Package net.sf.saxon.expr.instruct

Class SlotManager

java.lang.Object
net.sf.saxon.expr.instruct.SlotManager
Direct Known Subclasses:
SlotManagerEE
public class SlotManager extends Object
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.

  • Field Details

    • EMPTY

      public static SlotManager EMPTY
      An empty SlotManager

  • Constructor Details

    • 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 Details

    • 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, LocalBinding binding)
      Allocate a slot number for a variable
      Parameters:
      qName - the name of the variable
      binding - the binding of the variable (only used in Saxon-EE)
      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.
      Returns:
      the list of variable names for this stack frame

    • showStackFrame

      public void showStackFrame(XPathContext context, Logger logger)
      Display the values of the variables and parameters in an XPathContext stack frame to a Logger
      Parameters:
      context - the XPathContext holding the stack frame
      logger - the destination for the output