Saving & Reusing Ant options
When we ran the HelloWorld.xml Ant buildfile in the last section,
the choice of targets, along with all other options in the Run Ant dialog were
saved in an entity called a 'launch configuration'. Launch configurations contain
all details necessary to run a single Ant buildfile in a particular way. It is
perfectly valid to have multiple launch configurations associated with a single
Ant buildfile. So, in addition to the launch configuration that was created in
the last step, specifying that our HelloWorld.xml buildfile should execute the
targets Hello & World in that order, we could create a second launch configuration
for this same buildfile specifying the same targets but in the reverse order. So
far so good. But the really nice thing about launch configurations is that now
you can quickly run your Ant buildfile in either configuration by simply specifying
the corresponding launch configuration.
- From the External Tools drop down on the Workbench toolbar, select External
Tools....
- The External Tools dialog opens. This should look a lot like the Run Ant
dialog we saw previously. In fact, it's identical except that in the External
Tools dialog, you have a choice of which launch configuration you wish to
view and edit. The launch configuration we created when we ran the build.xml
buildfile is selected in the tree at the left, and the tabs on the right show
the options for this launch configuration.
- At the top of the dialog, change the Name to 'Hello World' and Apply the
change.
- In the tree at left, bring up on the context menu on the selected launch
configuration and choose Duplicate. A copy of the launch configuration for
the Hello World buildfile is created, '(1)' is appended to the name, and the
new launch configuration is selected in the tree.
- Rename the new configuration to 'World Hello'.
- In the Targets tab, click the Order... button, change the order of the
targets so that the World target executes first, and Apply the change.
- Click Run.
- As before, the HelloWorld.xml buildfile runs and sends its output to the Console
view. This time however, because the targets were reversed, the output is
reversed as well.
- Go back to the External Tools drop down in the toolbar.

Notice now that there are two entries in the history, one for Hello World
and one for World Hello. In order to rerun the Ant buildfile so that it outputs
Hello World, just select this launch configuration in the history. To rerun
the launch configuration that outputs World Hello, select this configuration
in the history. Note that the history is ordered so that the most frequently
run configurations are at the top of the dropdown.
This concludes our quick look at the basics of Ant integration in Eclipse.
In the next chapters, we consider several real-world use cases for running Ant
buildfiles inside Eclipse.