DAIA::Message - An optional information text or error message

Messages can occurr as property of DAIA::Response, DAIA::Document, DAIA::Item, and DAIA::Availability objects.

content

The message as plain Unicode string. The default value is the empty string.

lang

A mandatory RFC 3066 language code. The default value is defined in $DAIA::Message::DEFAULT_LANG and set to 'en'.

errno

An integer value error code. By default a message has no error code.

The message function is a shortcut for the DAIA::Message constructor:

  $msg = DAIA::Message->new( ... );
  $msg = message( ... );

The constructor understands several abbreviated ways to define a message:

  $msg = message( $content [, lang => $lang ] [, errno => $errno ] )
  $msg = message( $lang => $content [, errno => $errno ] )
  $msg = message( $lang => $content [, $errno ] )

The value undef as error code is ignored on construction. You can undefine an error code by explicitely setting it to undef.

  $msg->errno( undef );

To set or get all messages of an object, you use the messages accessor. You can pass an array reference or an array:

  $messages = $document->message;  # returns an array reference

  $document->message( [ $msg1, $msg2 ] );
  $document->message( [ $msg ] );
  $document->message( $msg1, $msg2);
  $document->message( $msg );

To append a message you can use the add or the addMessage method:

  $document->add( $msg );         # $msg must be a DAIA::Message
  $document->addMessage( ... );   # ... is passed to message constructor

  $document += $msg;              # same as $document->add( $msg );

In addition to the message function there is the error function to quickly construct error messages. The first parameter is always treated as error number:

  error() # errno = 0
  error( $errno [, $lang => $content ] ) 
  error( $errno, $content [, lang => $lang ] )

Returns whether $tag is a formally valid language tag. The regular expression follows XML Schema type xs:language instead of RFC 3066. For true RFC 3066 support have a look at I18N::LangTags.

Jakob Voss <jakob.voss@gbv.de>

Copyright (C) 2009-2010 by Verbundzentrale Goettingen (VZG) and Jakob Voss

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.8 or, at your option, any later version of Perl 5 you may have available.