11. Find Usages Provider

Edit pageLast modified: 19 March 2025

Reference: Find Usages

Code: SimpleFindUsagesProvider

Testing: 8. Find Usages Test

tip

This page is part of multi-step Custom Language Support Tutorial. All previous steps must be executed in sequence for the code to work.

A FindUsagesProvider uses a word scanner to build an index of words in every file. A scanner breaks the text into words and defines the context for each word.

Define a Find Usages Provider

The SimpleFindUsagesProvider implements FindUsagesProvider. Using the DefaultWordsScanner ensures the scanner implementation is thread-safe. See the comments in FindUsagesProvider for more information.

final class SimpleFindUsagesProvider implements FindUsagesProvider {

  @Override
  public WordsScanner getWordsScanner() {
    return new DefaultWordsScanner(new SimpleLexerAdapter(),
        SimpleTokenSets.IDENTIFIERS,
        SimpleTokenSets.COMMENTS,
        TokenSet.EMPTY);
  }

  @Override
  public boolean canFindUsagesFor(@NotNull PsiElement psiElement) {
    return psiElement instanceof PsiNamedElement;
  }

  @Nullable
  @Override
  public String getHelpId(@NotNull PsiElement psiElement) {
    return null;
  }

  @NotNull
  @Override
  public String getType(@NotNull PsiElement element) {
    if (element instanceof SimpleProperty) {
      return "simple property";
    }
    return "";
  }

  @NotNull
  @Override
  public String getDescriptiveName(@NotNull PsiElement element) {
    if (element instanceof SimpleProperty) {
      return ((SimpleProperty) element).getKey();
    }
    return "";
  }

  @NotNull
  @Override
  public String getNodeText(@NotNull PsiElement element, boolean useFullName) {
    if (element instanceof SimpleProperty) {
      return ((SimpleProperty) element).getKey() +
          SimpleAnnotator.SIMPLE_SEPARATOR_STR +
          ((SimpleProperty) element).getValue();
    }
    return "";
  }

}

Register the Find Usages Provider

The SimpleFindUsagesProvider implementation is registered with the IntelliJ Platform in the plugin configuration file using the com.intellij.lang.findUsagesProvider extension point.

<extensions defaultExtensionNs="com.intellij">
  <lang.findUsagesProvider
      language="Simple"
      implementationClass="org.intellij.sdk.language.SimpleFindUsagesProvider"/>
</extensions>

Run the Project

Run the plugin by using the Gradle runIde task.

The IDE now supports Find Usages for any property with a reference:

Find Usages