Package net.sf.saxon.expr.flwor

Class ForClause

java.lang.Object
net.sf.saxon.expr.flwor.Clause
net.sf.saxon.expr.flwor.ForClause
public class ForClause extends Clause
A "for" clause in a FLWOR expression

  • Field Details

  • Constructor Details

    • ForClause

      public ForClause()

  • Method Details

    • getClauseKey

      public Clause.ClauseName getClauseKey()
      Description copied from class: Clause
      Get a keyword identifying what kind of clause this is
      Specified by:
      getClauseKey in class Clause
      Returns:
      the kind of clause

    • copy

      public ForClause copy(FLWORExpression flwor, RebindingMap rebindings)
      Description copied from class: Clause
      Create a copy of this clause
      Specified by:
      copy in class Clause
      Parameters:
      flwor - the new FLWORExpression to contain the copied clause. Note that this will not have been fully initialized.
      rebindings - the rebinding map
      Returns:
      the copied clause

    • initSequence

      public void initSequence(FLWORExpression flwor, Expression sequence)

    • setSequence

      public void setSequence(Expression sequence)

    • getSequence

      public Expression getSequence()

    • getSequenceOp

      public Operand getSequenceOp()

    • getIterator

      protected SequenceIterator getIterator(XPathContext context) throws XPathException
      Get an iterator over the items or members in the input sequence.
      Parameters:
      context - dynamic evaluation context
      Returns:
      for a simple "for $x" clause, the sequence of items to which $x will be bound. For a "for member ¢x" clause, the sequence of array members, each wrapped as an object value
      Throws:
      XPathException - if evaluation fails

    • setRangeVariable

      public void setRangeVariable(LocalVariableBinding binding)
      Set the range variable (the primary variable bound by this clause)
      Parameters:
      binding - the range variable

    • getRangeVariable

      public LocalVariableBinding getRangeVariable()
      Get the range variable (the primary variable bound by this clause)
      Returns:
      the range variable

    • setPositionVariable

      public void setPositionVariable(LocalVariableBinding binding)
      Set the position variable (the variable bound by the "at" clause)
      Parameters:
      binding - the position variable, or null if there is no position variable

    • getPositionVariable

      public LocalVariableBinding getPositionVariable()
      Get the position variable (the variable bound by the "at" clause)
      Returns:
      the position variable, or null if there is no position variable

    • getRangeVariables

      public LocalVariableBinding[] getRangeVariables()
      Get the variables bound by this clause
      Overrides:
      getRangeVariables in class Clause
      Returns:
      the variable bindings (1 or 2 depending on whether there is a position variable)

    • setAllowingEmpty

      public void setAllowingEmpty(boolean option)
      Say whether the "allowing empty" option is present
      Parameters:
      option - true if the "allowing empty" option is present

    • isAllowingEmpty

      public boolean isAllowingEmpty()
      Ask whether the "allowing empty" option is present
      Returns:
      true if the "allowing empty" option is present

    • typeCheck

      public void typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
      Type-check the expression
      Overrides:
      typeCheck in class Clause
      Parameters:
      visitor - the ExpressionVisitor, providing access to static context information
      contextInfo - static information about the dynamic context
      Throws:
      XPathException - if any error is detected

    • getPullStream

      public TuplePull getPullStream(TuplePull base, XPathContext context)
      Get a tuple stream that implements the functionality of this clause, taking its input from another tuple stream which this clause modifies
      Specified by:
      getPullStream in class Clause
      Parameters:
      base - the input tuple stream
      context - the XPath dynamic context
      Returns:
      the output tuple stream

    • getPushStream

      public TuplePush getPushStream(TuplePush destination, Outputter output, XPathContext context)
      Get a push-mode tuple stream that implements the functionality of this clause, supplying its output to another tuple stream
      Specified by:
      getPushStream in class Clause
      Parameters:
      destination - the output tuple stream
      output - the destination for the result
      context - the dynamic evaluation context
      Returns:
      the push tuple stream that implements the functionality of this clause of the FLWOR expression

    • addPredicate

      public boolean addPredicate(FLWORExpression flwor, ExpressionVisitor visitor, ContextItemStaticInfo contextItemType, Expression condition) throws XPathException
      Convert where clause to a predicate.
      Parameters:
      flwor - the FLWOR expression (sans the relevant part of the where clause)
      visitor - the expression visitor
      contextItemType - the item type of the context item
      condition - the predicate to be added. This will always be a single term (never a composite condition using "and"), as the where clause is split into separate terms before calling this method
      Returns:
      true if the expression has been changed, that is, if the where clause has been converted
      Throws:
      XPathException - if an error is encountered

    • processOperands

      public void processOperands(OperandProcessor processor) throws XPathException
      Process the subexpressions of this clause
      Specified by:
      processOperands in class Clause
      Parameters:
      processor - the expression processor used to process the subexpressions
      Throws:
      XPathException - if any error is detected

    • gatherVariableReferences

      public void gatherVariableReferences(ExpressionVisitor visitor, Binding binding, List<VariableReference> references)
      Description copied from class: Clause
      Build a list of all references to a variables declared in this clause
      Overrides:
      gatherVariableReferences in class Clause
      Parameters:
      visitor - the expression visitor
      binding - a variable declared in this clause
      references - the list of variable references, initially empty, to which the method will append

    • refineVariableType

      public void refineVariableType(ExpressionVisitor visitor, List<VariableReference> references, Expression returnExpr)
      Description copied from class: Clause
      Supply improved type information to the expressions that contain references to the variables declared in this clause
      Overrides:
      refineVariableType in class Clause
      Parameters:
      visitor - the expression visitor
      references - the list of variable references
      returnExpr - the expression in the return clause

    • addToPathMap

      public void addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
      Description copied from class: Clause
      Collect information about the navigation paths followed by this clause, for document projection purposes
      Specified by:
      addToPathMap in class Clause
      Parameters:
      pathMap - the path map in which the data is to be collected
      pathMapNodeSet - the path map node set representing the paths to the context item

    • explain

      public void explain(ExpressionPresenter out) throws XPathException
      Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
      Specified by:
      explain in class Clause
      Parameters:
      out - the expression presenter used to display the structure
      Throws:
      XPathException - if any error occurs

    • toShortString

      public String toShortString()
      Description copied from class: Clause
      Get a short string representation of the clause
      Overrides:
      toShortString in class Clause
      Returns:
      a recognizable string

    • toString

      public String toString()
      Overrides:
      toString in class Object