org.apache.velocity.tools.generic
Class NumberTool

java.lang.Object
  extended by org.apache.velocity.tools.generic.NumberTool

public class NumberTool
extends java.lang.Object

Tool for working with Number in Velocity templates. It is useful for accessing and formatting arbitrary Number objects. Also the tool can be used to retrieve NumberFormat instances or make conversions to and from various number types.

 Example uses:
  $myNumber                            -> 13.55
  $number.format($myNumber)   -> 13.6
  $number.currency($myNumber) -> $13.55
  $number.integer($myNumber)  -> 13

 Example toolbox.xml config (if you want to use this with VelocityView):
 <tool>
   <key>number</key>
   <scope>application</scope>
   <class>org.apache.velocity.tools.generic.NumberTool</class>
   <parameter name="format" value="#0.0"/>
 </tool>
 

This tool is entirely threadsafe, and has no instance members. It may be used in any scope (request, session, or application). As such, the methods are highly interconnected, and overriding key methods provides an easy way to create subclasses that use a non-default format or locale.

Since:
VelocityTools 1.2
Version:
$Id: NumberTool.java 509841 2007-02-21 01:00:28Z nbubna $
Author:
Nathan Bubna, Mike Kienenberger

Field Summary
private  boolean configLocked
           
static java.lang.String DEFAULT_FORMAT
          The default format to be used when none is specified.
static java.lang.String DEFAULT_FORMAT_KEY
          The key used for specifying a default format via toolbox params.
static java.lang.String DEFAULT_LOCALE_KEY
          The key used for specifying a default locale via toolbox params.
private  java.lang.String format
           
private  java.util.Locale locale
           
static java.lang.String LOCK_CONFIG_KEY
          The key used for specifying whether or not to prevent templates from reconfiguring this tool.
private static int STYLE_CURRENCY
           
private static int STYLE_INTEGER
           
private static int STYLE_NUMBER
           
private static int STYLE_PERCENT
           
 
Constructor Summary
NumberTool()
           
 
Method Summary
 void configure(java.util.Map params)
          Looks for configuration values in the given params.
protected  void configure(ValueParser values)
          Does the actual configuration.
 java.lang.String currency(java.lang.Object obj)
          Convenience method equivalent to $number.format("currency", $foo).
 java.lang.String format(java.lang.Object obj)
          Converts the specified object to a number and formats it according to the pattern or style returned by getFormat().
 java.lang.String format(java.lang.String format, java.lang.Object obj)
          Converts the specified object to a number and returns a formatted string representing that number in the locale returned by getLocale().
 java.lang.String format(java.lang.String format, java.lang.Object obj, java.util.Locale locale)
          Converts the specified object to a number and returns a formatted string representing that number in the specified Locale.
 java.lang.String getFormat()
          Return the pattern or style to be used for formatting numbers when none is specified.
private  java.text.NumberFormat getIntegerInstance(java.util.Locale locale)
          Since we wish to continue supporting Java 1.3, for the present we cannot use Java 1.4's NumberFormat.getIntegerInstance(Locale) method.
 java.util.Locale getLocale()
          This implementation returns the configured default locale.
protected  java.text.NumberFormat getNumberFormat(int numberStyle, java.util.Locale locale)
          Returns a NumberFormat instance for the specified number style and Locale.
 java.text.NumberFormat getNumberFormat(java.lang.String format, java.util.Locale locale)
          Returns a NumberFormat instance for the specified format and Locale.
protected  int getStyleAsInt(java.lang.String style)
          Checks a string to see if it matches one of the standard NumberFormat style patterns: NUMBER, CURRENCY, PERCENT, INTEGER, or DEFAULT.
 java.lang.String integer(java.lang.Object obj)
          Convenience method equivalent to $number.format("integer", $foo).
 java.lang.String number(java.lang.Object obj)
          Convenience method equivalent to $number.format("number", $foo).
 java.lang.String percent(java.lang.Object obj)
          Convenience method equivalent to $number.format("percent", $foo).
protected  void setFormat(java.lang.String format)
          Sets the default format for this instance.
protected  void setLocale(java.util.Locale locale)
          Sets the default locale for this instance.
 java.lang.Number toNumber(java.lang.Object obj)
          Converts an object to an instance of Number using the format returned by getFormat() and the Locale returned by getLocale() if the object is not already an instance of Number.
 java.lang.Number toNumber(java.lang.String format, java.lang.Object obj)
          Converts an object to an instance of Number using the specified format and the Locale returned by getLocale() if the object is not already an instance of Number.
 java.lang.Number toNumber(java.lang.String format, java.lang.Object obj, java.util.Locale locale)
          Converts an object to an instance of Number using the specified format and Localeif the object is not already an instance of Number.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

