Package org.springframework.expression
Interface TypeConverter
- All Known Implementing Classes:
StandardTypeConverter
public interface TypeConverter
A type converter can convert values between different types encountered during expression evaluation. This is an SPI for the expression parser; seeConversionService
for the primary user API to Spring's conversion facilities.- Since:
- 3.0
- Author:
- Andy Clement, Juergen Hoeller
Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description boolean
canConvert(TypeDescriptor sourceType, TypeDescriptor targetType)
Returntrue
if the type converter can convert the specified type to the desired target type.Object
convertValue(Object value, TypeDescriptor sourceType, TypeDescriptor targetType)
Convert (or coerce) a value from one type to another, for example from aboolean
to aString
.
Method Detail
canConvert
boolean canConvert(@Nullable TypeDescriptor sourceType, TypeDescriptor targetType)
Returntrue
if the type converter can convert the specified type to the desired target type.- Parameters:
sourceType
- a type descriptor that describes the source typetargetType
- a type descriptor that describes the requested result type- Returns:
true
if that conversion can be performed
convertValue
@Nullable Object convertValue(@Nullable Object value, @Nullable TypeDescriptor sourceType, TypeDescriptor targetType)
Convert (or coerce) a value from one type to another, for example from aboolean
to aString
.The
TypeDescriptor
parameters enable support for typed collections: A caller may prefer aList<Integer>
, for example, rather than simply anyList
.- Parameters:
value
- the value to be convertedsourceType
- a type descriptor that supplies extra information about the source objecttargetType
- a type descriptor that supplies extra information about the requested result type- Returns:
- the converted value
- Throws:
EvaluationException
- if conversion failed or is not possible to begin with