org.apache.cocoon.forms.datatype
Interface Datatype

All Known Implementing Classes:

AbstractDatatype, BeanType, BooleanType, CharType, DateType, DecimalType, DoubleType, EnumType, FloatType, IntegerType, LongType, StringType

public interface Datatype

A Datatype encapsulates the functionality for working with specific kinds of data like integers, decimals or dates.

It provides:

• Methods for converting between String and Object representation of the data
• For validating the data (usually against a set of validation rules)
• optionally a selection list

Each datatype can be marked as an "arraytype". Currently, this only has an influence on the validate(Object, ExpressionContext) method, which should in that case be passed an array of objects. See also isArrayType().

Version:

$Id: Datatype.html 1304258 2012-03-23 10:09:27Z ilgrosso $

Method Summary

ConversionResult	convertFromString(String value, Locale locale) Converts a string to an object of this datatype.
String	convertToString(Object value, Locale locale) Converts an object of this datatype to a string representation.
void	generateSaxFragment(ContentHandler contentHandler, Locale locale) Generates a bit of information about this datatype.
DatatypeBuilder	getBuilder() Returns the factory that built this datatype.
Convertor	getConvertor() Returns the convertor used by this datatype.
String	getDescriptiveName() Returns a descriptive name for the base type of this datatype, i.e. something like 'string', 'long', 'decimal', ...
Convertor	getPlainConvertor() Returns the "plain convertor".
Class	getTypeClass() Gets the class object for the type represented by this datatype.
boolean	isArrayType() Indicates wether this datatype represents an array type.
ValidationError	validate(Object value, org.outerj.expression.ExpressionContext expressionContext) Returns null if validation is successful, otherwise returns a ValidationError instance.

Method Detail

convertFromString

ConversionResult convertFromString(String value,
                                   Locale locale)

Converts a string to an object of this datatype. This method uses the same Convertor as returned by the getConvertor() method.

convertToString

String convertToString(Object value,
                       Locale locale)

Converts an object of this datatype to a string representation. This method uses the same Convertor as returned by the getConvertor() method.

validate

ValidationError validate(Object value,
                         org.outerj.expression.ExpressionContext expressionContext)

Returns null if validation is successful, otherwise returns a ValidationError instance.

Parameters:

value - an Object of the correct type for this datatype (see getTypeClass(), or if isArrayType() returns true, an array of objects of that type.

getTypeClass

Class getTypeClass()

Gets the class object for the type represented by this datatype. E.g. Long, String, ... The objects returned from the convertFromString* methods are of this type, and the object passed to the convertToString* or validate methods should be of this type.

getDescriptiveName

String getDescriptiveName()

Returns a descriptive name for the base type of this datatype, i.e. something like 'string', 'long', 'decimal', ...

isArrayType

boolean isArrayType()

Indicates wether this datatype represents an array type. This approach has been chosen instead of creating a seperate ArrayDatatype interface (and corresponding implementations), since almost all functionality is the same between the scalar and array types. The main difference is that the validate() method will be passed arrays instead of single values, and hence different validation rules will be required.

getConvertor

Convertor getConvertor()

Returns the convertor used by this datatype.

getPlainConvertor

Convertor getPlainConvertor()

Returns the "plain convertor". This is convertor that should have a locale-independent string encoding, and guarantees perfect roundtripping. It is used if a value of this datatype needs to be stored but not displayed to the user.

getBuilder

DatatypeBuilder getBuilder()

Returns the factory that built this datatype.

generateSaxFragment

void generateSaxFragment(ContentHandler contentHandler,
                         Locale locale)
                         throws SAXException

Generates a bit of information about this datatype.

Throws:

SAXException