Package net.sf.saxon.expr

Class GeneralComparison10

java.lang.Object
net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.BinaryExpression
net.sf.saxon.expr.GeneralComparison10
All Implemented Interfaces:
Serializable, SourceLocator, Container, Expression, InstructionInfoProvider
public class GeneralComparison10 extends BinaryExpression
GeneralComparison10: a boolean expression that compares two expressions for equals, not-equals, greater-than or less-than. This implements the operators =, !=, <, >, etc. This version of the class implements general comparisons in XPath 1.0 backwards compatibility mode, as defined in the Oct 2004 revision of the specifications.
See Also:

  • Field Details

    • singletonOperator

      protected int singletonOperator

    • comparer

      protected AtomicComparer comparer

  • Constructor Details

    • GeneralComparison10

      public GeneralComparison10(Expression p0, int op, Expression p1)
      Create a general comparison 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

    • 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:
      net.sf.saxon.trans.StaticError - if an error is discovered during this phase (typically a type error)
      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:
      net.sf.saxon.trans.StaticError - if an error is discovered during this phase (typically a type error)
      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 a0, int operator, AtomicValue a1, 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
      Parameters:
      th -
      Returns:
      Type.BOOLEAN

    • displayOperator

      protected String displayOperator()
      Overrides:
      displayOperator in class BinaryExpression