|Mono: A Developer's Handbook|
|author||Edd Dumbill and Niel M. Bornstein|
|publisher||O'Reilly Media, Inc.|
|summary||An introduction to programming with Mono|
When learning a new language such as C#, or working with a new development environment such as Mono, it usually takes some time before you get up to speed in developing programs. Wading through the reference documentation and reading other people's source code often provides much-needed information on how to do certain things. Both, however, are very time consuming and tedious.
Enter Mono: A Developer's Notebook. This book provides a series of task-driven chapters which are thin on theory, but rich on practical content and example code. The featured code snippets are, in contrast to ones in books that teach theory and concepts, not solely designed to illustrate a specific theoretical aspect of programming. Each one is designed to perform a useful task that is essential in day-to-day application programming. What sets this book apart from the multitude of .NET books already available on the market? In order to answer this question it is neccesary to provide a short introduction on Mono.
Mono is essentially an open source cross-platform implementation of Microsoft's .NET development framework and implements the API's which are standardized by ECMA. It is, however, not an exact clone. Besides providing a (partially implemented) stack that provides compatibility with Microsoft's .NET API's, Mono adds a whole new API-stack of its own, consisting of open source technologies such as the Gtk+ toolkit and the Gecko HTML rendering engine. This makes it possible to develop cross-platform applications based on open source technology while (mostly) compiling from a single code-base. In contrast to most .NET books available on the market, which focus primarily on Microsoft's API's in the context of Visual Studio.NET, this book concentrates on the basic ECMA API's and Mono's own open source stack. A complete coverage of .NET and the Mono architecture is outside of this review's scope, so for more information you are advised to check the Mono Project's website.
Before we dive deeper into the content of the book, a short introduction on the Developer's Notebook series by O'Reilly may be useful. The books in this series are styled to resemble the kind of notebooks college students carry around during their classes in which to take notes or, more commonly, draw caricatures of their teachers. The 'notebook' theme persists throughout the look-and-feel of the book. The 278-page thick paperback has a glossy blue cover, complete with faux post-it note and coffee-stains. Inside, the pages are not clean white but lined like the pages found in math notebooks. In the margin, useful comments are scribbled in a font that resembles handwriting. At first I suspected that the 'busy' look would distract from the content, but in practice this was no problem, thanks to the thick black typewriter font in which the bulk of the text is printed.
The chapters in this book are referred to as labs. Each of them focuses on a specific set of tasks and/or features and is divided into several paragraphs. Most paragraphs consist of a number of standard sections following a rigid formula that help you understand a certain aspect of working with Mono. The most common sections are:
- How do I do that?: Often using a liberal amount of practical code, this section shows how to accomplish the task at hand, for example working with files.
- How it works: In this section, the code and concepts involved in the previous section are explained more in depth, step by step.
- What about...: Offers a short focus on more advanced topics or pitfalls.
- Where to learn more: If you are craving more information after reading the previous sections, you are often offered a helping hand on where to find more information, providing url's to relevant documentation such as MSDN and other websites.
The first chapter, Getting Mono Running, describes how to get Mono up and running on Linux, Windows or Mac OS X, and how to compile from source on other platforms. The installation instructions for Windows only describe how to install Mono and Gtk#. Integration of Gtk# only in an existing Visual Studio.Net installation falls outside of the scope of the book, but a recent blog entry offers some hints on how to accomplish this. Besides installation, the first chapter offers a short description of the individual tools that make up the mono development. After installation, you will want some kind of editor or IDE to work with. Both the MonoDevelop IDE and several other ways of integrating Mono into your existing environment as a Java or Windows developer are covered. Finally, the community is an important aspect of every open source project. Ways of interacting with the community as well as a guide on how to submit bugs and links to some working Mono/C# applications are part of this chapter.
The C# introduction in the second chapter, Getting Started with C#, is tailored towards people who have at least some proficiency in using an object-oriented language such as C++ or Java. Some differences between C#, Java and C++ are discussed, as well as the differences between value- and reference types, the basics of error handling, working with assemblies and more. Concepts such as classes, methods, inheritance and namespaces are assumed to be known territory. If you have no previous programming experience, Mono: A Developer's Notebook is only useful in combination with a book that teaches programming with C# such as The C# Programming Language by Anders Hejlsberg.
An important part of any modern language is its class libraries. The third chapter, Core .NET, provides an introduction to the standard Framework Library Classes, which describes essential everyday tasks that are part of every program, such as working with files, strings, searching for text patterns and handling collections of data. Besides those basic functions, the chapter also dives deeper into the internals of a compiled assembly, the handling of processes and easy multitasking using threads. Finally, the last paragraph explains how to use a .NET version of the JUnit Java Unit testing framework, Nunit, to test your code.
