Class ParentNodeConstructor

All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfo, Locator
Direct Known Subclasses:
DocumentInstr, ElementCreator

public abstract class ParentNodeConstructor extends Instruction
An abstract class to act as a common parent for instructions that create element nodes and document nodes.
See Also:
  • Field Details

  • Constructor Details

    • ParentNodeConstructor

      public ParentNodeConstructor()
      Create a document or element node constructor instruction
  • Method Details

    • setBaseURI

      public void setBaseURI(String uri)
      Set the static base URI of the instruction
      Parameters:
      uri - the static base URI
    • getBaseURI

      public String getBaseURI()
      Get the static base URI of the instruction
      Returns:
      the static base URI
    • setLazyConstruction

      public void setLazyConstruction(boolean lazy)
      Indicate that lazy construction should (or should not) be used. Note that this request will be ignored if validation is required
      Parameters:
      lazy - set to true if lazy construction should be used
    • isLazyConstruction

      public final boolean isLazyConstruction()
      Establish whether lazy construction is to be used
      Returns:
      true if lazy construction is to be used
    • setSchemaType

      public void setSchemaType(SchemaType type)
      Set the schema type to be used for validation
      Parameters:
      type - the type to be used for validation. (For a document constructor, this is the required type of the document element)
    • getSchemaType

      public SchemaType getSchemaType()
      Get the schema type chosen for validation; null if not defined
      Returns:
      the type to be used for validation. (For a document constructor, this is the required type of the document element)
    • isNamespaceSensitive

      public boolean isNamespaceSensitive()
      Determine whether the schema type is namespace sensitive. The result is undefined if schemaType is null.
      Returns:
      true if the schema type is namespace sensitive
    • setValidationMode

      public void setValidationMode(int mode)
      Set the validation mode for the new document or element node
      Parameters:
      mode - the validation mode, for example Validation.STRICT
    • getValidationMode

      public int getValidationMode()
      Get the validation mode for this instruction
      Returns:
      the validation mode, for example Validation.STRICT or Validation.PRESERVE
    • setContentExpression

      public void setContentExpression(Expression content)
      Set the expression that constructs the content of the element
      Parameters:
      content - the content expression
    • getContentExpression

      public Expression getContentExpression()
      Get the expression that constructs the content of the element
      Returns:
      the content expression
    • computeCardinality

      public int computeCardinality()
      Get the cardinality of the sequence returned by evaluating this instruction
      Overrides:
      computeCardinality in class Instruction
      Returns:
      the static cardinality
    • simplify

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

      public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
      Description copied from class: Expression
      Perform type checking of an expression and its subexpressions. This is the second phase of static optimization.

      This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.

      This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.

      If the implementation returns a value other than "this", then it is required to ensure that the parent pointer and location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.

      Overrides:
      typeCheck in class Expression
      Parameters:
      visitor - an expression visitor
      contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
      Returns:
      the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
      Throws:
      XPathException - if an error is discovered during this phase (typically a type error)
    • checkContentSequence

      protected abstract void checkContentSequence(StaticContext env) throws XPathException
      Check that the child instructions don't violate any obvious constraints for this kind of node
      Parameters:
      env - the static context
      Throws:
      XPathException
    • optimize

      public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
      Description copied from class: Expression
      Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.

      This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

      Overrides:
      optimize in class Expression
      Parameters:
      visitor - an expression visitor
      contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
      Returns:
      the original expression, rewritten if appropriate to optimize execution
      Throws:
      XPathException - if an error is discovered during this phase (typically a type error)
    • promoteInst

      protected void promoteInst(PromotionOffer offer) throws XPathException
      Handle promotion offers, that is, non-local tree rewrites.
      Overrides:
      promoteInst in class Instruction
      Parameters:
      offer - The type of rewrite being offered
      Throws:
      XPathException
    • iterateSubExpressions

      public Iterator iterateSubExpressions()
      Get the immediate sub-expressions of this expression.
      Overrides:
      iterateSubExpressions in class Expression
      Returns:
      an iterator containing the sub-expressions of this expression
    • replaceSubExpression

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

      public final boolean createsNewNodes()
      Determine whether this instruction creates new nodes. This implementation returns true.
      Overrides:
      createsNewNodes in class Instruction
      Returns:
      true if the instruction creates new nodes (or if it can't be proved that it doesn't)
    • 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).
    • addToPathMap

      public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
      Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.

      The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.

      Overrides:
      addToPathMap in class Expression
      Parameters:
      pathMap - the PathMap to which the expression should be added
      pathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added
      Returns:
      the pathMapNodeSet representing the points in the source document that are both reachable by this expression, and that represent possible results of this expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.