class EasyRdf_Literal_Boolean

Boolean.php in drupal/core/vendor/easyrdf/easyrdf/lib/EasyRdf/Literal/Boolean.php

class EasyRdf_Literal_Boolean extends EasyRdf_Literal {

  /** Constructor for creating a new boolean literal
   *
   * If the value is not a string, then it will be converted to 'true' or 'false'.
   *
   * @param  mixed  $value     The value of the literal
   * @param  string $lang      Should be null (literals with a datatype can't have a language)
   * @param  string $datatype  Optional datatype (default 'xsd:boolean')
   * @return object EasyRdf_Literal_Boolean
   */
  public function __construct($value, $lang = null, $datatype = null) {
    if (!is_string($value)) {
      $value = $value ? 'true' : 'false';
    }
    parent::__construct($value, null, $datatype);
  }

  /** Return the value of the literal cast to a PHP bool
   *
   * If the value is 'true' or '1' return true, otherwise returns false.
   *
   * @return bool
   */
  public function getValue() {
    return strtolower($this->value) === 'true' or $this->value === '1';
  }

  /** Return true if the value of the literal is 'true' or '1'
   *
   * @return bool
   */
  public function isTrue() {
    return strtolower($this->value) === 'true' or $this->value === '1';
  }

  /** Return true if the value of the literal is 'false' or '0'
   *
   * @return bool
   */
  public function isFalse() {
    return strtolower($this->value) === 'false' or $this->value === '0';
  }

}