ToStringTransformer (JGUIraffe BOM 1.3.1 API)

java.lang.Object
- net.sf.jguiraffe.transform.ToStringTransformer

All Implemented Interfaces:

Transformer
```
public class ToStringTransformer
extends Object
implements Transformer
```
A generic Transformer implementation that transforms arbitrary objects into formatted strings.

This implementation can be used for transforming data of the most common data types to be presented in form input fields (especially text fields). Based on the type of the passed in object a specific transforming method will be invoked. The following data types are supported:
- java.util.Date objects will be formatted using a DateFormat object for the current locale. With the setDateFormatStyle() the specific formatting style can be defined (one of the constants defined by the DateFormat class like SHORT, MEDIUM, or FULL. The class will always use a date instance for doing the formatting. So if other formats are needed (e.g. only the time portion or both date and time), a different Transformer implementation must be used.
- Decimal numbers will be formatted using a NumberFormat object initialized for the current locale. For configuring the format a set of properties is available matching the options of NumberFormat (e.g. the grouping flag or the maximum number of fraction digits).
- Integer numbers are treated in a similar way as decimal numbers. They are also transformed using a NumberFormat object, but no fraction digits will be output.
- For all other objects their toString() method will be invoked.
- A null input results in an empty string.
The properties that configure the formatting can be set through the bean-style set methods. When declaring an input element in a builder script and assigning a Transformer to it, it is also possible to specify properties, which will then override the settings stored in the object's properties. These properties have the same names as the bean properties defined by this class, e.g. the groupingUsed property corresponds to the setGroupingUsed() method.

An instance of this Transformer implementation can be shared between multiple input components. It is possible to create a single instance (e.g. using the dependency injection framework) and initialize it with default settings. If single input components require different settings, specific properties can be set for them overriding the defaults.
Version:

$Id: ToStringTransformer.java 205 2012-01-29 18:29:57Z oheger $

Author:

Oliver Heger

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`PROP_DATE_FORMAT_STYLE` Constant for the date format style property.
`static String`	`PROP_GROUPING_USED` Constant for the grouping used property.
`static String`	`PROP_MAXIMUM_FRACTION_DIGITS` Constant for the maximum fraction digits property.
`static String`	`PROP_MINIMUM_FRACTION_DIGITS` Constant for the minimum fraction digits property.

Constructor Summary

Constructors
Constructor and Description

ToStringTransformer()
Creates a new instance of ToStringTransformer.

Constructors
Constructor and Description
`ToStringTransformer()` Creates a new instance of `ToStringTransformer`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`getDateFormatStyle()` Returns the style to be used for formatting dates.
`int`	`getMaximumFractionDigits()` Returns the maximum number of fraction digits.
`int`	`getMinimumFractionDigits()` Returns the minimum number of fraction digits.
`protected boolean`	`isDecimalNumber(Object o)` Checks whether the passed in object is a decimal number.
`boolean`	`isGroupingUsed()` Returns a flag whether a grouping character is to be used when formatting numbers.
`protected boolean`	`isIntegerNumber(Object o)` Checks whether the passed in object is an integer number.
`void`	`setDateFormatStyle(int dateFormatStyle)` Sets the style to be used for formatting dates.
`void`	`setGroupingUsed(boolean groupingUsed)` Sets the grouping used flag.
`void`	`setMaximumFractionDigits(int maximumFractionDigits)` Sets the maximum number of fraction digits.
`void`	`setMinimumFractionDigits(int minimumFractionDigits)` Sets the minimum number of fraction digits.
`Object`	`transform(Object o, TransformerContext ctx)` Transforms the specified object.
`protected Object`	`transformDate(Date dt, TransformerContext ctx)` Transforms a date object.
`protected Object`	`transformDecimalNumber(Object number, TransformerContext ctx)` Transforms a decimal number object.
`protected Object`	`transformIntegerNumber(Object number, TransformerContext ctx)` Transforms an integer number object.
`protected Object`	`transformNull(TransformerContext ctx)` Transforms a null object.
`protected Object`	`transformObject(Object o, TransformerContext ctx)` Transforms an arbitrary object.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - PROP_DATE_FORMAT_STYLE
```
public static final String PROP_DATE_FORMAT_STYLE
```
    Constant for the date format style property.
    
    See Also:
    
    Constant Field Values
  - PROP_MAXIMUM_FRACTION_DIGITS
```
public static final String PROP_MAXIMUM_FRACTION_DIGITS
```
    Constant for the maximum fraction digits property.
    
    See Also:
    
    Constant Field Values
  - PROP_MINIMUM_FRACTION_DIGITS
```
public static final String PROP_MINIMUM_FRACTION_DIGITS
```
    Constant for the minimum fraction digits property.
    
    See Also:
    
    Constant Field Values
  - PROP_GROUPING_USED
```
public static final String PROP_GROUPING_USED
```
    Constant for the grouping used property.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - ToStringTransformer
```
public ToStringTransformer()
```
    Creates a new instance of ToStringTransformer.
- Method Detail
  - getDateFormatStyle
```
public int getDateFormatStyle()
```
    Returns the style to be used for formatting dates.
    
