Package net.sf.saxon.expr.instruct

Class NamespaceConstructor

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.instruct.Instruction
net.sf.saxon.expr.instruct.SimpleNodeConstructor
net.sf.saxon.expr.instruct.NamespaceConstructor
All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, TailCallReturner, InstructionInfo, Locator
public class NamespaceConstructor extends SimpleNodeConstructor
A namespace constructor instruction. (xsl:namespace in XSLT 2.0, or namespace{}{} in XQuery 1.1)
See Also:

  • Constructor Details

    • NamespaceConstructor

      public NamespaceConstructor(Expression name)
      Create an xsl:namespace instruction for dynamic construction of namespace nodes
      Parameters:
      name - the expression to evaluate the name of the node (that is, the prefix)

  • Method Details

    • getNameExpression

      public Expression getNameExpression()
      Get the expression that defines the namespace node's name
      Returns:
      the expression that defines the namespace node's name (that is, the namespace prefix)

    • getInstructionNameCode

      public int getInstructionNameCode()
      Set the name of this instruction for diagnostic and tracing purposes
      Overrides:
      getInstructionNameCode in class Instruction
      Returns:
      a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace

    • simplify

      public Expression simplify(ExpressionVisitor visitor) throws XPathException
      Description copied from class: Instruction
      Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.
      Overrides:
      simplify in class SimpleNodeConstructor
      Parameters:
      visitor - an expression visitor
      Returns:
      the simplified expression
      Throws:
      XPathException - if an error is discovered during expression rewriting

    • getItemType

      public ItemType getItemType(TypeHierarchy th)
      Description copied from class: Instruction
      Get the item type of the items returned by evaluating this instruction
      Overrides:
      getItemType in class Instruction
      Parameters:
      th - the type hierarchy cache
      Returns:
      the static item type of the instruction

    • getCardinality

      public int getCardinality()
      Description copied from class: Expression
      Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.
      Overrides:
      getCardinality in class Expression
      Returns:
      one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).

    • promoteInst

      protected void promoteInst(PromotionOffer offer) throws XPathException
      Description copied from class: SimpleNodeConstructor
      Offer promotion for subexpressions. The offer will be accepted if the subexpression is not dependent on the factors (e.g. the context item) identified in the PromotionOffer. By default the offer is not accepted - this is appropriate in the case of simple expressions such as constant values and variable references where promotion would give no performance advantage. This method is always called at compile time.
      Overrides:
      promoteInst in class SimpleNodeConstructor
      Parameters:
      offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
      Throws:
      XPathException - if any error is detected

    • localTypeCheck

      public void localTypeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
      Description copied from class: SimpleNodeConstructor
      Method to perform type-checking specific to the kind of instruction
      Specified by:
      localTypeCheck in class SimpleNodeConstructor
      Parameters:
      visitor - an expression visitor
      contextItemType - the static type of the context item
      Throws:
      XPathException - if a type error is detected

    • iterateSubExpressions

      public Iterator<Expression> iterateSubExpressions()
      Description copied from class: Expression
      Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.
      Overrides:
      iterateSubExpressions in class SimpleNodeConstructor
      Returns:
      an iterator containing the sub-expressions of this expression

    • copy

      public Expression copy()
      Copy an expression. This makes a deep copy.
      Specified by:
      copy in class Expression
      Returns:
      the copy of the original expression

    • replaceSubExpression

      public boolean replaceSubExpression(Expression original, Expression replacement)
      Replace one subexpression by a replacement subexpression
      Overrides:
      replaceSubExpression in class SimpleNodeConstructor
      Parameters:
      original - the original subexpression
      replacement - the replacement subexpression
      Returns:
      true if the original subexpression is found

    • evaluateNodeName

      public NodeName evaluateNodeName(XPathContext context) throws XPathException
      Description copied from class: SimpleNodeConstructor
      Run-time method to compute the name of the node being constructed. This is overridden for nodes that have a name. The default implementation returns -1, which is suitable for unnamed nodes such as comments
      Overrides:
      evaluateNodeName in class SimpleNodeConstructor
      Parameters:
      context - the XPath dynamic evaluation context
      Returns:
      the name pool nameCode identifying the name of the constructed node
      Throws:
      XPathException - if any failure occurs

    • processValue

      public void processValue(CharSequence value, XPathContext context) throws XPathException
      Description copied from class: SimpleNodeConstructor
      Process the value of the node, to create the new node.
      Specified by:
      processValue in class SimpleNodeConstructor
      Parameters:
      value - the string value of the new node
      context - the dynamic evaluation context
      Throws:
      XPathException - if a dynamic error occurs

    • evaluateItem

      public NodeInfo evaluateItem(XPathContext context) throws XPathException
      Evaluate as an expression. We rely on the fact that when these instructions are generated by XQuery, there will always be a valueExpression to evaluate the content
      Overrides:
      evaluateItem in class SimpleNodeConstructor
      Parameters:
      context - The context in which the expression is to be evaluated
      Returns:
      the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression

    • explain

      public void explain(ExpressionPresenter out)
      Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
      Specified by:
      explain in class Expression
      Parameters:
      out - the expression presenter used to display the structure