ErrorHandler
Date: 2015-12-02

org.w3c.css.sac

## Interface ErrorHandler

-     public interface ErrorHandler

  Basic interface for CSS error handlers.

  If a CSS application needs to implement customized error handling, it must implement this interface and then register an instance with the CSS parser using the parser's setErrorHandler method. The parser will then report all errors and warnings through this interface.

  The parser shall use this interface instead of throwing an exception: it is up to the application whether to throw an exception for different types of errors and warnings. Note, however, that there is no requirement that the parser continue to provide useful information after a call to fatalError (in other words, a CSS driver class could catch an exception and report a fatalError).

  The HandlerBase class provides a default implementation of this interface, ignoring warnings and recoverable errors and throwing a SAXParseException for fatal errors. An application may extend that class rather than implementing the complete interface itself.

- - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `error(CSSParseException exception)` Receive notification of a recoverable error.
    `void` | `fatalError(CSSParseException exception)` Receive notification of a non-recoverable error.
    `void` | `warning(CSSParseException exception)` Receive notification of a warning.

- - ### Method Detail

    - #### warning

          void warning(CSSParseException exception)
                       throws CSSException

      Receive notification of a warning.

      CSS parsers will use this method to report conditions that are not errors or fatal errors as defined by the XML 1.0 recommendation. The default behaviour is to take no action.

      The CSS parser must continue to provide normal parsing events after invoking this method: it should still be possible for the application to process the document through to the end.

      Parameters:
        `exception` - The warning information encapsulated in a CSS parse exception.
      Throws:
        `CSSException` - Any CSS exception, possibly wrapping another exception.
      See Also:
        `CSSParseException`

    - #### error

          void error(CSSParseException exception)
                     throws CSSException

      Receive notification of a recoverable error.

      This corresponds to the definition of "error" in section 1.2 of the W3C XML 1.0 Recommendation. For example, a validating parser would use this callback to report the violation of a validity constraint. The default behaviour is to take no action.

      The CSS parser must continue to provide normal parsing events after invoking this method: it should still be possible for the application to process the document through to the end. If the application cannot do so, then the parser should report a fatal error even if the XML 1.0 recommendation does not require it to do so.

      Parameters:
        `exception` - The error information encapsulated in a CSS parse exception.
      Throws:
        `CSSException` - Any CSS exception, possibly wrapping another exception.
      See Also:
        `CSSParseException`

    - #### fatalError

          void fatalError(CSSParseException exception)
                          throws CSSException

      Receive notification of a non-recoverable error.

      This corresponds to the definition of "fatal error" in section 1.2 of the W3C XML 1.0 Recommendation. For example, a parser would use this callback to report the violation of a well-formedness constraint.

      The application must assume that the document is unusable after the parser has invoked this method, and should continue (if at all) only for the sake of collecting addition error messages: in fact, CSS parsers are free to stop reporting any other events once this method has been invoked.

      Parameters:
        `exception` - The error information encapsulated in a CSS parse exception.
      Throws:
        `CSSException` - Any CSS exception, possibly wrapping another exception.
      See Also:
        `CSSParseException`