org.yarnandtail.andhow.api

Interface ValueType<T>

All Known Implementing Classes:

BaseValueType, DblType, FlagType, IntType, LngType, LocalDateTimeType, StrType

public interface ValueType<T>

The type of a Property. Also handles parsing and casting of Strings and Objects to the destination type represented by an instance of a ValueType.

Author:

eeverman

Method Summary

Modifier and Type	Method and Description
T	cast(Object o) Attempt to cast the passed object to the generic type T.
Class<T>	getDestinationType()
boolean	isParsable(String sourceValue) Returns true if the string can safely be parsed into the destination type by the parse() method.
T	parse(String sourceValue) Attempts to parse the passed String into the destinationType.
String	toString(T value) Converts an instance of the destination type to string.

Method Detail

getDestinationType

Class<T> getDestinationType()

parse

T parse(String sourceValue)
 throws ParsingException

Attempts to parse the passed String into the destinationType. All trimming (removing whitespace from around a value) should be assumed to already have happened for the incoming sourceValue by a Trimmer. Implementations should be careful to ONLY throw a ParsingException - Integers and other types may throw other unchecked exceptions when trying to convert values, which should be handled in this method and rethrown as a ParsingException. This method and toString(T) should be reversible: The object generated here should be toString-able to a String equal to the one passed this method.

Parameters:

sourceValue -

Returns:

null if null, or a value of type T

Throws:

ParsingException - for any type of failure.

toString

String toString(T value)

Converts an instance of the destination type to string. For most types, simply calling T.toString() is a good enough implementation. For dates, times and other more complex types, more detailed conversion may be needed. This method and parse() should be reversible: The string generated here should be parsable to an object equal to the one passed this methond.

Parameters:

value -

Returns:

null if the passed value is null.

isParsable

boolean isParsable(String sourceValue)

Returns true if the string can safely be parsed into the destination type by the parse() method.

Parameters:

sourceValue -

Returns:

true or false - this should never throw an exception.

cast

T cast(Object o)
throws RuntimeException

Attempt to cast the passed object to the generic type T. AndHow uses this internally to cast values known to already be of type T, but were stored in a generic way. If used for unknown types that are not castable to T, it will throw a RuntimeException.

Parameters:

o -

Returns:

Throws:

RuntimeException