Package net.sf.saxon.expr.flwor

Class Clause

java.lang.Object
net.sf.saxon.expr.flwor.Clause
Direct Known Subclasses:
CountClause, DiagnosticClause, ForClause, GroupByClause, LetClause, OrderByClause, TraceClause, WhereClause, WhileClause, WindowClause
public abstract class Clause extends Object
A "Clause" refers specifically to one of the clauses of a FLWOR expression, for example the "for" clause, the "let" clause, the "where" or "order by" clause. (The "return" clause, however, is not modelled as a Clause).

  • Constructor Details

    • Clause

      public Clause()

  • Method Details

    • getLocation

      public Location getLocation()
      Get the location, which can be used to determine the system ID and line number of the clause
      Returns:
      the location, or Loc.NONE if not known

    • setLocation

      public void setLocation(Location locationId)
      Set the location, which can be used to determine the system ID and line number of the clause
      Parameters:
      locationId - the location

    • setPackageData

      public void setPackageData(PackageData pd)

    • getPackageData

      public PackageData getPackageData()

    • getConfiguration

      public Configuration getConfiguration()

    • setRepeated

      public void setRepeated(boolean repeated)

    • isRepeated

      public boolean isRepeated()

    • copy

      public abstract Clause copy(FLWORExpression flwor, RebindingMap rebindings)
      Create a copy of this 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

    • optimize

      public void optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException
      Optimize any expressions contained within this clause
      Parameters:
      visitor - the ExpressionVisitor, providing access to static context information
      contextItemType - the type of the context item
      Throws:
      XPathException - if any error is detected

    • typeCheck

      public void typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
      Type-check any expression contained within this 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 abstract TuplePull getPullStream(TuplePull base, XPathContext context)
      Get a pull-mode tuple stream that implements the functionality of this clause, taking its input from another tuple stream which this clause modifies
      Parameters:
      base - the input tuple stream
      context - the dynamic evaluation context
      Returns:
      the output tuple stream

    • getPushStream

      public abstract 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
      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

    • processOperands

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

    • explain

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

    • getRangeVariables

      public LocalVariableBinding[] getRangeVariables()
      Get the variables bound by this clause
      Returns:
      the variable bindings

    • gatherVariableReferences

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

    • containsNonInlineableVariableReference

      public boolean containsNonInlineableVariableReference(Binding binding)
      Determine whether the clause contains a reference to a local variable binding that cannot be inlined
      Parameters:
      binding - the binding for the local variable in question
      Returns:
      true if this clause uses the variable in a way that does not permit inlining

    • refineVariableType

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

    • addToPathMap

      public abstract void addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
      Collect information about the navigation paths followed by this clause, for document projection purposes
      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

    • getClauseKey

      public abstract Clause.ClauseName getClauseKey()
      Get a keyword identifying what kind of clause this is
      Returns:
      the kind of clause

    • toShortString

      public String toShortString()
      Get a short string representation of the clause
      Returns:
      a recognizable string

    • getTraceInfo

      public Map<String,Object> getTraceInfo()
      Get information for inclusion in trace output
      Returns:
      a map containing the properties to be output