Developing Gtk-applications with Mono and C# is remarkably easy. Chapter 4, Gtk#, describes the basics of writing Gtk# applications. First, it's neccesary to remark that Gtk# might be a bit of a misnomer. Besides the raw Gtk+ toolkit functionality, Gtk# also includes most of the Gnome libraries like gconf, the gnome canvas, libglade and more. Chapter 4 describes functionality available in the Gtk namespace, the basic Gtk+ toolkit. Gtk+ is a constraints-based toolkit, which means that widgets are not positioned using absolute pixel coordinates but rather on basis of their logical relation to each other. This can be a bit confusing for novices, but this chapter provides a good introduction to the basic principles of writing layouts using Gtk#. The authors provide descriptions of essential operations that almost every application needs, such as creating menus and drawing pixmaps (or more advanced things like using the treeview widget and drag-and-drop), assisted by easy-to-read code snippets.
While chapter 4 introduces basic Gtk# functionality, chapter 5, Advanced Gtk#, delves deeper into more advanced features of the Gtk# library which also include functionality outside of the basic Gtk-namespace, such as the Gnome libraries. Working with Gnome button toolbars, the Glade user interface designer, storing your application settings in Gconf, setting up some preferences through the use of a wizard/druid, asynchronous operations and threading to increase responsiveness of your application while performing background tasks, rendering HTML in your application using the Gecko rendering engine and internationalisation and translation of applications are all described in this chapter.
The use of XML is tightly integrated throughout the Mono framework. It is, for example, the underlying format of the messages that web services use to communicate using the SOAP and XML-RPC protocols. The 6th chapter, Processing XML, describes the XML functionality available in Mono. It starts off by simple operations, reading and writing to an XML-file using relevant examples such as RSS and Dashboard clue-packets. It then proceeds to describe how to modify XML in memory, how to navigate and transform XML using Xpath and XSLT, how to constrain XML in several ways and how to serialize and deserialize objects into and from their XML representation. As in previous chapters, the information density is very high so it might take several reads to grok everything explained. The code examples and accompanying text however are very clear and concise.
The 7th chapter called Networking, Remoting, and Web Services describes the networking functionality available in Mono. The chapter starts off with ASP.NET. Mono's stand-alone XSP webserver and Apache integration with mod_mono are discussed, as well as the basics of writing a web application using ASP.NET's code-behind functionality which enables web applications to completely seperate presentation from the underlying code. Communication using plain tcp/ip, remoting using binary serialized objects and invoking remote procedures using XML-RPC as an alternative to SOAP are also described in this chapter. You might want to encrypt the data you send over the network, so a basic description of the Mono cryptographic API is provided. Finally, a short introduction to database handling using ADO.NET concludes chapter 7.
The 8th and last chapter titled Cutting Edge Mono starts off with an introduction on how to use the GNU Automake, Autoconf and the pkg-config tools to create an easy to build source package of your project. It then proceeds to describe various pitfalls and considerations in case you want to write cross-platform applications using Mono, such as filesystem layout, configuration storage and the calling of native code using p/invoke. A particularly cool project is IKVM, which translates Java bytecode into the Common Intermediate Language bytecode Mono uses. This enables Mono to run Java applications and allows Java and Mono code to inter-operate. A short introduction on the use of IKVM is provided, as well as some code examples on how to call Mono assemblies from Java and use the Java class libraries from within Mono applications. The chapter ends with some other cutting-edge functionality, like how to run a development version of Mono, a preview of the Generics (templates in c++) implementation available as featured in C# 2.0 and how to write Mono programs in Basic.
What is missing? The book doesn't contain a reference section on any of the described API's. If you need detailed information on the C# language specification or an API reference you will need to consult external resources such as the documentation provided with Mono, MSDN, or a separate book covering the topic to make optimal use of the information contained in this book. Fortunately, the book kindly provides pointers on where to find those. The information-density is much higher than you would expect from a book this size. This means the information contained in it is terse. Many topics are treated in a only a couple of pages and the book doesn't take time to explain a lot of programming concepts. The information gets you 'on the road' quickly however, which is exactly what this book is supposed to do.
The strength of this book is that it fills the gap between the earlier-mentioned reference documentation and the need to go out and try to read sourcecode to find out how a particular thing is done. The writing style is clear, concise and neutral. Some topics are clarified by the use of screenshots, which is especially useful in the chapters dealing with Gtk# widgets. All in all, if you are a developer with previous experience in object-oriented programming, Mono: A Developer's Notebook will provide you with an excellent introduction into many of the aspects of working with Mono, its associated libraries and programs.
More information and a sample chapter can be found at the book's homepage.
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