Package net.sf.saxon.expr

Class AtomicSequenceConverter

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.UnaryExpression
net.sf.saxon.expr.AtomicSequenceConverter
All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, Locator
public final class AtomicSequenceConverter extends UnaryExpression
An AtomicSequenceConverter is an expression that performs a cast on each member of a supplied sequence
See Also:

  • Constructor Details

    • AtomicSequenceConverter

      public AtomicSequenceConverter(Expression sequence, AtomicType requiredItemType)
      Constructor
      Parameters:
      sequence - this must be a sequence of atomic values. This is not checked; a ClassCastException will occur if the precondition is not satisfied.
      requiredItemType - the item type to which all items in the sequence should be converted, using the rules for "cast as".

  • Method Details

    • getRequiredPrimitiveType

      public AtomicType getRequiredPrimitiveType()
      Get the required (target) primitive type
      Returns:
      the required primitive type

    • simplify

      public Expression simplify(ExpressionVisitor visitor) throws XPathException
      Simplify an expression
      Overrides:
      simplify in class UnaryExpression
      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
      Type-check the expression
      Overrides:
      typeCheck in class UnaryExpression
      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)

    • computeSpecialProperties

      public int computeSpecialProperties()
      Determine the special properties of this expression
      Overrides:
      computeSpecialProperties in class UnaryExpression
      Returns:
      StaticProperty.NON_CREATIVE.

    • 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

    • iterate

      public SequenceIterator iterate(XPathContext context) throws XPathException
      Iterate over the sequence of values
      Specified by:
      iterate in interface SequenceIterable
      Overrides:
      iterate in class Expression
      Parameters:
      context - supplies the context for evaluation
      Returns:
      a SequenceIterator that can be used to iterate over the result of the expression
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression

    • evaluateItem

      public Item evaluateItem(XPathContext context) throws XPathException
      Evaluate as an Item. This should only be called if the AtomicSequenceConverter has cardinality zero-or-one
      Specified by:
      evaluateItem in interface EvaluableItem
      Overrides:
      evaluateItem in class Expression
      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

    • getItemType

      public ItemType getItemType(TypeHierarchy th)
      Determine the data type of the items returned by the expression, if possible
      Overrides:
      getItemType in class UnaryExpression
      Parameters:
      th - the type hierarchy cache
      Returns:
      a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)

    • computeCardinality

      public int computeCardinality()
      Determine the static cardinality of the expression
      Overrides:
      computeCardinality in class UnaryExpression
      Returns:
      the computed cardinality, as one of the values StaticProperty.ALLOWS_ZERO_OR_ONE, StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE, StaticProperty.ALLOWS_ZERO_OR_MORE

    • equals

      public boolean equals(Object other)
      Is this expression the same as another expression?
      Overrides:
      equals in class UnaryExpression

    • explain

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