function _buildFunction(resource) {
  return function(callback) {
    if (typeof callback == 'function') {
      if (resource !== null) return resource.exec.call(resource, callback);
      else return callback(null, null);
    }
    return resource;
  }
}
function _buildFunction(resource) {
  return function(callback) {
    if (typeof callback == 'function') {
      if (resource !== null) return resource.exec.call(resource, callback);
      else return callback(null, null);
    }
    return resource;
  }
}
function _buildFunction ( resource ) { return function ( callback ) { if ( typeof callback == 'function' ) { if ( resource !== null ) return resource . exec . call ( resource , callback ) ; else return callback ( null , null ) ; } return resource ; } }
Builds the function for the resource.

@param {Object|Null} resource The resource for the getter.
@return {Function}
@api private
Builds the function for the resource .