Class GeneralComparison

java.lang.Object
net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.BinaryExpression
net.sf.saxon.expr.GeneralComparison
All Implemented Interfaces:
Serializable, SourceLocator, ComparisonExpression, Container, Expression, InstructionInfoProvider
public class GeneralComparison extends BinaryExpression implements ComparisonExpression
GeneralComparison: a boolean expression that compares two expressions for equals, not-equals, greater-than or less-than. This implements the operators =, !=, invalid input: '<', >, etc. This implementation is not used when in backwards-compatible mode
See Also:

  • Field Details

    • singletonOperator

      protected int singletonOperator

    • comparer

      protected transient AtomicComparer comparer

  • Constructor Details

    • GeneralComparison

      public GeneralComparison(Expression p0, int op, Expression p1)
      Create a relational expression identifying the two operands and the operator
      Parameters:
      p0 - the left-hand operand
      op - the operator, as a token returned by the Tokenizer (e.g. Token.LT)
      p1 - the right-hand operand

  • Method Details

    • getAtomicComparer

      public AtomicComparer getAtomicComparer()
      Get the AtomicComparer used to compare atomic values. This encapsulates any collation that is used
      Specified by:
      getAtomicComparer in interface ComparisonExpression

    • getSingletonOperator

      public int getSingletonOperator()
      Get the primitive (singleton) operator used: one of Token.FEQ, Token.FNE, Token.FLT, Token.FGT, Token.FLE, Token.FGE
      Specified by:
      getSingletonOperator in interface ComparisonExpression

    • convertsUntypedToOther

      public boolean convertsUntypedToOther()
      Determine whether untyped atomic values should be converted to the type of the other operand
      Specified by:
      convertsUntypedToOther in interface ComparisonExpression
      Returns:
      true if untyped values should be converted to the type of the other operand, false if they should be converted to strings.

    • computeCardinality

      public int computeCardinality()
      Determine the static cardinality. Returns [1..1]
      Overrides:
      computeCardinality in class BinaryExpression

    • typeCheck

      public Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException
      Type-check the expression
      Specified by:
      typeCheck in interface Expression
      Overrides:
      typeCheck in class BinaryExpression
      Parameters:
      env - the static context of the expression
      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 checked expression
      Throws:
      XPathException

    • optimize

      public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException
      Optimize the expression
      Specified by:
      optimize in interface Expression
      Overrides:
      optimize in class BinaryExpression
      Parameters:
      opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.
      env - the static context of the expression
      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 checked expression
      Throws:
      XPathException

    • evaluateItem

      public Item evaluateItem(XPathContext context) throws XPathException
      Evaluate the expression in a given context
      Specified by:
      evaluateItem in interface Expression
      Overrides:
      evaluateItem in class ComputedExpression
      Parameters:
      context - the given context for evaluation
      Returns:
      a BooleanValue representing the result of the numeric comparison of the two operands
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression

    • effectiveBooleanValue

      public boolean effectiveBooleanValue(XPathContext context) throws XPathException
      Evaluate the expression in a boolean context
      Specified by:
      effectiveBooleanValue in interface Expression
      Overrides:
      effectiveBooleanValue in class ComputedExpression
      Parameters:
      context - the given context for evaluation
      Returns:
      a boolean representing the result of the numeric comparison of the two operands
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression

    • compare

      protected static boolean compare(AtomicValue a1, int operator, AtomicValue a2, AtomicComparer comparer, XPathContext context) throws XPathException
      Compare two atomic values
      Throws:
      XPathException

    • getItemType

      public ItemType getItemType(TypeHierarchy th)
      Determine the data type of the expression
      Specified by:
      getItemType in interface Expression
      Parameters:
      th -
      Returns:
      Type.BOOLEAN

    • getInverseComparison

      protected GeneralComparison getInverseComparison()

    • displayOperator

      protected String displayOperator()
      Overrides:
      displayOperator in class BinaryExpression