DEFAULT_FORMAT

public static final java.lang.String DEFAULT_FORMAT
The default format to be used when none is specified.

See Also:
Constant Field Values

DEFAULT_FORMAT_KEY

public static final java.lang.String DEFAULT_FORMAT_KEY
The key used for specifying a default format via toolbox params.

Since:
VelocityTools 1.4
See Also:
Constant Field Values

DEFAULT_LOCALE_KEY

public static final java.lang.String DEFAULT_LOCALE_KEY
The key used for specifying a default locale via toolbox params.

Since:
VelocityTools 1.4
See Also:
Constant Field Values

LOCK_CONFIG_KEY

public static final java.lang.String LOCK_CONFIG_KEY
The key used for specifying whether or not to prevent templates from reconfiguring this tool. The default is true.

Since:
VelocityTools 1.4
See Also:
Constant Field Values

STYLE_NUMBER

private static final int STYLE_NUMBER
See Also:
Constant Field Values

STYLE_CURRENCY

private static final int STYLE_CURRENCY
See Also:
Constant Field Values

STYLE_PERCENT

private static final int STYLE_PERCENT
See Also:
Constant Field Values

STYLE_INTEGER

private static final int STYLE_INTEGER
See Also:
Constant Field Values

format

private java.lang.String format

locale

private java.util.Locale locale

configLocked

private boolean configLocked
Constructor Detail

NumberTool

public NumberTool()
Method Detail

configure

public void configure(java.util.Map params)
Looks for configuration values in the given params.

Since:
VelocityTools 1.4

configure

protected void configure(ValueParser values)
Does the actual configuration. This is protected, so subclasses may share the same ValueParser and call configure at any time, while preventing templates from doing so when configure(Map) is locked.

Since:
VelocityTools 1.4

getLocale

public java.util.Locale getLocale()
This implementation returns the configured default locale. Subclasses may override this to return alternate locales. Please note that doing so will affect all formatting methods where no locale is specified in the parameters.

Returns:
the default Locale

setLocale

protected void setLocale(java.util.Locale locale)
Sets the default locale for this instance. This is protected, because templates ought not to be using it; that would not be threadsafe so far as templates are concerned.

Since:
VelocityTools 1.4

getFormat

public java.lang.String getFormat()
Return the pattern or style to be used for formatting numbers when none is specified. This implementation gives a 'default' number format. Subclasses may override this to provide a different default format.


setFormat

protected void setFormat(java.lang.String format)
Sets the default format for this instance. This is protected, because templates ought not to be using it; that would not be threadsafe so far as templates are concerned.

Since:
VelocityTools 1.4

format

public java.lang.String format(java.lang.Object obj)
Converts the specified object to a number and formats it according to the pattern or style returned by getFormat().

Parameters:
obj - the number object to be formatted
Returns:
the specified number formatted as a string
See Also:
format(String format, Object obj, Locale locale)

currency

public java.lang.String currency(java.lang.Object obj)
Convenience method equivalent to $number.format("currency", $foo).

Since:
VelocityTools 1.3

integer

public java.lang.String integer(java.lang.Object obj)
Convenience method equivalent to $number.format("integer", $foo).

