jidefx.utils.converter

Class EnumConverter<T>

java.lang.Object

javafx.util.StringConverter<T>

jidefx.utils.converter.DefaultObjectConverter<T>

jidefx.utils.converter.EnumConverter<T>

All Implemented Interfaces:

LazyInitializeConverter, ObjectConverter<T>

public class EnumConverter<T>
extends DefaultObjectConverter<T>
implements LazyInitializeConverter

EnumConverter is a converter for Enums or any other data type that can be enumerated. If it is an Enum, you can use EnumConverter(Class) to create a converter. For other data types, you can use other constructors.

Before JDK1.5, there is no Enum type, so this is only one way to define an enumeration. For example, in SwingConstants, the following values are defined.

 public static final int CENTER  = 0;
 public static final int TOP     = 1;
 public static final int LEFT    = 2;
 public static final int BOTTOM  = 3;
 public static final int RIGHT   = 4;
 

The problem comes when you want to display it in UI. You don't want to use 0, 1, 2, 3, 4 as the value doesn't mean anything from user point of view. You want to use a more meaningful name such as "Center", "Top", "Left", "Bottom", "Right". Obviously you need a converter here to convert from the integer to string, such as converting from 0 to "Center" and vice verse. That's what EnumConverter for.

Constructor Summary

Constructors

Constructor and Description
EnumConverter() Creates an empty EnumConverter.
EnumConverter(java.lang.Class<? extends java.lang.Enum> enumType) The constructor to create an EnumConverter for an Enum type.
EnumConverter(java.lang.String name, java.lang.Class<?> type, T[] values, java.lang.String[] strings) Creates an EnumConverter.
EnumConverter(java.lang.String name, java.lang.Class<?> type, T[] values, java.lang.String[] strings, T defaultValue) Creates an EnumConverter.
EnumConverter(java.lang.String name, T[] values, java.lang.String[] strings) Creates an EnumConverter.

Method Summary

Modifier and Type	Method and Description
T	fromString(java.lang.String string, ConverterContext context) Converts the string to the object.
ConverterContext	getConverterContext() Gets the converter context of this converter.
T	getDefault() Gets the default value of the converter if it failed to find the matching object for a particular string.
java.lang.String	getName() Gets the name of the converter.
java.lang.Object[]	getObjects() Gets the objects array.
java.lang.String[]	getStrings() Gets the strings array.
java.lang.Class<?>	getType() Gets the data type of the converter.
void	initialize(java.lang.Class<?> clazz, ConverterContext converterContext) Initialize the converter.
java.lang.String	toString(T value, ConverterContext context) Converts the object to string.
static java.lang.String[]	toStrings(java.lang.Object[] values) Converts an object array to a String array using ObjectConverterManager.
static java.lang.String[]	toStrings(java.lang.Object[] values, ConverterContext converterContext) Converts an object array to a String array using ObjectConverterManager.

Methods inherited from class jidefx.utils.converter.DefaultObjectConverter

fromString, getObjectConverterManager, toString, toStringConverter

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

EnumConverter

public EnumConverter()

Creates an empty EnumConverter. It can be initialized later using initialize(Class, ConverterContext) method.

EnumConverter

public EnumConverter(java.lang.Class<? extends java.lang.Enum> enumType)

The constructor to create an EnumConverter for an Enum type.

Parameters:

enumType - the enum type

EnumConverter

public EnumConverter(java.lang.String name,
                     T[] values,
                     java.lang.String[] strings)

Creates an EnumConverter. The type is set to the type of the first element in the value array. The default value is set to the first element in the value array.

Parameters:

name - the name of the converter. The name is used to create ConverterContext and later on the EditorContext.

values - the value array. All elements in the value array should have the same type and it must have at last one element in the array.

strings - the names array. It contains the meaningful names for the elements in the value array. They should one to one match with each other. The length of name array should be the same as that of value array. Otherwise IllegalArgumentException will be thrown.

