Class UntypedSequenceConverter

All Implemented Interfaces:
ExportAgent, Locatable, IdentityComparable, Traceable

public final class UntypedSequenceConverter extends AtomicSequenceConverter
An UntypedSequenceConverter is an expression that performs a cast on each member of a supplied sequence that is an untypedAtomic value, while leaving other items unchanged
  • Constructor Details

    • UntypedSequenceConverter

      public UntypedSequenceConverter(Expression sequence, PlainType 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

    • makeUntypedSequenceConverter

      public static UntypedSequenceConverter makeUntypedSequenceConverter(Configuration config, Expression operand, PlainType requiredItemType) throws XPathException
      Create an AtomicSequenceConverter that converts all untypedAtomic values in the input sequence to a specified target type, while leaving items other than untypedAtomic unchanged
      Parameters:
      config - the Saxon configuration
      operand - the expression that delivers the input sequence
      requiredItemType - the type to which untypedAtomic values should be cast, which must either be an atomic type or a "plain" union type
      Returns:
      an AtomicSequenceConverter that performs the required conversion
      Throws:
      XPathException - if an error occurs, for example if the target type is namespace-sensitive
    • makeUntypedSequenceRejector

      public static UntypedSequenceConverter makeUntypedSequenceRejector(Configuration config, Expression operand, PlainType requiredItemType)
    • typeCheck

      public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
      Description copied from class: AtomicSequenceConverter
      Type-check the expression
      Overrides:
      typeCheck in class AtomicSequenceConverter
      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)
    • computeSpecialProperties

      protected int computeSpecialProperties()
      Determine the special properties of this expression
      Overrides:
      computeSpecialProperties in class AtomicSequenceConverter
      Returns:
      StaticProperty.NO_NODES_NEWLY_CREATED.
    • copy

      public Expression copy(RebindingMap rebindings)
      Copy an expression. This makes a deep copy.
      Overrides:
      copy in class AtomicSequenceConverter
      Parameters:
      rebindings - variables that need to be re-bound
      Returns:
      the copy of the original expression
    • getItemType

      public ItemType getItemType()
      Determine the data type of the items returned by the expression, if possible
      Overrides:
      getItemType in class AtomicSequenceConverter
      Returns:
      a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)
    • computeCardinality

      protected int computeCardinality()
      Determine the static cardinality of the expression
      Overrides:
      computeCardinality in class AtomicSequenceConverter
      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. May also return StaticProperty.ALLOWS_ZERO if the result is known to be an empty sequence, or StaticProperty.ALLOWS_MANY if if is known to return a sequence of length two or more.
    • equals

      public boolean equals(Object other)
      Is this expression the same as another expression?
      Overrides:
      equals in class AtomicSequenceConverter
      Parameters:
      other - the other operand; the result is false if this is not an Expression
      Returns:
      true if the other operand is an expression and if it can be determined that the two expressions are equivalent, in the sense that they will always return the same result.
    • computeHashCode

      protected int computeHashCode()
      get HashCode for comparing two expressions.
      Overrides:
      computeHashCode in class AtomicSequenceConverter
      Returns:
      a computed hash code
    • displayOperator

      protected String displayOperator(Configuration config)
      Description copied from class: UnaryExpression
      Give a string representation of the operator for use in diagnostics
      Overrides:
      displayOperator in class AtomicSequenceConverter
      Parameters:
      config - the Saxon configuration
      Returns:
      the operator, as a string
    • getExpressionName

      public String getExpressionName()
      Get a name identifying the kind of expression, in terms meaningful to a user.
      Overrides:
      getExpressionName in class AtomicSequenceConverter
      Returns:
      a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.
    • toShortString

      public String toShortString()
      Description copied from class: Expression
      Produce a short string identifying the expression for use in error messages
      Overrides:
      toShortString in class UnaryExpression
      Returns:
      a short string, sufficient to identify the expression
    • export

      public void export(ExpressionPresenter destination) throws XPathException
      Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
      Specified by:
      export in interface ExportAgent
      Overrides:
      export in class AtomicSequenceConverter
      Parameters:
      destination - the expression presenter used to display the structure
      Throws:
      XPathException - if the export fails, for example if an expression is found that won't work in the target environment.
    • getElaborator

      public Elaborator getElaborator()
      Make an elaborator for this expression
      Overrides:
      getElaborator in class AtomicSequenceConverter
      Returns:
      a suitable elaborator