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| ===== Using the type & call hierarchy to understand code ===== | ===== Using the type & call hierarchy to understand code ===== | ||
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| + | ==== Call Hierarchy ==== | ||
| + | |||
| + | The call hierarchy shows calling relationships between methods in a program. For example: | ||
| + | |||
| + | * Navigate to the method ''toggleFolded(ListIterator listIterator)'' in class ''freemind.modes.minmapmode.actions.ToggleFoldedAction'' | ||
| + | * Right click the method name and select "Open Call Hierarchy" | ||
| + | * Look at the callers {{:hill:callers.png|}} and callees {{:hill:callees.png|}} | ||
| + | * Going back to the callers, expand ''toggleFolded'' & ''toggleFolded'' again. Look at the callers of ''actionPerformed''. | ||
| + | * Try looking at the callers of other methods, such as ''nameSetFolded'' | ||
| + | |||
| + | //**What information does the call hierarchy give you? Why is it useful for understanding a program?**// | ||
| + | |||
| + | ==== Type Hierarchy ==== | ||
| + | |||
| + | The type hierarchy shows how types are related. For example: | ||
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| + | * Right click in the editor window for ''ToggleFoldedAction'' and select "Open Type Hierarchy" | ||
| + | * Right click on ''AbstractAction'' and select "Focus On 'AbstractAction'" | ||
| + | |||
| + | //**What information does the type hierarchy give you? Why is it useful for understanding a program?**// | ||
| + | |||
| + | |||
| + | **Exercise:** Show me an interesting call hierarchy and type hierarchy on **your** project code ("interesting" = more than 3 nodes) | ||
| ===== Basic Refactoring ===== | ===== Basic Refactoring ===== | ||
| + | |||
| + | //**What is refactoring? Why use it?**// | ||
| + | |||
| + | ==Rename== | ||
| + | * Right click on ''toggleFolded'' and select "Refactor > Rename" | ||
| + | * Add your name at the end of ''toggleFolded'' | ||
| + | * Verify your change is complete by looking at the call hierarchy & double clicking the callers | ||
| + | |||
| + | //**Why rename?**// | ||
| + | |||
| + | ==Extract Method== | ||
| + | * In the renamed ''toggleFolded'', select the 3 statements (6 lines) starting with ''modeController.getAction...'' | ||
| + | * Right click & select "Refactor > Extract Method" | ||
| + | * Enter a name (e.g., "initiateToggleAction") and hit enter | ||
| + | |||
| + | //**Why extract methods?**// | ||
| ===== Debugging in Eclipse ===== | ===== Debugging in Eclipse ===== | ||
| + | //**What's debugging? What's a debugger?**// | ||
| + | |||
| + | **Task:** How does the UI toggle folding action (click, space, etc.) initiate the ''toggleFolded'' implementation? | ||
| + | |||
| + | * In the margin next to ''toggleFolded'', right click & select "Toggle Breakpoint" | ||
| + | * In the menubar, select "Window > Open Perspective > Debug" | ||
| + | * Make sure freemind isn't running | ||
| + | * Next to the green "play" arrow, select the green bug icon {{:hill:bug.png|}} - there will be some delay | ||
| + | * Toggle a node. Notice the upper-left "Debug" pane, investigate the upper-right "Variables" pane, and see the current statement in the editor pane. The arrows in the debug pane {{:hill:arrows.png|}} let you step through the execution by one method call, by one statement, or by returning. | ||
| + | |||
| + | **Exercise:** Show me a debugging trace for ''toggleFolded''. Which method calls in the trace do you think handle your input method (click, space, right click, etc.)? | ||
