current variable stack.
int	enterFrame(int size)	Enters a new stack frame.
void	exitFrame(int frame)	Exits a stack frame and makes all bound variables eligible for garbage collection.
Value	get(Var var)	Gets the value bound to the given variable in the current stack frame.
void	reuseFrame(int size)	Prepares the current stack frame to be reused.
void	set(Var var, Value value, QueryContext qc)	Sets the value of the given variable in the current stack frame.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Details

QueryStack

public QueryStack()

Method Details

enterFrame

public int enterFrame(int size)

Enters a new stack frame.

Parameters:

size - size of this frame

Returns:

stack pointer of the old frame

reuseFrame

public void reuseFrame(int size)

Prepares the current stack frame to be reused.

Parameters:

size - new frame size

exitFrame

public void exitFrame(int frame)

Exits a stack frame and makes all bound variables eligible for garbage collection.

Parameters:

frame - frame pointer of the underlying stack frame

get

public Value get(Var var)

Gets the value bound to the given variable in the current stack frame.

Parameters:

var - variable

Returns:

bound value

set

public void set(Var var,
 Value value,
 QueryContext qc)
         throws QueryException

Sets the value of the given variable in the current stack frame.

Parameters:

var - variable to bind the value to

value - value to bind

qc - query context

Throws:

QueryException - if the value does not have the right type

dump

public String dump()

Creates a dump of the current variable stack.

Returns:

string dump

toString

public String toString()

Overrides:

toString in class Object