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; see
ConversionService
for the primary
user API to Spring's conversion facilities.- Since:
- 3.0
- Author:
- Andy Clement, Juergen Hoeller
-
Method Summary
Modifier and TypeMethodDescriptionboolean
canConvert
(TypeDescriptor sourceType, TypeDescriptor targetType) Returntrue
if the type converter can convert the specified type to the desired target type.convertValue
(Object value, TypeDescriptor sourceType, TypeDescriptor targetType) Convert (or coerce) a value from one type to another, for example from aboolean
to aString
.
-
Method Details
-
canConvert
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
-