class EasyRdf_Literal

EasyRdf_Literal::create in drupal/core/vendor/easyrdf/easyrdf/lib/EasyRdf/Literal.php

Create a new literal object

class EasyRdf_Literal {

  /** @ignore a mapping from datatype uri to class name */
  private static $datatypeMap = array();

  /** @ignore A mapping from class name to datatype URI */
  private static $classMap = array();

  /** @ignore The string value for this literal */
  protected $value = null;

  /** @ignore The language of the literal (e.g. 'en') */
  protected $lang = null;

  /** @ignore The datatype URI of the literal */
  protected $datatype = null;

  /** Create a new literal object
   *
   * PHP values of type bool, int or float, will automatically be converted
   * to the corresponding datatype and PHP sub-class.
   *
   * If a registered datatype is given, then the registered subclass of EasyRdf_Literal
   * will instantiated.
   *
   * Note that literals are not required to have a language or datatype.
   * Literals cannot have both a language and a datatype.
   *
   * @param  mixed  $value     The value of the literal or an associative array
   * @param  string $lang      The natural language of the literal or null (e.g. 'en')
   * @param  string $datatype  The datatype of the literal or null (e.g. 'xsd:integer')
   * @return object EasyRdf_Literal (or subclass of EasyRdf_Literal)
   */
  public static function create($value, $lang = null, $datatype = null) {
    if (EasyRdf_Utils::isAssociativeArray($value)) {
      if (isset($value['xml:lang'])) {
        $lang = $value['xml:lang'];
      }
      elseif (isset($value['lang'])) {
        $lang = $value['lang'];
      }
      if (isset($value['datatype'])) {
        $datatype = $value['datatype'];
      }
      $value = isset($value['value']) ? $value['value'] : null;
    }
    if (empty($datatype)) {
      if (empty($lang)) {

        // Automatic datatype selection
        $datatype = self::getDatatypeForValue($value);
      }
    }
    elseif (is_object($datatype)) {
      $datatype = strval($datatype);
    }
    else {

      // Expand shortened URIs (qnames)
      $datatype = EasyRdf_Namespace::expand($datatype);
    }

    // Work out what class to use for this datatype
    if (isset(self::$datatypeMap[$datatype])) {
      $class = self::$datatypeMap[$datatype];
    }
    else {
      $class = 'EasyRdf_Literal';
    }
    return new $class($value, $lang, $datatype);
  }

  /** Register an RDF datatype with a PHP class name
   *
   * When parsing registered class will be used whenever the datatype
   * is seen.
   *
   * When serialising a registered class, the mapping will be used to
   * set the datatype in the RDF.
   *
   * Example:
   * EasyRdf_Literal::registerDatatype('xsd:dateTime', 'My_DateTime_Class');
   *
   * @param  string  $datatype   The RDF datatype (e.g. xsd:dateTime)
   * @param  string  $class      The PHP class name (e.g. My_DateTime_Class)
   */
  public static function setDatatypeMapping($datatype, $class) {
    if (!is_string($datatype) or $datatype == null or $datatype == '') {
      throw new InvalidArgumentException("\$datatype should be a string and cannot be null or empty");
    }
    if (!is_string($class) or $class == null or $class == '') {
      throw new InvalidArgumentException("\$class should be a string and cannot be null or empty");
    }
    $datatype = EasyRdf_Namespace::expand($datatype);
    self::$datatypeMap[$datatype] = $class;
    self::$classMap[$class] = $datatype;
  }

  /** Remove the mapping between an RDF datatype and a PHP class name
   *
   * @param  string  $datatype   The RDF datatype (e.g. xsd:dateTime)
   */
  public static function deleteDatatypeMapping($datatype) {
    if (!is_string($datatype) or $datatype == null or $datatype == '') {
      throw new InvalidArgumentException("\$datatype should be a string and cannot be null or empty");
    }
    $datatype = EasyRdf_Namespace::expand($datatype);
    if (isset(self::$datatypeMap[$datatype])) {
      $class = self::$datatypeMap[$datatype];
      unset(self::$datatypeMap[$datatype]);
      unset(self::$classMap[$class]);
    }
  }

