Editing Ant buildfiles

Because Ant buildfiles are simple text files, any text editor can be used to edit them. But there are several advantages to using the Eclipse Ant editor, including syntax coloring, content assist, navigation, occurrence marking and an outline view. To get familiar with the Eclipse Ant editor, create a simple Ant buildfile using this editor.

  1. Create an Ant buildfile called HelloWorld.xml.
  2. Open the Ant editor on the file by selecting Open With > Ant Editor from the file's context menu.
    Note: The default editor for a .xml file is a simple text editor until it has buildfile content, but this can be changed in the Window > Preferences > General > File Associations.
  3. Enter the following content in the editor:

    <?xml version="1.0" encoding="UTF-8"?>

    <project name="Hello World" default="Hello" basedir=".">

    <property name="HelloText" value="Hello"/>

    <target name="Hello">

    <echo>${HelloText}</echo>
    </target>

    </project>

    HelloWorld.xml file content

  4. Notice the syntax coloring for property values.
  5. Begin to enter a second target by typing '<tar', then hit Ctrl-Space to activate content assist. A list of valid completions is presented. Select the <target> completion and notice that the editor inserts both the opening and closing tags and leaves the cursor positioned to enter attributes for this tag.
  6. Name this target 'World'.
  7. Enter an 'echo' task for this target similar to that for the Hello target, but change the text to '${WorldText}'.
  8. Add a dependency on the 'World' target from the 'Hello' target. Place the cursor after the definition of the name attribute, hit Ctrl-Space and select the depends attribute completion. Hit Ctrl-Space again to get the completion for the other target 'World' in the buildfile.
  9. Save the buildfile contents.
  10. The full content will now be:

    <?xml version="1.0" encoding="UTF-8"?>


    <project name="Hello World" default="Hello" basedir=".">

    <property name="HelloText" value="Hello"/>
    <property name="WorldText" value="World"/>

    <target name="Hello">

    <echo>${HelloText}</echo>

    </target>

    <target name="World">

    <echo>${WorldText}</echo>

    </target>

    </project>

  11. Save the changes to HelloWorld.xml.
  12. Make the Outline view visible and notice that there are entries for each property and each target. In addition, each task under a target has an entry.
    Outline view for an Ant buildfile
  13. Clicking on an entry in the Outline view will scroll the editor to that entry. In addition, when the Outline view has focus, typing a character will move the selection in the Outline view to the next visible entry beginning with that character.
  14. Position the cursor just past the end of one of the '<target>' tags, type '<tar', then hit Ctrl-Space to activate content assist. Notice that now the only valid completions are the '</target>' and the 'tar' tag. This is because the Ant editor knows that nested targets are not allowed. Code assist in Ant editor
  15. Close the editor and do not save changes.