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Ant - The Definitive Guide
As a long time Ant user, I have written many Ant build scripts, automating my builds and speeding up the overall development cycle, mostly relying on its excellent online documentation. As a Java developer, I have admired its simple and intuitive interface and the modular design. So on getting Ant: The Definitive Guide in my hands I wasn't expecting a whole lot new to learn, and thought of using it only as a reference book.
After having the book on my desk for more than a month, though, and occasionally flipping through its pages whenever I would otherwise have consulted the online documentation, I must say that I had been missing out on some very important things: tasks like ftp and war deployment that I was simply not aware of and had never felt the need to look up, but could very well use. The other interesting thing I noticed was that my build scripts became smaller, more modular and easier to read.
Like most books in the The Definitive Guide series, Ant The Definitive Guide assumes a certain level of familiarity with underlying technologies such as Java and XML and focuses on providing complete, reference like details of Ant features and tasks. These description are generously supplemented with examples and code fragments.
But so is the the online documentation for Ant! Will someone gain additional insight in using Ant, or be able to work faster, or make better use of Ant capabilities, by consulting this book, instead of the online documentation for a particular Ant task? To find the answer, I randomly picked two topics -- filesets, an important and oft-used Ant datatype, and javac, a core Ant task -- and compared their online description with the one in the book. Here is what I found.
Besides the datatype definition, explanation of various attributes, sub-elements, and the examples, the book also covers how to specify conditional inclusion or exclusion of certain filename patterns when a property is set (or unset). Though this can be inferred from online documentation by a determined user, this particular use is far from obvious. The coverage in the book also talks about the relationship of the fileset datatype with the javac task, pointing out that the fileset attribute dir is equivalent of javac attribute srcdir, as attribute dir will be confusing in javac: is it referring to source directory or destination directory. This is the kind of insight that really helps a user.
The treatment of the javac task in the book is not much different from the one in the online documentation. Both have almost the same material, though the information in the book is better organized for new users. On the other hand, I found the online documentation to be more complete, especially with respect to the compiler specific options and behavior idiosyncrasies.
Here is a rundown on what the book covers: Chapter 1, Getting Started is a quick primer on Ant, with sufficient details for a new user to start using Ant for very simple build tasks. Chapter 2, Using Properties and Types introduces the building block tasks and datatypes, such as property, condition, fileset, path like structures, selectors and so on, used in other Ant tasks. Chapter 3, Building Java Code covers the tasks and activities around compiling Java source files (ie; javac), organizing the build steps in various targets within a single build scripts and/or across multiple scripts, generating documentation using javadoc and creating distribution jars and zip files. The rest of the chapters are devoted to tasks for specific purposes, such as launching external programs (Chapter 7, Executing External Programs), copying files and manipulating directories either on the same machine or over the network (Chapter 4, Deploying Builds), running JUnit tests (Chapter 5, Testing Builds with JUnit) and so on. There are also separate chapters covering interaction of Ant with XML and XDoclet (Chapter 9, XML and XDoclet) and with Eclipse (Chapter 11, Integrating Ant with Eclipse). The last chapter, Chapter 12, Extending Ant, talks about extending Ant by doing things like adding your own tasks, creating custom filters, writing your own build listeners and loggers etc. This chapter also has a small section on how to embed a script written in one of the supported scripting languages within an Ant script.
As you can see from this outline, the book covers almost everything that is to know about Ant and other related software.
So, what is not so good about this book? Well, I didn't find anything wrong with the topics which are actually covered by the book. Of course, there are additional things that I would have liked to see in the book: (a) A good sample Ant script which could be used as the starting point for most small to medium-sized projects; (b) A more thorough explanation of how dependencies among targets determine the execution sequence and how this fits in with explicit invocation of targets; and (c) pictures to illustrate some of the concepts such as life cycle of an Ant task, selection of files in a fileset and the dependency tree of targets.
Overall, I found the book to be comprehensive, well organized, easy to read and good value for money.
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I have worked on a couple products which have used ant as the build system. These were released a few years ago and I think the version was ant 1.3. The online doc at the time ~2002 was mediocre. I think it has gotten better now, but the book still covers all the basic features you will ever need and decreased our old make full build time from 30-40 minutes to about 10 with ant on the same hardware, as well as making it much easier to make changes and add new steps. When making minor changes ant will recompile and determine dependencies in just a few seconds where our make system would still take 5-10 minutes just for incremental change. Granted our make system could have been optimized, ant was a good excuse to start over. I have a paper copy, but do also use safari to search through the text. This gives you the best of being online and having the book.
Whoever decided to use a tab as a delimiter should not be allowed to die a natural death. This "feature" has cause countless hours of loss productivity. At one time the make processor gave some obscure warning on the missing tab and left you scratching your head for hours.
