Topias is an IntelliJ IDEA plugin for visualization of VCS changes frequency. When a developer opens a project in the IDE, the plugin checks if a version control system is used. If no VCS root directory is found, a warning message is shown, the plugin turns off and remains in this state until a new project is opened or a VCS root is set for the current project.

All data retrieval from a VCS history is done in the background. The full commit history for a selected time period is only browsed through once when a project is opened for the first time. After that, there is almost no impact on the overall IDE performance. When a new file from a current project is opened in the editor, the plugin queries its data model and builds visual elements for this file’s methods. This is also done in a background thread, and therefore does not affect the editor performance, but it could take an extra half a second for the visual elements to appear, which might annoy some very impatient developers.

In addition to the visual elements in the IDE’s editor, the plugin also adds a new tool window showing a list of the top 10 most frequently changed methods within this project. By default the list is placed in the bottom IDEA’s tool panel. Clicking on a method in this list allows navigating to this method’s declaration

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