cascading.tuple.type
Interface CoercibleType<Canonical>

All Superinterfaces:
Serializable, Type
All Known Implementing Classes:
BigDecimalCoerce, BooleanCoerce, BooleanObjectCoerce, CharacterCoerce, CharacterObjectCoerce, Coercions.Coerce, DateType, DoubleCoerce, DoubleObjectCoerce, FloatCoerce, FloatObjectCoerce, IntegerCoerce, IntegerObjectCoerce, LongCoerce, LongObjectCoerce, ObjectCoerce, ShortCoerce, ShortObjectCoerce, StringCoerce

public interface CoercibleType<Canonical>
extends Type, Serializable

Interface CoercibleType allows Fields instances to be extended with custom type information.

It is the role of implementations of this interface to maintain a canonical representation of a given value and to allow for coercions between some type representation to the canonical type and back.

For example, if a field in a text delimited file is a date, ie. 28/Dec/2012:16:17:12:931 -0800 it may be beneficial for the internal representation to be a Long value for performance reasons.

Note CoercibleType used in conjunction with the TextDelimited parsers is not a replacement for using a pipe assembly to cleanse data. Pushing data cleansing down to a Tap and Scheme may not provide the flexibility and robustness expected.

CoercibleTypes are a convenience when the input data is of high quality or was previously written out using a CoercibleType instance.

The CoercibleTypes further allow the Cascading planner to perform type checks during joins. If no Comparator is in use, and lhs and rhs fields are not the same type, the planner will throw an exception.


Method Summary
 Canonical canonical(Object value)
           
<Coerce> Coerce
coerce(Object value, Type to)
           
 Class<Canonical> getCanonicalType()
           
 

Method Detail

getCanonicalType

Class<Canonical> getCanonicalType()
Returns:
the actual Java type this CoercibleType represents

canonical

Canonical canonical(Object value)
Parameters:
value - of type Object
Returns:
the value coerced into its canonical type

coerce

<Coerce> Coerce coerce(Object value,
                       Type to)
Parameters:
value - of type Object
to - of type Type
Returns:
the value coerced into the requested type


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