net.sf.saxon.functions
Class FormatNumber

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.FunctionCall
          net.sf.saxon.functions.SystemFunction
              net.sf.saxon.functions.FormatNumber

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, Locator

public class FormatNumber
extends SystemFunction

XSLT 2.0 implementation of format-number() function - removes the dependence on the JDK.

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.functions.SystemFunction

operation

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

argument

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

EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

FormatNumber()

Method Summary

static BigDecimal	adjustToDecimal(double value, int precision) Convert a double to a BigDecimal.
void	checkArguments(ExpressionVisitor visitor) Method called during static type checking
Expression	copy() Copy an expression.
CharSequence	evaluateAsString(XPathContext context) Evaluate in a context where a string is wanted
Item	evaluateItem(XPathContext c) Evaluate in a general context
Expression	preEvaluate(ExpressionVisitor visitor) preEvaluate: this method suppresses compile-time evaluation by doing nothing.

Methods inherited from class net.sf.saxon.functions.SystemFunction

addContextDocumentArgument, addDocToPathMap, computeCardinality, computeSpecialProperties, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

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

addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

FormatNumber

public FormatNumber()

Method Detail

checkArguments

public void checkArguments(ExpressionVisitor visitor)
                    throws XPathException

Description copied from class: SystemFunction

Method called during static type checking

Overrides:

checkArguments in class SystemFunction

Parameters:

visitor - the expression visitor

Throws:

XPathException

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)
                       throws XPathException

preEvaluate: this method suppresses compile-time evaluation by doing nothing. We can't evaluate early because we don't have access to the DecimalFormatManager.

Overrides:

preEvaluate in class FunctionCall

Parameters:

visitor - the expression visitor

Returns:

the result of the early evaluation, or the original expression, or potentially a simplified expression

Throws:

XPathException

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Overrides:

copy in class SystemFunction

Returns:

the copy of the original expression

evaluateAsString

public CharSequence evaluateAsString(XPathContext context)
                              throws XPathException

Evaluate in a context where a string is wanted

Overrides:

evaluateAsString in class Expression

Parameters:

context - The context in which the expression is to be evaluated

Returns:

the value of the expression, evaluated in the current context. The expression must return a string or (); if the value of the expression is (), this method returns "".

Throws:

XPathException - if any dynamic error occurs evaluating the expression

evaluateItem

public Item evaluateItem(XPathContext c)
                  throws XPathException

Evaluate in a general context

Specified by:

evaluateItem in interface EvaluableItem

Overrides:

evaluateItem in class Expression

Parameters:

c - 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

adjustToDecimal

public static BigDecimal adjustToDecimal(double value,
                                         int precision)

Convert a double to a BigDecimal. In general there will be several BigDecimal values that are equal to the supplied value, and the one we want to choose is the one with fewest non-zero digits. The algorithm used is rather pragmatic: look for a string of zeroes or nines, try rounding the number down or up as approriate, then convert the adjusted value to a double to see if it's equal to the original: if not, use the original value unchanged.

Parameters:

value - the double to be converted

precision - 2 for a double, 1 for a float

Returns:

the result of conversion to a double