Spring Framework

org.springframework.core.convert.support
Class GenericConversionService

java.lang.Object
  extended by org.springframework.core.convert.support.GenericConversionService
All Implemented Interfaces:
ConversionService, ConverterRegistry, ConfigurableConversionService
Direct Known Subclasses:
DefaultConversionService, FormattingConversionService

public class GenericConversionService
extends java.lang.Object
implements ConfigurableConversionService

Base ConversionService implementation suitable for use in most environments. Indirectly implements ConverterRegistry as registration API through the ConfigurableConversionService interface.

Since:
3.0
Author:
Keith Donald, Juergen Hoeller, Chris Beams

Constructor Summary
GenericConversionService()
           
 
Method Summary
 void addConverter(java.lang.Class<?> sourceType, java.lang.Class<?> targetType, Converter<?,?> converter)
          Add a plain converter to this registry.
 void addConverter(Converter<?,?> converter)
          Add a plain converter to this registry.
 void addConverter(GenericConverter converter)
          Add a generic converter to this registry.
 void addConverterFactory(ConverterFactory<?,?> converterFactory)
          Add a ranged converter factory to this registry.
 boolean canConvert(java.lang.Class<?> sourceType, java.lang.Class<?> targetType)
          Returns true if objects of sourceType can be converted to targetType.
 boolean canConvert(TypeDescriptor sourceType, TypeDescriptor targetType)
          Returns true if objects of sourceType can be converted to the targetType.
<T> T
convert(java.lang.Object source, java.lang.Class<T> targetType)
          Convert the source to targetType.
 java.lang.Object convert(java.lang.Object source, TypeDescriptor targetType)
          Convenience operation for converting a source object to the specified targetType, where the targetType is a descriptor that provides additional conversion context.
 java.lang.Object convert(java.lang.Object source, TypeDescriptor sourceType, TypeDescriptor targetType)
          Convert the source to targetType.
protected  java.lang.Object convertNullSource(TypeDescriptor sourceType, TypeDescriptor targetType)
          Template method to convert a null source.
protected  GenericConverter getConverter(TypeDescriptor sourceType, TypeDescriptor targetType)
          Hook method to lookup the converter for a given sourceType/targetType pair.
protected  GenericConverter getDefaultConverter(TypeDescriptor sourceType, TypeDescriptor targetType)
          Return the default converter if no converter is found for the given sourceType/targetType pair.
 void removeConvertible(java.lang.Class<?> sourceType, java.lang.Class<?> targetType)
          Remove any converters from sourceType to targetType.
 java.lang.String toString()
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

GenericConversionService

public GenericConversionService()
Method Detail

addConverter

public void addConverter(Converter<?,?> converter)
Description copied from interface: ConverterRegistry
Add a plain converter to this registry. The convertible sourceType/targetType pair is derived from the Converter's parameterized types.

Specified by:
addConverter in interface ConverterRegistry

addConverter

public void addConverter(java.lang.Class<?> sourceType,
                         java.lang.Class<?> targetType,
                         Converter<?,?> converter)
Description copied from interface: ConverterRegistry
Add a plain converter to this registry. The convertible sourceType/targetType pair is specified explicitly. Allows for a Converter to be reused for multiple distinct pairs without having to create a Converter class for each pair.

Specified by:
addConverter in interface ConverterRegistry

addConverter

public void addConverter(GenericConverter converter)
Description copied from interface: ConverterRegistry
Add a generic converter to this registry.

Specified by:
addConverter in interface ConverterRegistry

addConverterFactory

public void addConverterFactory(ConverterFactory<?,?> converterFactory)
Description copied from interface: ConverterRegistry
Add a ranged converter factory to this registry. The convertible sourceType/rangeType pair is derived from the ConverterFactory's parameterized types.

Specified by:
addConverterFactory in interface ConverterRegistry

removeConvertible

public void removeConvertible(java.lang.Class<?> sourceType,
                              java.lang.Class<?> targetType)
Description copied from interface: ConverterRegistry
Remove any converters from sourceType to targetType.

Specified by:
removeConvertible in interface ConverterRegistry
Parameters:
sourceType - the source type
targetType - the target type

canConvert

public boolean canConvert(java.lang.Class<?> sourceType,
                          java.lang.Class<?> targetType)
Description copied from interface: ConversionService
Returns true if objects of sourceType can be converted to targetType. If this method returns true, it means ConversionService.convert(Object, Class) is capable of converting an instance of sourceType to targetType. Special note on collections, arrays, and maps types: For conversion between collection, array, and map types, this method will return 'true' even though a convert invocation may still generate a ConversionException if the underlying elements are not convertible. Callers are expected to handle this exceptional case when working with collections and maps.

