Code Hierarchy

Code hierarchy views allow developers to explore structural relationships in their code. Consulo supports three hierarchy views: Type Hierarchy (supertypes and subtypes of a class), Method Hierarchy (overriding and implementing methods across a class hierarchy), and Call Hierarchy (callers and callees of a method). Each view is provided by implementing a dedicated provider interface.

HierarchyProvider

HierarchyProvider is the base interface for all hierarchy providers. It implements LanguageExtension and defines three methods that every hierarchy provider must implement:

Method	Description
getTarget(DataContext dataContext)	Returns the PSI element for which the hierarchy should be displayed, based on the current action context. Returns null if the action is not applicable.
createHierarchyBrowser(PsiElement target)	Creates a HierarchyBrowser instance for viewing the hierarchy of the specified element.
browserActivated(HierarchyBrowser hierarchyBrowser)	Called when the hierarchy tool window is shown and the given browser is currently displayed.

HierarchyBrowser

HierarchyBrowser represents the UI component displayed in the Hierarchy tool window. It defines:

Method	Description
getComponent()	Returns the JComponent to be displayed in the tool window.
setContent(Content content)	Notifies the browser that it is being displayed in the specified Content tab.

TypeHierarchyProvider

TypeHierarchyProvider is annotated with @ExtensionAPI(ComponentScope.APPLICATION) and extends HierarchyProvider. It provides the Type Hierarchy view, which shows supertypes and subtypes of a selected class or type.

Registration

import consulo.annotation.component.ExtensionImpl;
import consulo.dataContext.DataContext;
import consulo.language.Language;
import consulo.language.editor.hierarchy.HierarchyBrowser;
import consulo.language.editor.hierarchy.TypeHierarchyProvider;
import consulo.language.psi.PsiElement;
import jakarta.annotation.Nonnull;
import jakarta.annotation.Nullable;

@ExtensionImpl
public class MyTypeHierarchyProvider implements TypeHierarchyProvider {

    @Nonnull
    @Override
    public Language getLanguage() {
        return MyLanguage.INSTANCE;
    }

    @Nullable
    @Override
    public PsiElement getTarget(@Nonnull DataContext dataContext) {
        // Extract the class element from the data context
        // Return null if the caret is not on a class declaration
        return findTargetClass(dataContext);
    }

    @Nonnull
    @Override
    public HierarchyBrowser createHierarchyBrowser(PsiElement target) {
        // Create and return a browser component showing the type hierarchy
        return new MyTypeHierarchyBrowser(target);
    }

    @Override
    public void browserActivated(@Nonnull HierarchyBrowser hierarchyBrowser) {
        // Perform any setup needed when the browser is displayed
    }

    // ... helper methods omitted for brevity
}

MethodHierarchyProvider

MethodHierarchyProvider is annotated with @ExtensionAPI(ComponentScope.APPLICATION) and extends HierarchyProvider. It provides the Method Hierarchy view, which shows how a method is overridden or implemented across the type hierarchy.

Registration

import consulo.annotation.component.ExtensionImpl;
import consulo.dataContext.DataContext;
import consulo.language.Language;
import consulo.language.editor.hierarchy.HierarchyBrowser;
import consulo.language.editor.hierarchy.MethodHierarchyProvider;
import consulo.language.psi.PsiElement;
import jakarta.annotation.Nonnull;
import jakarta.annotation.Nullable;

@ExtensionImpl
public class MyMethodHierarchyProvider implements MethodHierarchyProvider {

    @Nonnull
    @Override
    public Language getLanguage() {
        return MyLanguage.INSTANCE;
    }

    @Nullable
    @Override
    public PsiElement getTarget(@Nonnull DataContext dataContext) {
        // Extract the method element from the data context
        return findTargetMethod(dataContext);
    }

    @Nonnull
    @Override
    public HierarchyBrowser createHierarchyBrowser(PsiElement target) {
        return new MyMethodHierarchyBrowser(target);
    }

    @Override
    public void browserActivated(@Nonnull HierarchyBrowser hierarchyBrowser) {
        // Perform any setup needed when the browser is displayed
    }
}

CallHierarchyProvider

CallHierarchyProvider is annotated with @ExtensionAPI(ComponentScope.APPLICATION) and extends HierarchyProvider. It provides the Call Hierarchy view, which shows the callers (and optionally callees) of a selected method.

Registration

import consulo.annotation.component.ExtensionImpl;
import consulo.dataContext.DataContext;
import consulo.language.Language;
import consulo.language.editor.hierarchy.CallHierarchyProvider;
import consulo.language.editor.hierarchy.HierarchyBrowser;
import consulo.language.psi.PsiElement;
import jakarta.annotation.Nonnull;
import jakarta.annotation.Nullable;

@ExtensionImpl
public class MyCallHierarchyProvider implements CallHierarchyProvider {

    @Nonnull
    @Override
    public Language getLanguage() {
        return MyLanguage.INSTANCE;
    }

    @Nullable
    @Override
    public PsiElement getTarget(@Nonnull DataContext dataContext) {
        // Extract the method/function element from the data context
        return findTargetCallable(dataContext);
    }

    @Nonnull
    @Override
    public HierarchyBrowser createHierarchyBrowser(PsiElement target) {
        return new MyCallHierarchyBrowser(target);
    }

    @Override
    public void browserActivated(@Nonnull HierarchyBrowser hierarchyBrowser) {
        // Perform any setup needed when the browser is displayed
    }
}

Implementation Notes

All three hierarchy provider interfaces -- TypeHierarchyProvider, MethodHierarchyProvider, and CallHierarchyProvider -- inherit the same three methods from HierarchyProvider. The only difference is the semantic contract: each interface is registered as its own extension point so the platform knows which provider to invoke for which hierarchy action.

The typical implementation pattern is:

1. In getTarget(), use the DataContext to locate the relevant PSI element (class, method, or callable) at the current caret position. Return null if the context is not applicable.
2. In createHierarchyBrowser(), construct a HierarchyBrowser that builds and displays the tree structure for the target element.
3. In browserActivated(), perform any additional initialization after the hierarchy tool window becomes visible (for example, selecting the initial view or expanding nodes).