Class ArithmeticExpression

All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, InstructionInfo, Locator

public class ArithmeticExpression extends BinaryExpression
Arithmetic Expression: an expression using one of the operators plus, minus, multiply, div, idiv, mod. Note that this code does not handle backwards compatibility mode: see ArithmeticExpression10
See Also:
  • Field Details

    • simplified

      protected boolean simplified
  • Constructor Details

    • ArithmeticExpression

      public ArithmeticExpression(Expression p0, int operator, Expression p1)
      Create an arithmetic expression
      Parameters:
      p0 - the first operand
      operator - the operator, for example Token.PLUS
      p1 - the second operand
  • Method Details

    • getExpressionName

      public String getExpressionName()
      Get a name identifying the kind of expression, in terms meaningful to a user.
      Overrides:
      getExpressionName in class Expression
      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.
    • simplify

      public Expression simplify(ExpressionVisitor visitor) throws XPathException
      Description copied from class: BinaryExpression
      Simplify an expression
      Overrides:
      simplify in class BinaryExpression
      Parameters:
      visitor - an expression visitor
      Returns:
      the simplified expression
      Throws:
      XPathException - if an error is discovered during expression rewriting
    • getCalculator

      public Calculator getCalculator()
      Get the calculator allocated to evaluate this expression
      Returns:
      the calculator, a helper object that does the actual calculation
    • typeCheck

      public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
      Type-check the expression statically. We try to work out which particular arithmetic function to use if the types of operands are known an compile time.
      Overrides:
      typeCheck in class BinaryExpression
      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)
    • getIntegerBounds

      public IntegerValue[] getIntegerBounds()
      For an expression that returns an integer or a sequence of integers, get a lower and upper bound on the values of the integers that may be returned, from static analysis. The default implementation returns null, meaning "unknown" or "not applicable". Other implementations return an array of two IntegerValue objects, representing the lower and upper bounds respectively. The values UNBOUNDED_LOWER and UNBOUNDED_UPPER are used by convention to indicate that the value may be arbitrarily large. The values MAX_STRING_LENGTH and MAX_SEQUENCE_LENGTH are used to indicate values limited by the size of a string or the size of a sequence.
      Overrides:
      getIntegerBounds in class Expression
      Returns:
      the lower and upper bounds of integer values in the result, or null to indicate unknown or not applicable.
    • 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
    • compute

      public static AtomicValue compute(AtomicValue value0, int operator, AtomicValue value1, XPathContext context) throws XPathException
      Static method to apply arithmetic to two values
      Parameters:
      value0 - the first value
      operator - the operator as denoted in the Calculator class, for example Calculator.PLUS
      value1 - the second value
      context - the XPath dynamic evaluation context
      Returns:
      the result of the arithmetic operation
      Throws:
      XPathException
    • mapOpCode

      public static int mapOpCode(int op)
      Map operator codes from those in the Token class to those in the Calculator class
      Parameters:
      op - an operator denoted by a constant in the Token class, for example Token.PLUS
      Returns:
      an operator denoted by a constant defined in the Calculator class, for example Calculator.PLUS
    • getItemType

      public ItemType getItemType(TypeHierarchy th)
      Determine the data type of the expression, insofar as this is known statically
      Specified by:
      getItemType in class Expression
      Parameters:
      th - the type hierarchy cache
      Returns:
      the atomic type of the result of this arithmetic expression
    • evaluateItem

      public Item evaluateItem(XPathContext context) throws XPathException
      Evaluate the expression.
      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