Specified by:
canConvert in interface ConversionService
Parameters:
sourceType - the source type to convert from (may be null if source is null)
targetType - the target type to convert to (required)
Returns:
true if a conversion can be performed, false if not

canConvert

public boolean canConvert(TypeDescriptor sourceType,
                          TypeDescriptor targetType)
Description copied from interface: ConversionService
Returns true if objects of sourceType can be converted to the targetType. The TypeDescriptors provide additional context about the source and target locations where conversion would occur, often object fields or property locations. If this method returns true, it means ConversionService.convert(Object, TypeDescriptor, TypeDescriptor) is capable of converting an instance of sourceType to targetType. Special note on collections, arrays, and maps types: For conversion between collection, array, and map types, this method will return 'true' even though a convert invocation may still generate a ConversionException if the underlying elements are not convertible. Callers are expected to handle this exceptional case when working with collections and maps.

Specified by:
canConvert in interface ConversionService
Parameters:
sourceType - context about the source type to convert from (may be null if source is null)
targetType - context about the target type to convert to (required)
Returns:
true if a conversion can be performed between the source and target types, false if not

convert

public <T> T convert(java.lang.Object source,
                     java.lang.Class<T> targetType)
Description copied from interface: ConversionService
Convert the source to targetType.

Specified by:
convert in interface ConversionService
Parameters:
source - the source object to convert (may be null)
targetType - the target type to convert to (required)
Returns:
the converted object, an instance of targetType

convert

public java.lang.Object convert(java.lang.Object source,
                                TypeDescriptor sourceType,
                                TypeDescriptor targetType)
Description copied from interface: ConversionService
Convert the source to targetType. The TypeDescriptors provide additional context about the source and target locations where conversion will occur, often object fields or property locations.

Specified by:
convert in interface ConversionService
Parameters:
source - the source object to convert (may be null)
sourceType - context about the source type converting from (may be null if source is null)
targetType - context about the target type to convert to (required)
Returns:
the converted object, an instance of targetType

convert

public java.lang.Object convert(java.lang.Object source,
                                TypeDescriptor targetType)
Convenience operation for converting a source object to the specified targetType, where the targetType is a descriptor that provides additional conversion context. Simply delegates to convert(Object, TypeDescriptor, TypeDescriptor) and encapsulates the construction of the sourceType descriptor using TypeDescriptor.forObject(Object).

Parameters:
source - the source object
targetType - the target type
Returns:
the converted value
Throws:
ConversionException - if a conversion exception occurred
java.lang.IllegalArgumentException - if targetType is null
java.lang.IllegalArgumentException - if sourceType is null but source is not null

toString

public java.lang.String toString()
Overrides:
toString in class java.lang.Object

convertNullSource

protected java.lang.Object convertNullSource(TypeDescriptor sourceType,
                                             TypeDescriptor targetType)
Template method to convert a null source.

Default implementation returns null. Subclasses may override to return custom null objects for specific target types.

Parameters:
sourceType - the sourceType to convert from
targetType - the targetType to convert to
Returns:
the converted null object

getConverter

protected GenericConverter getConverter(TypeDescriptor sourceType,
                                        TypeDescriptor targetType)
Hook method to lookup the converter for a given sourceType/targetType pair. First queries this ConversionService's converter cache. On a cache miss, then performs an exhaustive search for a matching converter. If no converter matches, returns the default converter. Subclasses may override.

Parameters:
sourceType - the source type to convert from
targetType - the target type to convert to
Returns:
the generic converter that will perform the conversion, or null if no suitable converter was found
See Also:
getDefaultConverter(TypeDescriptor, TypeDescriptor)

getDefaultConverter

protected GenericConverter getDefaultConverter(TypeDescriptor sourceType,
                                               TypeDescriptor targetType)
Return the default converter if no converter is found for the given sourceType/targetType pair. Returns a NO_OP Converter if the sourceType is assignable to the targetType. Returns null otherwise, indicating no suitable converter could be found. Subclasses may override.

Parameters:
sourceType - the source type to convert from
targetType - the target type to convert to
Returns:
the default generic converter that will perform the conversion

Spring Framework