public function __construct( $field_id, $field, $value, $additional_args = array() ) {

			// prepare object properties
			$this->result          = new stdClass;
			$this->field           = $field;
			$this->field['id']     = $field_id;
			$this->value           = $value;
			$this->additional_args = $additional_args;

			// if the field is invalid or incomplete, fail validation
			if ( ! is_array( $this->field ) || ! ( isset( $this->field['validation_type'] ) || isset( $this->field['validation_callback'] ) ) ) {
				$this->result->valid = false;
				$this->result->error = esc_html__( 'Invalid or incomplete field passed', 'tribe-common' );
				$this->result->error .= ( isset( $this->field['id'] ) ) ? ' (' . esc_html__( 'Field ID:', 'tribe-common' ) . ' ' . $this->field['id'] . ' )' : '';
			}

			// call validation callback if a validation callback function is set
			if ( isset( $this->field['validation_callback'] ) ) {
				if ( is_callable( $this->field['validation_callback'] ) || function_exists( $this->field['validation_callback'] ) ) {
					if ( ( ! isset( $_POST[ $field_id ] ) || ! $_POST[ $field_id ] || $_POST[ $field_id ] == '' ) && isset( $this->field['can_be_empty'] ) && $this->field['can_be_empty'] ) {
						$this->result->valid = true;
					} else {
						$this->result->valid = call_user_func( $this->field['validation_callback'], $value );
						if ( ! $this->result->valid ) {
							$this->result->error = esc_html__( 'Invalid or incomplete field passed', 'tribe-common' );
							$this->result->error .= ( isset( $this->field['id'] ) ) ? ' (' . esc_html__( 'Field ID:', 'tribe-common' ) . ' ' . $this->field['id'] . ' )' : '';
						}
					}
				}
			}

			if ( isset( $this->field['validation_type'] ) ) {
				if ( method_exists( $this, $this->field['validation_type'] ) ) {
					// make sure there's a field validation type set for this validation and that such method exists
					$this->type  = $this->field['validation_type'];
					$this->label = isset( $this->field['label'] ) ? $this->field['label'] : $this->field['id'];
					if ( ( ! isset( $_POST[ $field_id ] ) || ! $_POST[ $field_id ] || $_POST[ $field_id ] == '' ) && isset( $this->field['can_be_empty'] ) && $this->field['can_be_empty'] ) {
						$this->result->valid = true;
					} else {
						call_user_func( array( $this, $this->type ) ); // run the validation
					}
				} else {
					// invalid validation type set, validation fails
					$this->result->valid = false;
					$this->result->error = esc_html__( 'Non-existant field validation function passed', 'tribe-common' );
					$this->result->error .= ( isset( $this->field['id'] ) ) ? ' (' . esc_html__( 'Field ID:', 'tribe-common' ) . ' ' . $this->field['id'] . ' ' . _x( 'with function name:', 'non-existant function name passed for field validation', 'tribe-common' ) . ' ' . $this->field['validation_type'] . ' )' : '';
				}
			}
		}