org.apache.velocity.tools.generic
Class NumberTool

java.lang.Object
  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)