Package net.sf.saxon.expr.instruct

Class ParentNodeConstructor

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.instruct.Instruction
net.sf.saxon.expr.instruct.ParentNodeConstructor
All Implemented Interfaces:
ExportAgent, InstructionWithComplexContent, ValidatingInstruction, Locatable, IdentityComparable, Traceable
Direct Known Subclasses:
DocumentInstr, ElementCreator
public abstract class ParentNodeConstructor extends Instruction implements ValidatingInstruction, InstructionWithComplexContent
An abstract class to act as a common parent for instructions that create element nodes and document nodes.

  • Field Details

    • contentOp

      protected Operand contentOp

    • preservingTypes

      protected boolean preservingTypes
      Flag set to true if validation=preserve and no schema type supplied for validation; also true when validation="strip" if there is no need to physically strip type annotations

  • Constructor Details

    • ParentNodeConstructor

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

  • Method Details

    • getSchemaType

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

    • getValidationOptions

      public ParseOptions getValidationOptions()
      Get the validation options
      Returns:
      the validation options for the content of the constructed node. May be null if no validation was requested.

    • setValidationOptions

      public void setValidationOptions(ParseOptions options)

    • setValidationAction

      public void setValidationAction(int mode, SchemaType schemaType)
      Set the validation mode for the new document or element node
      Parameters:
      mode - the validation mode, for example Validation.STRICT
      schemaType - the required type (for validation by type). Null if not validating by type

    • getValidationAction

      public int getValidationAction()
      Get the validation mode for this instruction
      Specified by:
      getValidationAction in interface ValidatingInstruction
      Returns:
      the validation mode, for example Validation.STRICT or Validation.PRESERVE

    • setNoNeedToStrip

      public void setNoNeedToStrip()
      Set that the newly constructed node and everything underneath it will automatically be untyped, without any need to physically remove type annotations, even though validation=STRIP is set.

    • 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
      Specified by:
      getContentExpression in interface InstructionWithComplexContent
      Returns:
      the content expression

    • getContentOperand

      public Operand getContentOperand()

    • computeCardinality

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

    • typeCheck

      public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) 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.

      Overrides:
      typeCheck in class Expression
      Parameters:
      visitor - an expression visitor
      contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.
      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)

    • allowExtractingCommonSubexpressions

      public boolean allowExtractingCommonSubexpressions()
      Ask whether common subexpressions found in the operands of this expression can be extracted and evaluated outside the expression itself. The result is irrelevant in the case of operands evaluated with a different focus, which will never be extracted in this way, even if they have no focus dependency.
      Overrides:
      allowExtractingCommonSubexpressions in class Expression
      Returns:
      false for this kind of expression

    • 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 - if the check fails

    • optimize

      public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo 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)

    • mayCreateNewNodes

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

    • alwaysCreatesNewNodes

      public boolean alwaysCreatesNewNodes()
      Ask whether it is guaranteed that every item in the result of this instruction is a newly created node
      Overrides:
      alwaysCreatesNewNodes in class Instruction
      Returns:
      true if result of the instruction is always either an empty sequence or a sequence consisting entirely of newly created nodes

    • 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.

    • isPreservingTypes

      public boolean isPreservingTypes()
      Determine whether this elementCreator performs validation or strips type annotations
      Returns:
      false if the instruction performs validation of the constructed output or if it strips type annotations, otherwise true

    • isLocal

      public boolean isLocal()