  /** Get datatype URI for a PHP value.
   *
   * This static function is intended for internal use.
   * Given a PHP value, it will return an XSD datatype
   * URI for that value, for example:
   * http://www.w3.org/2001/XMLSchema#integer
   *
   * @return string  A URI for the datatype of $value.
   */
  public static function getDatatypeForValue($value) {
    if (is_float($value)) {
      return 'http://www.w3.org/2001/XMLSchema#decimal';
    }
    elseif (is_int($value)) {
      return 'http://www.w3.org/2001/XMLSchema#integer';
    }
    elseif (is_bool($value)) {
      return 'http://www.w3.org/2001/XMLSchema#boolean';
    }
    elseif (is_object($value) and $value instanceof DateTime) {
      return 'http://www.w3.org/2001/XMLSchema#dateTime';
    }
    else {
      return null;
    }
  }

  /** Constructor for creating a new literal
   *
   * @param  string $value     The value of the literal
   * @param  string $lang      The natural language of the literal or null (e.g. 'en')
   * @param  string $datatype  The datatype of the literal or null (e.g. 'xsd:string')
   * @return object EasyRdf_Literal
   */
  public function __construct($value, $lang = null, $datatype = null) {
    $this->value = $value;
    $this->lang = $lang ? $lang : null;
    $this->datatype = $datatype ? $datatype : null;
    if ($this->datatype) {
      if (is_object($this->datatype)) {

        // Convert objects to strings
        $this->datatype = strval($this->datatype);
      }
      else {

        // Expand shortened URIs (CURIEs)
        $this->datatype = EasyRdf_Namespace::expand($this->datatype);
      }

      // Literals can not have both a language and a datatype
      $this->lang = null;
    }
    else {

      // Set the datatype based on the subclass
      $class = get_class($this);
      if (isset(self::$classMap[$class])) {
        $this->datatype = self::$classMap[$class];
        $this->lang = null;
      }
    }

    // Cast value to string
    settype($this->value, 'string');
  }

  /** Returns the value of the literal.
   *
   * @return string  Value of this literal.
   */
  public function getValue() {
    return $this->value;
  }

  /** Returns the full datatype URI of the literal.
   *
   * @return string  Datatype URI of this literal.
   */
  public function getDatatypeUri() {
    return $this->datatype;
  }

  /** Returns the shortened datatype URI of the literal.
   *
   * @return string  Datatype of this literal (e.g. xsd:integer).
   */
  public function getDatatype() {
    if ($this->datatype) {
      return EasyRdf_Namespace::shorten($this->datatype);
    }
    else {
      return null;
    }
  }

  /** Returns the language of the literal.
   *
   * @return string  Language of this literal.
   */
  public function getLang() {
    return $this->lang;
  }

  /** Returns the properties of the literal as an associative array
   *
   * For example:
   * array('type' => 'literal', 'value' => 'string value')
   *
   * @return array  The properties of the literal
   */
  public function toArray() {
    $array = array(
      'type' => 'literal',
      'value' => $this->value,
    );
    if ($this->datatype) {
      $array['datatype'] = $this->datatype;
    }
    if ($this->lang) {
      $array['lang'] = $this->lang;
    }
    return $array;
  }

  /** Magic method to return the value of a literal as a string
   *
   * @return string The value of the literal
   */
  public function __toString() {
    return isset($this->value) ? $this->value : '';
  }

  /** Return pretty-print view of the literal
   *
   * @param  bool   $html  Set to true to format the dump using HTML
   * @param  string $color The colour of the text
   * @return string
   */
  public function dumpValue($html = true, $color = 'black') {
    return EasyRdf_Utils::dumpLiteralValue($this, $html, $color);
  }

}