I know the moderators will hit me for this, but from the sys admins point of view - ant is evil!
/etc !!!
/etc is a very good example of what is wrong with plain text files - no single program or API could ever handle the range of formats of files there! Incidentally - XML IS plain text.
Ant isn't for sys admins.
It is simply another build program to learn. The C and C++ stuff for the kernel is "make" - now I have to learn "ant" for Java programs.
As Java isn't used (yet!) for kernel stuff, what is the problem?
I am not against learning new things, but where some people see XML as a good thing - I think it sucks! I despise any time I see a config file that is XML. XML is for the "parsing impaired" - use a plain text file like everything in
Sorry, wrong way around. XML was designed specifically from the start to be parser-friendly. There are very simple APIs which handle any XML file such as SAX.
people should use a decent editor such as emacs. its make mode highlights the tabs so you can readily see what's up.
If there isn't a GUI for editing ant files, there really should be.
Badass Resumes
Of course, most people I know who hate XML write their XML on a VERY long lines, with lots of elements jammed in together, and then they complain that it's hard to read.
Agile Artisans
1. The pulling teeth part! You need to use the 3rd party ant-contrib package to even get basic if-else and for loop functionality. And even then, since it's XML, you end up with crap like this:
.class file or somesuch. What ant needs is something like what gcc -M does for make.
<if>
<equals arg1="${foo}" arg2="bar"/>
<then>
<property name="bat" value="barf"/>
</then>
</if>
... give me a break.
What I'm always hoping for is a build system that is just a perl / python library, so I can write the build script in a real language and call the build system when I want to.
2. Ant's simplistic rebuild-on-file-mod way of doing things misses things. Say class A.java calls class B.java. You build and all is well. Then you change B.java's interface, but not where it is called in A.java. By right your build should break now, but ant only rebuilds B.java, because it's file mod time is updated; it does no analysis of what depends on it and should be rebuilt. So you run the program and if that line of code gets called you get a NoSuchMethodError, examine that stack trace, and manually delete the
... hey, I use it, but it's the year 2005 for crying out loud.
I know Make. Make is a friend of mine. Ant is no Make.
.bat or shell script...but that's sadly about where it ends.
.bat/shellscript replacement...and that's it. Claiming it is a legit replacement for Make is to completely misunderstand what Make actually is and does. That doesn't mean Ant isn't useful, it is, but it is no Make.
Ant can automate Java builds slightly better then a
The major problem is that Ant has no built in dependancy system. Dependant tasks don't count as they have no targets and thus nothing to check for dependancies. All real dependancy checking in Ant is embedded in the Ant task code...which varies task to task and worse yet has little to no documentation (not even documented to be taking place or not!). Examples are javac, zip, copy tasks.
Ant + Javamake gets closer to a Make replacement, but not completely.
But really, to be accurate Ant is a portable
My
It has been a source of constant dismay to me that something has not arisen to replace Ant in for Java builds. The Ant project has created a terrific mess where people essentially *program in XML*. XML is a set of data structure markup semantics, not a programming language. No potential of repurposing ant build files exists, another knock against using XML. Therefore, from a software architecture perspective, Ant is one of the biggest misapplications of technology I have seen to date and despite that, staggeringly popular. I rest my case and shake my head.
At this time, pretty damn solid. Yes, it's 'officially' beta, but they're just polishing the edges now.
.a full of .so files that were compiled with -fpic, and then add that whole .a into a .so. Perfectly valid, but odd, and SCon's structure didn't let us do that easily.
The only problems I've run into so far relate to SCons being a little too clever for it's own good, and not 'neatly' letting me do things that make could do. I worked around them, once I understood SCons better
For example, SCons lets you generate static and shareable objects using 'StaticObject' and 'SharedObject', and will 'do what's necessary' to make that work on your platform. Eg, under *nix, it will add '-fpic' to SharedObject. It will also refuse to let you add a StaticObject into a SharedLibrary. Which in most cases is just what you'd want to stop happening, but... if you KNOW that in a particular case it will work, then SCons is getting in the way. Eg, we wanted a
But... there's workarounds and they all 'make sense', but require a little more SCons knowledge. The mailing list is quite active and helpful, though.
If your project is straightforward (even if it's HUGE), then there's no problems at all.
Then I respectfully submit that you have very little experience JCL or Ant (or both).
Agile Artisans
[Doesnt eclipse use Ant for its builds? ]
No, it doesn't (Thank God!). You're thinking of netbeans.
Why 'thank God'? Why should internal use of Ant be a problem? On the contrary, it has major advantages: It means you can build the project outside of the IDE, and it means that the IDE can make use of just about any Java tool, as almost all of them provide functionality as Ant tasks. Compare this to eclipse, where you need to install plug-ins.