org.eclipse.rdf4j.rio

Interface LanguageHandler

All Known Implementing Classes:

BCP47LanguageHandler, RFC3066LanguageHandler

public interface LanguageHandler

An interface defining methods related to verification and normalization of language tags.

The language handler may optionally provide normalization and verification services for string literals based on the language tags, including translation, grammar and spelling checks. However, this behavior is entirely driven by the user.

Author:

Peter Ansell

Field Summary

Fields

Modifier and Type	Field and Description
static String	BCP47 Identifier for the language tag format defined by BCP47, which is referenced by the RDF-1.1 specification.
static String	RFC3066 Identifier for the language tag format defined by RFC3066, which is referenced by the RDF-1.0 specification.
static String	RFC4646 Identifier for the language tag format defined by RFC4646, which obsoletes RFC3066, but which is not referenced by the RDF specification.

Method Summary

Modifier and Type	Method and Description
String	getKey() A unique key for this language handler to identify it in the LanguageHandlerRegistry.
boolean	isRecognizedLanguage(String languageTag) Checks if the given language tag is recognized by this language handler, including cases where the language tag is recognized, but is not yet normalized.
Literal	normalizeLanguage(String literalValue, String languageTag, ValueFactory valueFactory) Normalize both the language tag and the language if appropriate, and use the given value factory to generate a literal matching the literal value and language tag.
boolean	verifyLanguage(String literalValue, String languageTag) Verifies that the language tag is valid, optionally including an automated check on the literal value.

Field Detail

RFC3066

static final String RFC3066

Identifier for the language tag format defined by RFC3066, which is referenced by the RDF-1.0 specification.

See Also:

Constant Field Values

RFC4646

static final String RFC4646

Identifier for the language tag format defined by RFC4646, which obsoletes RFC3066, but which is not referenced by the RDF specification.

See Also:

Constant Field Values

BCP47

static final String BCP47

Identifier for the language tag format defined by BCP47, which is referenced by the RDF-1.1 specification.

See Also:

Constant Field Values

Method Detail

isRecognizedLanguage

boolean isRecognizedLanguage(String languageTag)

Checks if the given language tag is recognized by this language handler, including cases where the language tag is recognized, but is not yet normalized.

Parameters:

languageTag - The language tag to check.

Returns:

True if the language tag is syntactically valid and could be used with verifyLanguage(String, String) and normalizeLanguage(String, String, ValueFactory).

verifyLanguage

boolean verifyLanguage(String literalValue,
                       String languageTag)
                throws LiteralUtilException

Verifies that the language tag is valid, optionally including an automated check on the literal value.

This method must only be called after verifying that isRecognizedLanguage(String) returns true for the given language tag.

Parameters:

literalValue - Literal value matching the given language tag.

languageTag - A language tag that matched with isRecognizedLanguage(String).

Returns:

True if the language tag is recognized by this language handler, and it is verified to be syntactically valid.

Throws:

LiteralUtilException - If the language tag was not recognized.

normalizeLanguage

Literal normalizeLanguage(String literalValue,
                          String languageTag,
                          ValueFactory valueFactory)
                   throws LiteralUtilException

Normalize both the language tag and the language if appropriate, and use the given value factory to generate a literal matching the literal value and language tag.

This method must only be called after verifying that isRecognizedLanguage(String) returns true for the given language tag, and verifyLanguage(String, String) also returns true for the given language and literal value.

Parameters:

literalValue - Required literal value to use in the normalization process and to provide the value for the resulting literal.

languageTag - The language tag which is to be normalized. This tag is available in normalized form from the result using Literal.getLanguage().

valueFactory - The ValueFactory to use to create the result literal.

Returns:

A Literal containing the normalized literal value and language tag.

Throws:

LiteralUtilException - If the language tag was not recognized or verified, or the literal value could not be normalized due to an error.

getKey

String getKey()

A unique key for this language handler to identify it in the LanguageHandlerRegistry.

Returns:

A unique string key.