Mastering Delphi Programming: A Complete Reference Guide

Idioms – Fluent interfaces

A concept of a builder is often used together with a concept of fluent interfaces. When an interface or a class is written in a fluent manner, its every method (or at least most of the methods) returns the implementing object itself. To put this in Delphi terms: each method returns Self.

This idiom is not specific to Delphi. Fluent interfaces are programmed in all kinds of languages, from C# to JavaScript.

Fluent interfaces allow us to chain method calls. For example, given an initialized object sb of type TStringBuilder (from unit System.SysUtils), we can create a simple string by using the following four commands:

sb.Append('The answer: ');sb.Append(42);sb.AppendLine;ShowMessage(sb.ToString);

As both Append and ...