cz.auderis.tools.config

Interface DataTranslator

All Known Implementing Classes:

BigDecimalTranslator, BigIntegerTranslator, ClassTranslator, CurrencyTranslator, EnumSetTranslator, InetAddressTranslator, PatternTranslator, SingleTargetClassTranslator, UuidTranslator

public interface DataTranslator

DataTranslator defines a mechanism by which an arbitrary object is translated into an instance of a given class. Classes implementing this interface are discovered using standard ServiceLoader.

Version:

1.0

Author:

Boleslav Bobcik <bbobcik@gmail.com>

Field Summary

Fields

Modifier and Type	Field and Description
static Object	NULL_OBJECT This constant allows the translator to indicate that the result value is null, which normally means unsuccessful translation, causing further attempts of translation.
static int	PRIORITY_NORMAL_SUPPORT The default priority means that a class is supported by this translator.
static int	PRIORITY_NOT_SUPPORTED Priority 0 denotes that a class is not supported by this translator.

Method Summary

Modifier and Type	Method and Description
String	getId() Gets an identifier of this translator.
int	getTargetClassSupportPriority(Class<?> targetClass, DataTranslatorContext context) Determines whether the argument represents a class supported by this translator.
Object	translateToClass(Object source, Class<?> targetClass, DataTranslatorContext context) Attempts to translate an arbitrary object into an instance of targetClass.

Field Detail

PRIORITY_NOT_SUPPORTED

static final int PRIORITY_NOT_SUPPORTED

Priority 0 denotes that a class is not supported by this translator.

See Also:

getTargetClassSupportPriority(Class, DataTranslatorContext), Constant Field Values

PRIORITY_NORMAL_SUPPORT

static final int PRIORITY_NORMAL_SUPPORT

The default priority means that a class is supported by this translator.

See Also:

getTargetClassSupportPriority(Class, DataTranslatorContext), Constant Field Values

NULL_OBJECT

static final Object NULL_OBJECT

This constant allows the translator to indicate that the result value is null, which normally means unsuccessful translation, causing further attempts of translation.

Method Detail

getId

String getId()

Gets an identifier of this translator. The identifier may be used for diagnostic purposes.

Returns:

id of this translator

getTargetClassSupportPriority

int getTargetClassSupportPriority(Class<?> targetClass,
                                  DataTranslatorContext context)

Determines whether the argument represents a class supported by this translator. Positive values mean that the class is supported. Unsupported classes are typically represented by PRIORITY_NOT_SUPPORTED constant.

The translator that reports the highest priority will be used for the actual translation. If there are multiple translators with the same maximum priority, the choice will be arbitrary.

Parameters:

targetClass - class of the expected result of translation

context - context of the translation

Returns:

positive value if this translator is able to handle targetClass; zero or negative value if the class is not supported

translateToClass

Object translateToClass(Object source,
                        Class<?> targetClass,
                        DataTranslatorContext context)

Attempts to translate an arbitrary object into an instance of targetClass. If the translation couldn't be performed, null is returned.

As the translation happens while preparing configuration data, the translator receives information about the context of translation.

Parameters:

source - non-null object that is to be translated

targetClass - requested target class

context - context of the translation

Returns:

instance of targetClass; null if the translation cannot be performed; NULL_OBJECT if the result should be true null value