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Visual DbC

Visual DbC is a proof management and visualization tool. It allows to visualize code members (e.g. types, attributes, methods) together with specifications (e.g. method contracts, invariants) and proofs in a DbC diagram similar to an UML class diagram. Proof references are used to indicate that a code member or a specification is used by a proof.

The following sections illustrate the main features of Visual DbC using screenshots. Each section contains numbered screenshots that explain a usage scenario step by step. Clicking on each picture produces a more detailed view. The screenshots may differ from the latest release.


Visual DbC is compatible with Eclipse Indigo (3.7) or newer.

Required update-sites and installation instructions are available in the download area.

Visualize existing source code

  1. Select package to visualize its source code. Subpackages will be automatically included.

  2. Open new wizard via context menu item "New, Other..." of the selected package.

  3. Select "Visual DbC, DbC Diagram from Data Source".

  4. Define the file name of the diagram file. This file contains the graphical representations.

  5. Define the file name of the model file. This file contains the content.

  6. Optionally change the package treatment and finish the wizard.

  7. Inspect the generated diagram. The layout of selected diagram elements can be improved by selecting main menu item "Diagram, Arrange, All".

Do proofs with a DbC diagram

  1. Add a proof and name it "ContractPO".

  2. Add a proof target reference from the proof to the element to verify.

  3. Select "Open Proof" in the context menu of the proof.

  4. Do the proof as normal in the user interface of KeY.

  5. Detected proof references are automatically added to the diagram.

  6. View "Statistic" shows the status of all proof obligations.

Visualize proof dependencies of a proof in the KeYIDE

  1. Do the proof in the KeYIDE as normal.

  2. Open view "Proof Dependencies" via main menu item "Window, Show View, Proof Dependencies".

  3. Inspect the used code members and specifications in view "Proof Dependencies".

KeY basics in Eclipse and troubleshooting