    Returns:
    
    the style for the formatting of dates
  - setDateFormatStyle
```
public void setDateFormatStyle(int dateFormatStyle)
```
    Sets the style to be used for formatting dates. This is one of the style constants defined by the java.text.DateFormat class.
    
    Parameters:
    
    dateFormatStyle - the style to be used
  - getMinimumFractionDigits
```
public int getMinimumFractionDigits()
```
    Returns the minimum number of fraction digits.
    
    Returns:
    
    the minimum number of fraction digits
  - setMinimumFractionDigits
```
public void setMinimumFractionDigits(int minimumFractionDigits)
```
    Sets the minimum number of fraction digits. This value is taken into account when formatting decimal numbers.
    
    Parameters:
    
    minimumFractionDigits - the new minimum number of fraction digits
  - getMaximumFractionDigits
```
public int getMaximumFractionDigits()
```
    Returns the maximum number of fraction digits.
    
    Returns:
    
    the maximum number of fraction digits
  - setMaximumFractionDigits
```
public void setMaximumFractionDigits(int maximumFractionDigits)
```
    Sets the maximum number of fraction digits. This value is taken into account when formatting decimal numbers.
    
    Parameters:
    
    maximumFractionDigits - the new maximum number of fraction digits
  - isGroupingUsed
```
public boolean isGroupingUsed()
```
    Returns a flag whether a grouping character is to be used when formatting numbers.
    
    Returns:
    
    the grouping flag
  - setGroupingUsed
```
public void setGroupingUsed(boolean groupingUsed)
```
    Sets the grouping used flag. When formatting numbers this flag controls whether a grouping character is used for big numbers.
    
    Parameters:
    
    groupingUsed - the grouping flag
  - transform
```
public Object transform(Object o,
                        TransformerContext ctx)
                 throws Exception
```
    Transforms the specified object. Depending on the type of the object one of the specialized transform methods will be called.
    
    Specified by:
    
    transform in interface Transformer
    
    Parameters:
    
    o - the object to be transformed
    
    ctx - the transformer context
    
    Returns:
    
    the transformed object
    
    Throws:
    
    Exception - if an error occurs
  - transformNull
```
protected Object transformNull(TransformerContext ctx)
                        throws Exception
```
    Transforms a null object. This implementation returns an empty string.
    
    Parameters:
    
    ctx - the transformer context
    
    Returns:
    
    the transformed object
    
    Throws:
    
    Exception - if an error occurs
  - transformDate
```
protected Object transformDate(Date dt,
                               TransformerContext ctx)
                        throws Exception
```
    Transforms a date object. This implementation uses a date format object.
    
    Parameters:
    
    dt - the date to be formatted
    
    ctx - the transformer context
    
    Returns:
    
    the transformed object
    
    Throws:
    
    Exception - if an error occurs
  - transformDecimalNumber
```
protected Object transformDecimalNumber(Object number,
                                        TransformerContext ctx)
                                 throws Exception
```
    Transforms a decimal number object. This implementation uses a number format object.
    
    Parameters:
    
    number - the number object to be formatted
    
    ctx - the transformer context
    
    Returns:
    
    the transformed object
    
    Throws:
    
    Exception - if an error occurs
  - transformIntegerNumber
```
protected Object transformIntegerNumber(Object number,
                                        TransformerContext ctx)
                                 throws Exception
```
    Transforms an integer number object. For this purpose a number format object is used.
    
    Parameters:
    
    number - the number to be transformed
    
    ctx - the transformer context
    
    Returns:
    
    the transformed object
    
    Throws:
    
    Exception - if an error occurs
  - transformObject
```
protected Object transformObject(Object o,
                                 TransformerContext ctx)
                          throws Exception
```
    Transforms an arbitrary object. This method is invoked if no other, more specific transformation method can be found. It transforms the object into a string by invoking its toString() method.
    
    Parameters:
    
    o - the object to be transformed
    
    ctx - the transformer context
    
    Returns:
    
    the transformed object
    
    Throws:
    
    Exception - if an error occurs
  - isDecimalNumber
```
protected boolean isDecimalNumber(Object o)
```
    Checks whether the passed in object is a decimal number. This implementation checks for the typical Java types representing decimal numbers.
    
    Parameters:
    
    o - the object to check
    
    Returns:
    
    a flag whether the passed in object is a decimal number
  - isIntegerNumber
```
protected boolean isIntegerNumber(Object o)
```
    Checks whether the passed in object is an integer number. This implementation simply checks whether the object is an instance of java.lang.Number. Because decimal numbers are checked first, the remaining number objects are integers.
    
    Parameters:
    
    o - the object to check
    
    Returns:
    
    a flag whether this object is an integer number

Class ToStringTransformer

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PROP_DATE_FORMAT_STYLE

PROP_MAXIMUM_FRACTION_DIGITS

PROP_MINIMUM_FRACTION_DIGITS

PROP_GROUPING_USED

Constructor Detail

ToStringTransformer

Method Detail

getDateFormatStyle

setDateFormatStyle

getMinimumFractionDigits

setMinimumFractionDigits

getMaximumFractionDigits

setMaximumFractionDigits

isGroupingUsed

setGroupingUsed

transform

transformNull

transformDate

transformDecimalNumber

transformIntegerNumber

transformObject

isDecimalNumber

isIntegerNumber