net.sf.saxon.expr.instruct
Class SlotManager

java.lang.Object
  net.sf.saxon.expr.instruct.SlotManager

All Implemented Interfaces:

Serializable

public class SlotManager
extends Object
implements Serializable

A SlotManager supports functions, templates, etc: specifically, any executable code that requires a stack frame containing local variables. In XSLT a SlotManager underpins any top-level element that can contain local variable declarations, specifically, a top-level xsl:template, xsl:variable, xsl:param, or xsl:function element or an xsl:attribute-set element or xsl:key element. In XQuery it underpins functions and global variables. The purpose of the SlotManager is to allocate slot numbers to variables in the stack, and to record how many slots are needed. A Debugger may define a subclass with additional functionality.

See Also:

Serialized Form

Field Summary

static SlotManager

EMPTY An empty SlotManager

Constructor Summary

SlotManager()
The constructor should not be called directly.

SlotManager(int n)
Create a SlotManager with a given number of slots

Method Summary

int	allocateSlotNumber(StructuredQName qName) Allocate a slot number for a variable
int	getNumberOfVariables() Get number of variables (size of stack frame)
List<StructuredQName>	getVariableMap() Get the variable map (simply a list of variable names as structured QNames).
void	setNumberOfVariables(int numberOfVariables) Set the number of variables

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY

public static SlotManager EMPTY

An empty SlotManager

Constructor Detail

SlotManager

public SlotManager()

The constructor should not be called directly. A new SlotManager should be obtained using the factory method Configuration.makeSlotManager().

SlotManager

public SlotManager(int n)

Create a SlotManager with a given number of slots

Parameters:

n - the number of slots

Method Detail

getNumberOfVariables

public int getNumberOfVariables()

Get number of variables (size of stack frame)

Returns:

the number of slots for variables

setNumberOfVariables

public void setNumberOfVariables(int numberOfVariables)

Set the number of variables

Parameters:

numberOfVariables - the space to be allocated for variables

allocateSlotNumber

public int allocateSlotNumber(StructuredQName qName)

Allocate a slot number for a variable

Parameters:

qName - the name of the variable

Returns:

the allocated slot number (the next one available)

getVariableMap

public List<StructuredQName> getVariableMap()

Get the variable map (simply a list of variable names as structured QNames). Note that it is possible for several variables to have the same name.

Changed in Saxon 9.0 to return a list of StructuredQName values rather than integers

Returns:

the list of variable names for this stack frame