net.sf.saxon.functions
Class FormatNumber

java.lang.Object
  |
  +--net.sf.saxon.expr.ComputedExpression
        |
        +--net.sf.saxon.expr.FunctionCall
              |
              +--net.sf.saxon.functions.SystemFunction
                    |
                    +--net.sf.saxon.functions.FormatNumber
All Implemented Interfaces:
Expression, java.io.Serializable, XSLTFunction

public class FormatNumber
extends SystemFunction
implements XSLTFunction

This is the original XSLT 1.0 implementation of format-number using the JDK directly. It is still available for the time being under the name format-number-1.0, in case the new version has problems.

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.ComputedExpression
lineNumber, NO_ARGUMENTS, staticProperties
 
Constructor Summary
FormatNumber()
           
 
Method Summary
 void checkArguments(StaticContext env)
          Method called during static type checking
 java.lang.String evaluateAsString(XPathContext context)
          Evaluate in a context where a string is wanted
 Item evaluateItem(XPathContext c)
          Evaluate in a general context
 java.lang.String formatNumber(double n, java.lang.String format, java.text.DecimalFormatSymbols dfs)
          Here is the method that does the work.
 Expression preEvaluate(StaticContext env)
          preEvaluate: this method suppresses compile-time evaluation by doing nothing.
 
Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, computeCardinality, display, getDetails, getItemType, getName, getRequiredType, main, makeSystemFunction, useContextItemAsDefault
 
Methods inherited from class net.sf.saxon.expr.FunctionCall
analyze, checkArgumentCount, getNumberOfArguments, getSubExpressions, promote, setArguments, simplify, simplifyArguments
 
Methods inherited from class net.sf.saxon.expr.ComputedExpression
computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSourceLocator, getSpecialProperties, iterate, markTailFunctionCalls, setLineNumber, typeError
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

FormatNumber

public FormatNumber()
Method Detail

checkArguments

public void checkArguments(StaticContext env)
                    throws XPathException
Description copied from class: SystemFunction
Method called during static type checking

Overrides:
checkArguments in class SystemFunction
XPathException

preEvaluate

public Expression preEvaluate(StaticContext env)
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

evaluateAsString

public java.lang.String evaluateAsString(XPathContext context)
                                  throws XPathException
Evaluate in a context where a string is wanted

Specified by:
evaluateAsString in interface Expression
Overrides:
evaluateAsString in class ComputedExpression
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 Expression
Overrides:
evaluateItem in class ComputedExpression
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

formatNumber

public java.lang.String formatNumber(double n,
                                     java.lang.String format,
                                     java.text.DecimalFormatSymbols dfs)
                              throws XPathException
Here is the method that does the work. It needs to be synchronized because it remembers information from one invocation to the next; it doesn't matter if these are in different threads but it can't be interrupted. The reason for remembering information is that getting a new DecimalFormatSymbols each time is incredibly expensive, especially with the Microsoft Java VM.

XPathException