Viewing the type hierarchy
In this section, you will learn about using the Hierarchy view by viewing
classes and members in a variety of different ways.
- In the Package Explorer view, find junit.framework.TestCase.java.
From its context menu, select Open Type Hierarchy. You
can also open type hierarchy view:
- from the menu bar by selecting Navigate > Open Type
Hierarchy.
- from the keyboard by pressing F4 after selecting TestCase.java.
- The buttons in the view tool bar control which part of the hierarchy is
shown. Click the Show the Type Hierarchy button
to see the class hierarchy, including the base classes and subclasses. The
small arrow on the left side of the type icon of TestCase indicates that the
hierarchy was opened on this type.
- Click the Show the Supertype Hierarchy button to
see a hierarchy showing the type's parent elements including implemented
interfaces. This view shows the results of going up the type hierarchy.
In this "reversed hierarchy" view, you can see that TestCase implements
the Test interface.
- Click the Show the Subtype Hierarchy button in the
view toolbar.
- Click the Lock View and Show Members in Hierarchy
button in the toolbar of the member pane, then select the runTest() method
in the member pane. The view will now show all the types implementing runTest().
- In the Hierarchy view, click the Show the Supertype Hierarchy
button. Then on the member pane, select
countTestCases()
to display
the places where this method is declared.
- In the Hierarchy view select the Test element and select Focus
On 'Test' from its context menu. Test is presented in the Hierarchy view.
- Activate the Package Explorer view and select the package junit.framework.
Use Open Type Hierarchy from its context menu. A hierarchy
is opened containing all classes of the package. For completion of the tree,
the hierarchy also shows some classes from other packages. These types are
shown by a type icon with a white fill.
- Use Previous Type Hierarchies to go back to a previously
opened element. Click on the arrow next to the button to see a list of elements or click
on the button to edit the history list.
- From the menu bar, select Window > Preferences.
Go to Java and select Open a new Type Hierarchy
Perspective. Then click OK.
- In the Hierarchy view, select the Test element again, and activate Open
Type Hierarchy from the Navigate menu bar. The resource containing
the selected type is shown in a new perspective (the Hierarchy perspective),
and its source is shown in the Java editor. By setting the preference
option for viewing type hierarchy perspectives, you can have more than one
type hierarchy in your workbench and switch between them as needed.
Close the Hierarchy perspective before proceeding to the next step.
Java views
Using the Hierarchy view
Type Hierarchy view
Java Base preference page