Since:
VelocityTools 1.3

number

public java.lang.String number(java.lang.Object obj)
Convenience method equivalent to $number.format("number", $foo).

Since:
VelocityTools 1.3

percent

public java.lang.String percent(java.lang.Object obj)
Convenience method equivalent to $number.format("percent", $foo).

Since:
VelocityTools 1.3

format

public java.lang.String format(java.lang.String format,
                               java.lang.Object obj)
Converts the specified object to a number and returns a formatted string representing that number in the locale returned by getLocale().

Parameters:
format - the formatting instructions
obj - the number object to be formatted
Returns:
a formatted string for this locale representing the specified number or null if the parameters are invalid
See Also:
format(String format, Object obj, Locale locale)

format

public java.lang.String format(java.lang.String format,
                               java.lang.Object obj,
                               java.util.Locale locale)
Converts the specified object to a number and returns a formatted string representing that number in the specified Locale.

Parameters:
format - the custom or standard pattern to be used
obj - the number object to be formatted
locale - the Locale to be used when formatting
Returns:
a formatted string representing the specified number or null if the parameters are invalid

getNumberFormat

public java.text.NumberFormat getNumberFormat(java.lang.String format,
                                              java.util.Locale locale)
Returns a NumberFormat instance for the specified format and Locale. If the format specified is a standard style pattern, then a number instance will be returned with the number style set to the specified style. If it is a custom format, then a customized NumberFormat will be returned.

Parameters:
format - the custom or standard formatting pattern to be used
locale - the Locale to be used
Returns:
an instance of NumberFormat
See Also:
NumberFormat

getNumberFormat

protected java.text.NumberFormat getNumberFormat(int numberStyle,
                                                 java.util.Locale locale)
Returns a NumberFormat instance for the specified number style and Locale.

Parameters:
numberStyle - the number style (number will be ignored if this is less than zero or the number style is not recognized)
locale - the Locale to be used
Returns:
an instance of NumberFormat or null if an instance cannot be constructed with the given parameters

getIntegerInstance

private java.text.NumberFormat getIntegerInstance(java.util.Locale locale)
Since we wish to continue supporting Java 1.3, for the present we cannot use Java 1.4's NumberFormat.getIntegerInstance(Locale) method. This method mimics that method (at least as of JDK1.4.2_01). It is private so that it can be removed later without a deprecation period.


getStyleAsInt

protected int getStyleAsInt(java.lang.String style)
Checks a string to see if it matches one of the standard NumberFormat style patterns: NUMBER, CURRENCY, PERCENT, INTEGER, or DEFAULT. if it does it will return the integer constant for that pattern. if not, it will return -1.

Parameters:
style - the string to be checked
Returns:
the int identifying the style pattern
See Also:
NumberFormat

toNumber

public java.lang.Number toNumber(java.lang.Object obj)
Converts an object to an instance of Number using the format returned by getFormat() and the Locale returned by getLocale() if the object is not already an instance of Number.

Parameters:
obj - the number to convert
Returns:
the object as a Number or null if no conversion is possible

toNumber

public java.lang.Number toNumber(java.lang.String format,
                                 java.lang.Object obj)
Converts an object to an instance of Number using the specified format and the Locale returned by getLocale() if the object is not already an instance of Number.

Parameters:
format - - the format the number is in
obj - - the number to convert
Returns:
the object as a Number or null if no conversion is possible
See Also:
toNumber(String format, Object obj, Locale locale)

toNumber

public java.lang.Number toNumber(java.lang.String format,
                                 java.lang.Object obj,
                                 java.util.Locale locale)
Converts an object to an instance of Number using the specified format and Localeif the object is not already an instance of Number.

Parameters:
format - - the format the number is in
obj - - the number to convert
locale - - the Locale
Returns:
the object as a Number or null if no conversion is possible
See Also:
NumberFormat.parse(java.lang.String, java.text.ParsePosition)


Copyright (c) 2003-2007 Apache Software Foundation