Jexa: Java Examiner

prerelease version of 1999.10.11
Copyright (c) 1997, 1998, 1999 Massachusetts Institute of Technology.
This software is provided "as is" without express or implied warranty.

Jexa extends Outliner with specific renderers for:

• JavaBeans (property introspection),
• Classes (static field reflection),
• Collections (elements),
• Lists (indexed elements),
• Maps (keyed values),
• Containers (AWT component hierarchy),
• TreeNodes (JTree node hierarchy), and
• Objects (local instance field reflection).

For example, when an AWT Frame object is rendered with ContainerRenderer, its outline children are its parent and components in the AWT component containment hierarchy.

An object may have several alternate renderers. For example, an AWT Frame may be renderered by ContainerRenderer, BeanRenderer, and ObjectRenderer. The pop-up menu in the image shows the current renderer is ContainerRenderer; the renderer sub-menu shows that in addition to the three renderers just mentioned, a custom renderer called ContainerChildRenderer can render a Frame.

BeanRenderer displays the JavaBean properties of the object as returned by java.beans.Introspector. These are determined by the BeanInfo for the object, or by reflecting to find its public get---() is---(), and get---(int) methods.

ObjectRenderer uses reflection to display the fields of the object. This is often not as informative as BeanRenderer, especially when the object is a wrapper, e.g., a remote object stub or a synchronizing wrapper. When running under a security manager as in an applet, ReflectionPermission is rejected so non-public fields cannot be displayed.

See Jexa javadoc for more details and examples of custom extensions.

Download a jar from the Jars page.

Jexa Release Notes

1999-06-09: JFC/Swing: Jexa has been reimplemented around the new Outliner architecture, which builds on JFC/Swing JTree; see Outliner for details. One improvement is there may now be more than one renderer per class or interface in an OutlineMaker renderer table. Renderers: added a TreeNodeRenderer for debugging JTrees and Outlines. Improved BeanRenderer's handling of indexed properties, and properties of non-public classes. Popup menu: Added popup menu command to highlight multiple appearances of the moused object. Added debugging option to examine the current outline node itself (Jexa.dbgLev). Localization: Jexa may be localized; for international use, menu strings are properties that may be overridden according to language of default locale. (AWT Version: For users who have built outline generators based on the old architecture, the old AWT Jexa has been updated to use the monospaced font, and moved to edu.mit.ai.psg.jexa.awt. The AWT version will be phased out in the future.)

1999-02-28 version: Jexa renderers for new Collection, List, Map utilities; BeanRenderer restricted to true Java bean properties; ObjectRenderer can be used to show non-public fields.

Known problem: Under Sun's Java1.2 or Java1.2.1, re-rendering a Class with BeanRenderer encounters a fatal bug in the native libraries for Class, halting the Java virtual machine. It works correctly in Java1.2.2rc1 (release candidate 1 is an early access release available through Java Developer Connection). Workaround: If you can't use Java1.2.2rc1 or later, don't re-render classes with BeanRenderer. (ClassRenderer is the default renderer for classes, and it doesn't run into this problem.)