net.sf.saxon.expr
Class Calculator

java.lang.Object
  extended by net.sf.saxon.expr.Calculator
All Implemented Interfaces:
Serializable

public abstract class Calculator
extends Object
implements Serializable

This class evaluates arithmetic expressions; it acts as a helper class to the ArithmeticExpression class. There are many subclasses for the different kinds of arithmetic expression, and static methods that allow the right subclass to be selected, either at compile time or at run time.

See Also:
Serialized Form

Field Summary
static Calculator[] ANY_ANY
          Calculators used for the six operators when the static type information does not allow a more specific calculator to be chosen
static Calculator[] DATETIME_DATETIME
          Calculators used when both operands are xs:dateTime, xs:date, or xs:time
static Calculator[] DATETIME_DURATION
          Calculators used when the first operand is xs:dateTime, xs:date, or xs:time, and the second is a duration
static Calculator[] DECIMAL_DECIMAL
           
static Calculator[] DECIMAL_DOUBLE
          Calculators used when the first operand is a decimal
static Calculator[] DECIMAL_FLOAT
           
static Calculator[] DECIMAL_INTEGER
           
static int DIV
           
static Calculator[] DOUBLE_DECIMAL
           
static Calculator[] DOUBLE_DOUBLE
          Calculators used when the first operand is a double
static Calculator[] DOUBLE_FLOAT
           
static Calculator[] DOUBLE_INTEGER
           
static Calculator[] DURATION_DATETIME
          Calculators used when the second operand is xs:dateTime, xs:date, or xs:time, and the first is a duration
static Calculator[] DURATION_DURATION
          Calculators used when the both operands are durations
static Calculator[] DURATION_NUMERIC
          Calculators used when the first operand is a duration and the second is numeric
static Calculator[] FLOAT_DECIMAL
           
static Calculator[] FLOAT_DOUBLE
          Calculators used when the first operand is a float
static Calculator[] FLOAT_FLOAT
           
static Calculator[] FLOAT_INTEGER
           
static int IDIV
           
static Calculator[] INTEGER_DECIMAL
           
static Calculator[] INTEGER_DOUBLE
          Calculators used when the first operand is an integer
static Calculator[] INTEGER_FLOAT
           
static Calculator[] INTEGER_INTEGER
           
static int MINUS
           
static int MOD
           
static Calculator[] NUMERIC_DURATION
          Calculators used when the second operand is a duration and the first is numeric
static int PLUS
           
static int TIMES
           
 
Constructor Summary
Calculator()
           
 
Method Summary
abstract  AtomicValue compute(AtomicValue a, AtomicValue b, XPathContext c)
          Perform an arithmetic operation
static Calculator getCalculator(int typeA, int typeB, int operator, boolean mustResolve)
          Factory method to get a calculator for a given combination of types
static String getCalculatorSetName(int typeA, int typeB)
          Get the name of the calculator set for a given combination of types
abstract  AtomicType getResultType(AtomicType typeA, AtomicType typeB)
          Get the type of the result of the calculator, given arguments types typeA and typeB
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

PLUS

public static final int PLUS
See Also:
Constant Field Values

MINUS

public static final int MINUS
See Also:
Constant Field Values

TIMES

public static final int TIMES
See Also:
Constant Field Values

DIV

public static final int DIV
See Also:
Constant Field Values

MOD

public static final int MOD
See Also:
Constant Field Values

IDIV

public static final int IDIV
See Also:
Constant Field Values

ANY_ANY

public static Calculator[] ANY_ANY
Calculators used for the six operators when the static type information does not allow a more specific calculator to be chosen


DOUBLE_DOUBLE

public static Calculator[] DOUBLE_DOUBLE
Calculators used when the first operand is a double


DOUBLE_FLOAT

public static Calculator[] DOUBLE_FLOAT

DOUBLE_DECIMAL

public static Calculator[] DOUBLE_DECIMAL

DOUBLE_INTEGER

public static Calculator[] DOUBLE_INTEGER

FLOAT_DOUBLE

public static Calculator[] FLOAT_DOUBLE
Calculators used when the first operand is a float


FLOAT_FLOAT

public static Calculator[] FLOAT_FLOAT

FLOAT_DECIMAL

public static Calculator[] FLOAT_DECIMAL

FLOAT_INTEGER

public static Calculator[] FLOAT_INTEGER

DECIMAL_DOUBLE

public static Calculator[] DECIMAL_DOUBLE
Calculators used when the first operand is a decimal


DECIMAL_FLOAT

public static Calculator[] DECIMAL_FLOAT

DECIMAL_DECIMAL

public static Calculator[] DECIMAL_DECIMAL

DECIMAL_INTEGER

public static Calculator[] DECIMAL_INTEGER

INTEGER_DOUBLE

public static Calculator[] INTEGER_DOUBLE
Calculators used when the first operand is an integer


INTEGER_FLOAT

public static Calculator[] INTEGER_FLOAT

INTEGER_DECIMAL

public static Calculator[] INTEGER_DECIMAL

INTEGER_INTEGER

public static Calculator[] INTEGER_INTEGER

DATETIME_DATETIME

public static Calculator[] DATETIME_DATETIME
Calculators used when both operands are xs:dateTime, xs:date, or xs:time


DATETIME_DURATION

public static Calculator[] DATETIME_DURATION
Calculators used when the first operand is xs:dateTime, xs:date, or xs:time, and the second is a duration


DURATION_DATETIME

public static Calculator[] DURATION_DATETIME
Calculators used when the second operand is xs:dateTime, xs:date, or xs:time, and the first is a duration


DURATION_DURATION

public static Calculator[] DURATION_DURATION
Calculators used when the both operands are durations


DURATION_NUMERIC

public static Calculator[] DURATION_NUMERIC
Calculators used when the first operand is a duration and the second is numeric


NUMERIC_DURATION

public static Calculator[] NUMERIC_DURATION
Calculators used when the second operand is a duration and the first is numeric

Constructor Detail

Calculator

public Calculator()
Method Detail

getCalculator

public static Calculator getCalculator(int typeA,
                                       int typeB,
                                       int operator,
                                       boolean mustResolve)
Factory method to get a calculator for a given combination of types

Parameters:
typeA - fingerprint of the primitive type of the first operand
typeB - fingerprint of the primitive type of the second operand
operator - the arithmetic operator in use
mustResolve - indicates that a concrete Calculator is required (rather than an ANY_ANY calculator which needs to be further resolved at run-time)
Returns:
null if no suitable Calculator can be found.

getCalculatorSetName

public static String getCalculatorSetName(int typeA,
                                          int typeB)
Get the name of the calculator set for a given combination of types

Parameters:
typeA - the fingerprint of the primitive type of the first operand
typeB - the fingerprint of the primitive type of the second operand
Returns:
null if no suitable Calculator can be found.

compute

public abstract AtomicValue compute(AtomicValue a,
                                    AtomicValue b,
                                    XPathContext c)
                             throws XPathException
Perform an arithmetic operation

Parameters:
a - the first operand. Must not be null, and must be an instance of the type implied by the class name.
b - the second operand. Must not be null, and must be an instance of the type implied by the class name.
c - the XPath dynamic evaluation context
Returns:
the result of the computation, as a value of the correct primitive type
Throws:
XPathException - in the event of an arithmetic error

getResultType

public abstract AtomicType getResultType(AtomicType typeA,
                                         AtomicType typeB)
Get the type of the result of the calculator, given arguments types typeA and typeB

Parameters:
typeA - the type of the first operand
typeB - the type of the second operand
Returns:
the type of the result


Copyright (C) Michael H. Kay. All rights reserved.