## net.sf.saxon.expr
Class ArithmeticExpression.DateDifference

    java.lang.Object
      net.sf.saxon.expr.ComputedExpression
          net.sf.saxon.expr.BinaryExpression
              net.sf.saxon.expr.ArithmeticExpression
                  net.sf.saxon.expr.ArithmeticExpression.DateDifference

All Implemented Interfaces:
  Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator

Enclosing class:
  net.sf.saxon.expr.ArithmeticExpression

public static class ArithmeticExpression.DateDifference
extends net.sf.saxon.expr.ArithmeticExpression

Inner class to handle subtraction of a Date (or Time, or DateTime) from another, to return a Duration

See Also:
  Serialized Form

Nested Class Summary
`static class` `ArithmeticExpression.DateAndDuration` Inner class to handle addition or subtraction of a Date (or Time, or DateTime) and a Duration
`static class` `ArithmeticExpression.DateDifference` Inner class to handle subtraction of a Date (or Time, or DateTime) from another, to return a Duration
`static class` `ArithmeticExpression.DurationAddition` Inner class to handle addition and subtraction of two durations
`static class` `ArithmeticExpression.DurationDivision` Inner class to handle division of two durations to give a number
`static class` `ArithmeticExpression.DurationMultiplication` Inner class to handle multiplication (or division) of a duration by a number
`static class` `ArithmeticExpression.NumericArithmetic` Inner class to handle numeric arithmetic expressions

Field Summary

Fields inherited from class net.sf.saxon.expr.BinaryExpression
`operand0, operand1, operator`

Fields inherited from class net.sf.saxon.expr.ComputedExpression
`locationId, staticProperties`

Fields inherited from interface net.sf.saxon.expr.Expression
`EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD`

Constructor Summary
`ArithmeticExpression.DateDifference(Expression p1, int operator, Expression p2)`

Method Summary
`static Item` `doArithmetic(Expression operand0, Expression operand1, XPathContext context)`
`Item` `evaluateItem(XPathContext context)` Evaluate the expression.
`ItemType` `getItemType(TypeHierarchy th)` Determine the data type of the expression, if this is known statically
`Expression` `typeCheck(StaticContext env, ItemType contextItemType)` Type-check the expression statically.

Methods inherited from class net.sf.saxon.expr.BinaryExpression
`computeCardinality, computeSpecialProperties, display, displayOperator, equals, getOperands, getOperator, hashCode, isCommutative, isInverse, iterateSubExpressions, optimize, promote, simplify`

Methods inherited from class net.sf.saxon.expr.ComputedExpression

`adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, suppressValidation, typeError, typeError`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### ArithmeticExpression.DateDifference

    public ArithmeticExpression.DateDifference(Expression p1,
                                               int operator,
                                               Expression p2)

Method Detail

### evaluateItem

    public Item evaluateItem(XPathContext context)
                      throws XPathException

  Evaluate the expression.

  Throws:
    `XPathException`

### doArithmetic

    public static Item doArithmetic(Expression operand0,
                                    Expression operand1,
                                    XPathContext context)
                             throws XPathException

  Throws:
    `XPathException`

### typeCheck

    public Expression typeCheck(StaticContext env,
                                ItemType 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.

  Specified by:
    `typeCheck` in interface `Expression`
  Overrides:
    `typeCheck` in class `BinaryExpression`
  Throws:
    `XPathException`

### getItemType

    public ItemType getItemType(TypeHierarchy th)

  Determine the data type of the expression, if this is known statically

  Parameters:
    `th` -
  Returns:
    a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)