net.sf.saxon.expr
Class ArithmeticExpression

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.BinaryExpression
          net.sf.saxon.expr.ArithmeticExpression

All Implemented Interfaces:

Serializable, SourceLocator, Container, EvaluableItem, SequenceIterable, InstructionInfoProvider

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:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

ArithmeticExpression(Expression p1, int operator, Expression p2)

Method Summary

Item	evaluateItem(XPathContext context) Evaluate the expression.
Calculator	getCalculator() Get the calculator allocated to evaluate this expression
ItemType	getItemType(TypeHierarchy th) Determine the data type of the expression, if this is known statically
boolean	isBackwardsCompatible() Determine whether the expression is to be evaluated in backwards-compatible mode
static int	mapOpCode(int op) Map operator codes from those in the Token class to those in the Calculator class
Expression	simplify(StaticContext env) Simplify an expression
Expression	typeCheck(StaticContext env, ItemType contextItemType) Type-check the expression statically.

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

computeCardinality, computeSpecialProperties, display, equals, getOperands, getOperator, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression

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

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

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ArithmeticExpression

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

Method Detail

simplify

public Expression simplify(StaticContext env)
                    throws XPathException

Description copied from class: BinaryExpression

Simplify an expression

Overrides:

simplify in class BinaryExpression

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

isBackwardsCompatible

public boolean isBackwardsCompatible()

Determine whether the expression is to be evaluated in backwards-compatible mode

getCalculator

public Calculator getCalculator()

Get the calculator allocated to evaluate this expression

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.

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 original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

StaticError - if an error is discovered during this phase (typically a type error)

XPathException

mapOpCode

public static int mapOpCode(int op)

Map operator codes from those in the Token class to those in the Calculator class

getItemType

public ItemType getItemType(TypeHierarchy th)

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

Specified by:

getItemType in class Expression

Parameters:

th -

Returns:

a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluate the expression.

Specified by:

evaluateItem in interface EvaluableItem

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