function Interface() {}

/**
 * Implements an interface.
 * @param {Object} implementation The interface implementation.
 * @param {Array<Object>} interfaces The implemented interfaces.
 */
Interface.implements = function(implementation, interfaces) {
  interfaces = Array.prototype.slice.call(arguments, 1);
  window.addEventListener('load', function() {
    for (var i = 0, interface; interface = interfaces[i]; i++) {
      var properties = Object.keys(interface.prototype);

      for (var j = 0, property; property = properties[j]; j++) {
        var interfaceProperty = interface.prototype[property];
        var implementationProperty = implementation.prototype[property];

        if (typeof interfaceProperty === 'function' &&
            (typeof implementationProperty !== 'function' ||
            implementationProperty.length !== interfaceProperty.length)) {
          throw new Error('Abstract method ' + property + ' is not overriden');
        } else {
          implementation.prototype[property] = interfaceProperty;
        }
      }
    }
  });
};