IntelliJ IDEA 2023.3 Help

UML class diagrams

Enable the Diagrams plugin

This functionality relies on the Diagrams plugin, which is bundled and enabled in IntelliJ IDEA by default. If the relevant features aren't available, make sure that you didn't disable the plugin.

  1. Press Ctrl+Alt+S to open the IDE settings and then select Plugins.

  2. Open the Installed tab, find the Diagrams plugin, and select the checkbox next to the plugin name.

IntelliJ IDEA lets you generate a diagram on a package in your project. Such diagrams always reflect the structure of actual classes and methods in your application.

View diagram on a package

  1. In the Project tool window, right-click a package for which you want to create a diagram and select Diagrams | Show Diagram Ctrl+Alt+Shift+U).

  2. In the list that opens, select Java Class Diagram. IntelliJ IDEA generates a UML diagram for classes and their dependencies.

Analyze class diagram

To see the list of methods, fields, and other code elements, select the appropriate icon on the diagram toolbar located on top of the diagram editor.

Diagram editor

The lists are displayed based on the selected visibility level, which you can change. For example, to view protected methods, click the Change Visibility Level button on the diagram toolbar and select protected from the list. IntelliJ IDEA displays members with visibility not less than protected, such as public, package local, and protected ones. The protected methods are displayed with modifier icons key next to them.

Visibility level

You can click the the Show Dependencies icon icon to see class dependencies. IntelliJ IDEA follows the UML conventions in showing relationships between the classes.

class_dependencies.png

When you click through classes in the graph, IntelliJ IDEA greys out classes that do not reside in the same package. This might be helpful, when you generate a diagram on a package that contains inner packages.

different_packages.png

To save the diagram as a file, right-click the diagram editor and from the context menu, select Export Diagram | Export to File and then the file extension in which you want to save the diagram.

Manage class diagram

When working with diagrams, use the context menu in the diagram editor to perform different tasks. You can view members of the class, add new, delete the existing ones, see implementations, check parent classes, perform basic refactoring, add notes, and so on.

View the diagram structure

  1. Generate a diagram.

  2. Click Structure in the left toolbar. IntelliJ IDEA opens the Structure tool window that displays a map of your diagram with a small preview of the selected block and its neighbors.

    the Structure view

    Use the context menu to zoom in and out, move canvas, change layout, and export part of the diagram into an image.

    the context menu

Add an existing class to a diagram

  1. Press Space.

  2. In the search field that opens, start typing a name of the class you want to add. Then, select the desired class from the suggestion list.

    If you want to add a class that is out of the project scope, select the Include non-project items checkbox.

    Alternatively, select one or more elements in the Project tool window and drag them to the diagram.

Delete a node element from the diagram

  1. In the diagram editor, select a node element you want to delete.

  2. Right-click the element and from the context menu, select Delete Delete.

    Alternatively, select Refactor | Safe Delete Alt+Delete. In this case, IntelliJ IDEA checks for usages before applying the changes.

Add new members to a class

You can perform some forward engineering while in the diagram editor.

  1. In the diagram editor, right-click anywhere and from the context menu, select Content | New. Then select a code element you want to create.

  2. Depending on your selection, IntelliJ IDEA opens the appropriate dialog where you specify the necessary information for creating the new element.

IntelliJ IDEA adds the item to your diagram as well as to your project tree .

View implementations and parent classes

You can view implementations and parent classes in your diagram. If IntelliJ IDEA finds more than one parent class or implementation, it displays a list of appropriate items. Select the one you need to see the connections between the parent and its children.

  1. In the diagram editor, select an item for which you want to see implementations or parent classes.

  2. Right-click the items and from the context menu, select the Show Implementations Ctrl+Alt+B or Show Parents Ctrl+Alt+P respectively.

  3. In the popup that opens, select items you need and press Enter. To extend your selection up or down while in the popup, press Shift+Up or Shift+Down respectively.

Configure diagram settings

You can configure the diagram settings so that you have certain options available by default when you create a diagram.

  1. Press Ctrl+Alt+S to open the IDE settings and then select Tools | Diagrams.

  2. In the right-hand pane, select the options that you want to see by default and click OK to apply your changes.

Analyze graph

The Analyze Graph action group lets you analyze the graph in various ways such as perform auto clusterization, measure the node centrality, search cycles, filter path between two nodes, and so on.

Filter paths between two nodes

Most of the time, generated diagrams are big and complicated. Typically, you want to concentrate only on the specific part of the diagram. IntelliJ IDEA lets you filter paths between two diagram elements.

  1. In the diagram editor, select two nodes on which you want to focus and right-click one of them to open the context menu.

  2. From the context menu, select Analyze Graph | Focus On Paths Between Two Nodes.

  3. In the dialog that opens, select additional options if needed and click Find.

    the Focus on Paths between Two Nodes dialog

    IntelliJ IDEA displays connections associated only with the selected nodes.

    Paths between nodes

Measure diagram centrality

You can use this action to identify the important nodes in the graph.

  1. In the diagram editor, right-click anywhere in the editor to open the context menu.

  2. From the context menu, select Analyze Graph | Measure Centrality.

  3. In the dialog that opens, select additional options if needed and click Measure.

    Measure Centrality

    The node "importance" is expressed via fractional value from 0.0 to 1.0 measurement, and the brightest node selection should be explored first.

    Measure Nodes
Last modified: 15 March 2024