1. Ant Build Tools

2.  Creating a product from source may take several steps: Compile Link Copy files to various directories Remove intermediate files Generate documentation  It becomes problematic to do all these steps manually, first of all because it’s boring, second because it is error-prone.  The objective should be an automated tool that does all the work for you. Type or click one command and create a final product.

3. Build Tools  There are a couple ways this can be done: Write a batch file or script  The scripts tend to be hard to maintain Use a tool designed for the task  Make  Ant

4. Make  Make is the original tool for this sort of thing. Roots in the Unix world  The stuff to the left of the colon is the “target”, the stuff to the right the “dependents”, and the lines below that the actions to take  If a target is newer than its dependents, the actions are performed lib.a: x.o y.o z.o ar rvu lib.a x.o y.o z.o ranlib lib.a

5. Make  Make has some well-known pathologies The action lines MUST start with a tab, which is impossible to see The action lines have platform- dependent scripting dependencies

6. Ant  The platform restrictions weren’t so bad in the Unix world, but Java was intended to be cross-platform. A build file using Make couldn’t transition from a Unix to a windows box to a Mac box. Make tends to be C- and Unix-centric.  So ant was developed as a cross- platform build tool

7. What File Format to use?  If you’re developing a new tool, what should the syntax of the file be?  The world needs fewer file formats. If you write your own unique syntax, like Make files, you wind up having to parse that syntax. That usually means a trip to yacc, lex, and friends.  Ant choose to use XML rather than develop its own syntax. This lets people leverage their existing knowledge of XML rather than learn a bunch of new rules

8. Ant  Ant is a cross-platform, XML-based system for creating software products from source code.  It is NOT a scripting language. But that doesn’t stop some people.  Open source, available at www.apache.org

9. Installing Ant  Get the binary release and set ANT_HOME and JAVA_HOME environment variables. Put the ant bin directory on the PATH environment variable.

10. Example Fragment  Creates some directories to hold the output of the build process. Matching and tags Solo tags ended with “/>” Uses XML tag attributes <target description="Preparatory actions for compilation and documentation targets" name="init">

11. Targets  A “target” is something that needs to be done—create initial directories, compile source, create javadoc, create jar files, etc.  Targets can depend on other targets The “compile” task can depend on an “init” task that creates directories for the products to land in

12. Target Dependencies  You can add a comma-delimited list of other targets that depend on this target. If the dependent target depends on other things, those will run, too. <target name=“init“ description=“Create directories”> … <target name="compile“ depends="init“ description=“Compile Java sources”> … <target name=“jar“ depends=“compile“ description=“Create jar files”> …

13. Properties  You can define variables so things like directory names aren’t hardcoded through your ant file. <property description="Source directory" location="${basedir}/source" name="dir.src"/>

14. A Simple Compile Task  Compile the source directory, put the results in the build/classes directory, and use the specified jar file <pathelement location=“${lib.dir}/somelib.jar”

15. Ant Files  Often you need to specify lists of files (as in classpaths). It is brittle to do this by using a long quoted series of files Path=“foo.jar,baz.jar,xml.jar,…”  Ant can handle this by using lists of XML tags  can have multiple tags embedded.  This is somewhat more maintainable than a single quoted list.

16. Filesets  Often you want to specify a whole series of files, as with the classpath example, when many jar files needed to be specified  Rather than individually name every jar file, you can specify a set of files, in this case in the lib directory and all subdirectories of the lib directory. You can also use regexps to select files in the fileset.

17. Popular Ant Tasks  Javac  Javadoc  jar  Mkdir  Copy  Delete  Junit (automated tests)  FTP (FTP a result to a server)

18. User-Written tasks  You can also write your own tasks with fairly low quantities of drama  This has been used to do things like automatically deploy servlets to a tomcat server as part of the build process

19. Ant files  Ant files are usually named “build.xml” and usually reside in the root of your project directory.  To run, type “ant ”.

20. Simple Example  Write an ant file for a simple project  Source directory, compile to a build directory, do jar and javadoc  Tasks for init, compile, jar, javadoc, clean Foo build.xml source a.java b.java build classes doc project.jar

21. Simple Example  See http://www.movesinstitute.org/~mcg redo/ant/example.tar.gz for the example with a simple project http://www.movesinstitute.org/~mcg redo/ant/example.tar.gz

22. Parting thoughts  Don’t depend on manual build steps if at all possible  The objective should be typing or clicking “ant” which leads to a functioning product from source  It’s possible, but probably a bad idea, to use ant for C++/C