Package org.springframework.core.convert.support

Class GenericConversionService

java.lang.Object
org.springframework.core.convert.support.GenericConversionService
All Implemented Interfaces:
ConversionService, ConverterRegistry, ConfigurableConversionService
Direct Known Subclasses:
DefaultConversionService, FormattingConversionService
public class GenericConversionService extends 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, Phillip Webb, David Haraburda

  • Constructor Details

    • GenericConversionService

      public GenericConversionService()

  • Method Details

    • addConverter

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

    • addConverter

      public <S, T> void addConverter(Class<S> sourceType, Class<T> targetType, Converter<? super S,? extends T> converter)
      Description copied from interface: ConverterRegistry
      Add a plain converter to this registry. The convertible source/target type 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<?,?> factory)
      Description copied from interface: ConverterRegistry
      Add a ranged converter factory to this registry. The convertible source/target type pair is derived from the ConverterFactory's parameterized types.
      Specified by:
      addConverterFactory in interface ConverterRegistry

    • removeConvertible

      public void removeConvertible(Class<?> sourceType, 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(@Nullable Class<?> sourceType, Class<?> targetType)
      Description copied from interface: ConversionService
      Return true if objects of sourceType can be converted to the 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(@Nullable TypeDescriptor sourceType, TypeDescriptor targetType)
      Description copied from interface: ConversionService
      Return 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

    • canBypassConvert

      public boolean canBypassConvert(@Nullable TypeDescriptor sourceType, TypeDescriptor targetType)
      Return whether conversion between the source type and the target type can be bypassed.

      More precisely, this method will return true if objects of sourceType can be converted to the target type by returning the source object unchanged.

      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 conversion can be bypassed; false otherwise
      Throws:
      IllegalArgumentException - if targetType is null
      Since:
      3.2

    • convert

      @Nullable public <T> T convert(@Nullable Object source, Class<T> targetType)
      Description copied from interface: ConversionService
      Convert the given source to the specified 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

      @Nullable public Object convert(@Nullable Object source, @Nullable TypeDescriptor sourceType, TypeDescriptor targetType)
      Description copied from interface: ConversionService
      Convert the given source to the specified 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 to convert 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

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • convertNullSource

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

      The default implementation returns null or the Java 8 Optional.empty() instance if the target type is java.util.Optional. Subclasses may override this to return custom null objects for specific target types.

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

    • getConverter

      @Nullable protected GenericConverter getConverter(TypeDescriptor sourceType, TypeDescriptor targetType)
      Hook method to look up 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.
      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

      @Nullable 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 source type is assignable to the target type. Returns null otherwise, indicating no suitable converter could be found.

      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