net.sf.saxon.expr
Class ArithmeticExpression.NumericArithmetic

java.lang.Object
  |
  +--net.sf.saxon.expr.ComputedExpression
        |
        +--net.sf.saxon.expr.BinaryExpression
              |
              +--net.sf.saxon.expr.ArithmeticExpression
                    |
                    +--net.sf.saxon.expr.ArithmeticExpression.NumericArithmetic
All Implemented Interfaces:
Expression, java.io.Serializable
Enclosing class:
net.sf.saxon.expr.ArithmeticExpression

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

Inner class to handle numeric arithmetic expressions

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.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
protected  Expression[] operands
           
protected  int operator
           
 
Fields inherited from class net.sf.saxon.expr.ComputedExpression
lineNumber, NO_ARGUMENTS, staticProperties
 
Constructor Summary
ArithmeticExpression.NumericArithmetic(Expression p1, int operator, Expression p2)
           
 
Method Summary
 Expression analyze(StaticContext env)
          Type-check the expression statically.
 int computeCardinality()
          Determine the static cardinality
 void display(int level, NamePool pool)
          Diagnostic print of expression structure
protected  java.lang.String displayOperator()
           
 boolean equals(java.lang.Object other)
          Is this expression the same as another expression?
 Item evaluateItem(XPathContext context)
          Evaluate the expression.
 ItemType getItemType()
          Determine the data type of the expression, if this is known statically
 Expression[] getSubExpressions()
          Get the immediate subexpressions of this expression
 int hashCode()
          get HashCode for comparing two expressions.
protected static boolean isCommutative(int operator)
           
 Expression promote(PromotionOffer offer)
          Promote this expression if possible
 void setDetails(Expression p1, int op, Expression p2)
          Identify the two operands and the operator (for use when the default constructor was used)
 Expression simplify()
          Simplify an expression
 
Methods inherited from class net.sf.saxon.expr.ComputedExpression
computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSpecialProperties, iterate, markTailFunctionCalls, setLineNumber, typeError
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

operands

protected Expression[] operands

operator

protected int operator
Constructor Detail

ArithmeticExpression.NumericArithmetic

public ArithmeticExpression.NumericArithmetic(Expression p1,
                                              int operator,
                                              Expression p2)
Method Detail

evaluateItem

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

Specified by:
evaluateItem in interface Expression
Overrides:
evaluateItem in class net.sf.saxon.expr.ArithmeticExpression
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

analyze

public Expression analyze(StaticContext env)
                   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:
analyze in interface Expression
Overrides:
analyze in class net.sf.saxon.expr.BinaryExpression
Parameters:
env - the static context of the expression
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)

getItemType

public ItemType getItemType()
Determine the data type of the expression, if this is known statically

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

setDetails

public void setDetails(Expression p1,
                       int op,
                       Expression p2)
Identify the two operands and the operator (for use when the default constructor was used)

Parameters:
p1 - the left-hand operand
op - the operator, as a token returned by the Tokenizer (e.g. Tokenizer.AND)
p2 - the right-hand operand

simplify

public Expression simplify()
                    throws XPathException
Simplify an expression

Specified by:
simplify in interface Expression
Overrides:
simplify in class ComputedExpression
Returns:
the simplified expression
Throws:
XPathException - if an error is discovered during expression rewriting

promote

public Expression promote(PromotionOffer offer)
                   throws XPathException
Promote this expression if possible

Specified by:
promote in interface Expression
Overrides:
promote in class ComputedExpression
Parameters:
offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
Returns:
if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
Throws:
XPathException - if any error is detected

getSubExpressions

public Expression[] getSubExpressions()
Get the immediate subexpressions of this expression

Specified by:
getSubExpressions in interface Expression
Overrides:
getSubExpressions in class ComputedExpression
Returns:
an array containing the sub-expressions of this expression

computeCardinality

public int computeCardinality()
Determine the static cardinality

Specified by:
computeCardinality in class ComputedExpression

isCommutative

protected static boolean isCommutative(int operator)

equals

public boolean equals(java.lang.Object other)
Is this expression the same as another expression?

Overrides:
equals in class java.lang.Object

hashCode

public int hashCode()
get HashCode for comparing two expressions. Note that this hashcode gives the same result for (A op B) and for (B op A), whether or not the operator is commutative.

Overrides:
hashCode in class java.lang.Object

display

public void display(int level,
                    NamePool pool)
Diagnostic print of expression structure

Parameters:
level - indentation level for this expression

displayOperator

protected java.lang.String displayOperator()