Using Eclipse Mylyn to Focus on a Single Issue: Hide Unrelated Resources and Preserve Context

Desired Outcome

When working on a large codebase, you often get distracted by unrelated files, breakpoints, and search results. Eclipse Mylyn lets you activate a single task, automatically filtering the Package Explorer, Outline, and search views to show only the resources that belong to that task’s context. The IDE remembers the set of open editors, breakpoints, and view layout for each task, so you can switch between work items without losing your place.

Prerequisites

• Installed Eclipse IDE (Kepler or newer). Mylyn is bundled from Eclipse 4.3 onward, but connectors may need manual installation.
• Access to a task repository (Bugzilla, JIRA, GitHub Issues, or a local task file). Repository credentials must be stored in the Preferences → Team → Task Repositories page.
• Connector plugin for the chosen repository. For example, org.eclipse.mylyn.bugzilla.core for Bugzilla or org.eclipse.mylyn.jira.core for JIRA.
• Sufficient RAM (Mylyn can increase memory usage by 50–100 MB for large repos).

Focused Procedure

1. Verify Task Repository Connectivity
   • Open Window → Show View → Task List.
   • Click the Add Repository button, choose the appropriate connector, and enter URL, username, and password.
   • After saving, the repository should appear in the Task List with a list of tasks.
2. Activate a Task
   • In the Task List, double‑click the task you want to work on, or right‑click and select Activate.
   • Mylyn will automatically filter the Package Explorer to show only the projects, packages, and files referenced by the task’s context. The Outline view will also be filtered.
   • Any open editors that are not part of the context will be closed; breakpoints outside the context are hidden.
3. Work in Context
   • Open files, edit code, and run tests as usual. All changes are recorded in the task’s context.
   • Use Search → File Search or Search → Java Search; results will be limited to the context.
4. Switch to Another Task
   • Double‑click a different task in the Task List.
   • Mylyn restores the previous task’s context: the set of open editors, breakpoints, and view layout reverts to what was saved when that task was last activated.
5. Synchronize Offline Work
   • When you have no network, continue editing. Mylyn stores changes locally.
   • Once connectivity is restored, right‑click the task and choose Synchronize to push changes to the repository.

Expected Checks

• After activating a task, the Package Explorer should display only files referenced in the task’s context. Verify by scrolling through the tree.
• Open the Breakpoints view; breakpoints outside the context should be hidden.
• Switch tasks and confirm that the previously open editors are closed and the new context’s editors are opened.
• Use Preferences → General → Workspace → Save automatically before build to ensure context changes are persisted.

Recovery Options

• If Mylyn fails to activate a task and the IDE keeps showing the previous context, reset the Task List:
  • Right‑click the repository in Task List and choose Reset.
  • Alternatively, close Eclipse and delete the .mylyn folder in your workspace (be aware this removes all contexts).
• To disable Mylyn temporarily, go to Preferences → General → Mylyn and uncheck Enable Mylyn. Restart Eclipse.
• If memory usage becomes a problem, increase the JVM heap via eclipse.ini (e.g., -Xmx2g) or reduce the number of active contexts.

Concrete Example: Activating a JIRA Issue

# 1. Add JIRA repository
# 2. Repository URL: https://jira.company.com
# 3. Username: alice
# 4. Password: (securely stored in Eclipse)
# 5. Task ID: PROJ-123

After adding the repository, double‑click PROJ-123 in the Task List. The Package Explorer now shows only the src/main/java/com/company/project package, and the Outline view lists only the classes referenced by the issue’s description. Breakpoints set in Helper.java remain active, while those in unrelated modules are hidden. Switching to PROJ-456 restores the context for that issue, closing Helper.java and opening Service.java.

Limitations & Practical Verification

• Mylyn’s filtering is based on the context metadata stored with the task. If a task’s context is empty (e.g., a new issue with no referenced files), no filtering occurs.
• Large repositories can slow down context loading. Monitor the Problems view for any Mylyn warnings.
• Verify context persistence by restarting Eclipse and re‑activating a task; the same set of editors and breakpoints should reopen.

Conclusion

Mylyn transforms Eclipse from a general IDE into a focused work environment. By activating a single task, you reduce clutter, preserve context across sessions, and keep your workflow tightly coupled to the issue at hand. Just remember to keep connectors up‑to‑date and monitor memory usage when working with large codebases.