1 Ant – Another Neat Tool Representation and Management of Data on the Internet

2 What is Ant? A cross-platform build tool (like make) A scripting framework Based on industry standards (Java and XML) Open Source (development coordinated by the Apache Jakarta project)

3 Make versus Ant Make: OS dependent – uses shell commands Ant: OS independent – uses Java Make: Terrible syntax (infamous tabbing problem) Ant: XML based syntax Make: state dependencies between program files Ant: state dependencies between tasks (not between program files)

4 Why Ant? Platform independent –Requires only a JDK 1.1 or later JVM Easy to use –Built-in tasks accomplish all typical build functions –User contributed tasks cover most other needs Easy to extend –Create a new task by writing some Java code

5 What can we do with Ant? Can be used to: –compile java programs –create javadoc documentation –create jar, zip, tar, war files –delete and copy files –send mail –validate XML files –etc. (anything you want)

6 Structure of Ant Project –a top level collection of targets Property –an Ant variable Target –a collection of tasks executed to achieve a particular purpose (a goal) Task –a unit of Ant execution (a step)

7 How Does Ant Work? Each Project will have a build file (build.xml) Each build file will contain one or more Targets The Target to be executed: –Is either explicitly selected on the command line –Or a project default Target is executed Each Target is executed only once Each Target will contain one or more Tasks Some Tasks are executed conditionally Tasks are implemented as Java classes

8 Using Ant Buildfiles are written in XML Each buildfile contains a single project Projects can have 3 attributes: –name: name of project (optional) –default: default target to use (required) –basedir: base directory for paths (optional)

9 A BuildFile – Project Element XML Element Comment

10 Properties Properties (similar to global values) are defined as follows: Note: Properties are XML elements without contents, therefore we use /> A property “propName” can be referred to later using the syntax ${propName} You can define any properties you want

11 A BuildFile – Adding Properties

12 Targets Targets have the attributes: –name: name of the target (required) –depends: comma separated list of targets on which the target depends (optional) –if, unless, description: details omitted (read about it in the Ant documentation) Targets contain tasks as subelements. These tasks define the actions performed when the target is executed.

13 A BuildFile – Adding a Target We call also have written: A Task

14 A More Complex Example Note: The tstamp task ( ) defines the properties: DSTAMP (with format “yyyymmdd”), TSTAMP (with format “hhmm”) and TODAY (with format “month day year”)

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16 <!-- Put everything in ${build} into the jar file: MyProject-${DSTAMP}.jar file --> <jar jarfile="${dist}/lib/MyProject-${DSTAMP}.jar" basedir="${build}"/>

17 More about Depends Ant tries to execute the targets in “depends” from left to right. However, a target may be executed early when another one depends on it.

18 Example 1 Execute: ant D In what order will the tasks be performed? Try DTry CTry BTry A Do DDo CDo BDo A Note: B is executed before C! Note: B is executed once!

19 Example 2 Execute: ant A In what order will the tasks be performed? The build fails, ant reacts with: –“Circular dependancy: a <- b <- a”

20 Running Ant Type: ant Ant looks for the file: build.xml, and performs the default task specified there. You can use the –buildfile option to specify a different buildfile You can specify a different task to be performed You can define parameters using the –D option

21 Examples Run Ant using build.xml on the default target ant Run Ant using the test.xml file on the default target ant -buildfile test.xml Run Ant using the test.xml file on a target called dist: ant -buildfile test.xml dist

22 Examples (cont.) Run Ant using the test.xml file on a target called dist, setting the build property to the value build/classes: ant -buildfile test.xml -Dbuild=build/classes dist

23 References To learn more about Ant: –Look at the documentation on the web. (reference from the table of lectures schedule) –Pay attention to the section: “Built-in Tasks”. For each task, the format (e.g., name and attributes) appears.