EnumConverter

public EnumConverter(java.lang.String name,
                     java.lang.Class<?> type,
                     T[] values,
                     java.lang.String[] strings)

Creates an EnumConverter. The default value is set to the first element in the value array.

Parameters:

name - the name of the converter. The name is used to create ConverterContext and later on the EditorContext.

type - the type of the element in value array.

values - the value array. All elements in the value array should have the same type and it must have at last one element in the array.

strings - the names array. It contains the meaningful names for the elements in the value array. They should one to one match with each other. The length of name array should be the same as that of value array. Otherwise IllegalArgumentException will be thrown.

EnumConverter

public EnumConverter(java.lang.String name,
                     java.lang.Class<?> type,
                     T[] values,
                     java.lang.String[] strings,
                     T defaultValue)

Creates an EnumConverter.

Parameters:

name - the name of the converter. The name is used to create ConverterContext and later on the EditorContext.

type - the type of the element in value array.

values - the value array. All elements in the value array should have the same type and it must have at last one element in the array.

strings - the names array. It contains the meaningful names for the elements in the value array. They should one to one match with each other. The length of name array should be the same as that of value array. Otherwise IllegalArgumentException will be thrown.

defaultValue - the default value

Method Detail

initialize

public void initialize(java.lang.Class<?> clazz,
                       ConverterContext converterContext)

Description copied from interface: LazyInitializeConverter

Initialize the converter. This method will be called by ObjectConverterManager in the getConverter method.

Specified by:

initialize in interface LazyInitializeConverter

Parameters:

clazz - the actual data type.

converterContext - the actual converter context.

getConverterContext

public ConverterContext getConverterContext()

Gets the converter context of this converter. The name of the context is the name of the converter where you pass in to EnumConverter's constructor.

Returns:

the converter context of this converter.

toString

public java.lang.String toString(T value,
                                 ConverterContext context)

Converts the object to string. It will find the object from the value array and find the matching string from strings array. An empty string will be returned if nothing matches. Otherwise, it will return the corresponding string.

Specified by:

toString in interface ObjectConverter<T>

Overrides:

toString in class DefaultObjectConverter<T>

Parameters:

value - the object to be converted.

context - the converter context.

Returns:

the string for the object.

fromString

public T fromString(java.lang.String string,
                    ConverterContext context)

Converts the string to the object. It will find the string from the strings array and find the matching object from the value array. The default value will be returned if nothing matches. Otherwise, it will return the string itself that is passed in.

Specified by:

fromString in interface ObjectConverter<T>

Overrides:

fromString in class DefaultObjectConverter<T>

Parameters:

string - the string to be converted

context - the converter context.

Returns:

the object of the string.

getName

public java.lang.String getName()

Gets the name of the converter.

Returns:

the name of the converter.

getType

public java.lang.Class<?> getType()

Gets the data type of the converter.

Returns:

the data type of the converter.

getDefault

public T getDefault()

Gets the default value of the converter if it failed to find the matching object for a particular string.

Returns:

the default value.

getObjects

public java.lang.Object[] getObjects()

Gets the objects array.

Returns:

the objects array.

getStrings

public java.lang.String[] getStrings()

Gets the strings array.

Returns:

the strings array.

toStrings

public static java.lang.String[] toStrings(java.lang.Object[] values)

Converts an object array to a String array using ObjectConverterManager.

This method can be used, for example, for Enum type, to provide a default string representation of the enum values.

 ObjectConverter converter = new EnumConverter("Rank", Rank.values(),
 EnumConverter.toStrings(Rank.values()));
 

Of course, you can still define your own string array for the enum values if the default one doesn't work well.

Parameters:

values - the object array.

Returns:

the string array.

toStrings

public static java.lang.String[] toStrings(java.lang.Object[] values,
                                           ConverterContext converterContext)

Converts an object array to a String array using ObjectConverterManager.

Parameters:

values - the object array.

converterContext - the converter context used when calling ObjectConverterManager.toString.

Returns:

the string array.