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11. Find Usages Provider

A find usage provider 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.

11.1. Define a Find Usages Provider
11.2. Register the Find Usages Provider
11.3. Run the Project

11.1. 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.

// Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.

package org.intellij.sdk.language;

import com.intellij.lang.cacheBuilder.*;
import com.intellij.lang.findUsages.FindUsagesProvider;
import com.intellij.psi.*;
import com.intellij.psi.tree.TokenSet;
import org.intellij.sdk.language.psi.SimpleProperty;
import org.intellij.sdk.language.psi.SimpleTypes;
import org.jetbrains.annotations.*;

public class SimpleFindUsagesProvider implements FindUsagesProvider {
  @Nullable
  @Override
  public WordsScanner getWordsScanner() {
    return new DefaultWordsScanner(new SimpleLexerAdapter(),
                                   TokenSet.create(SimpleTypes.KEY),
                                   TokenSet.create(SimpleTypes.COMMENT),
                                   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";
    } else {
      return "";
    }
  }
  
  @NotNull
  @Override
  public String getDescriptiveName(@NotNull PsiElement element) {
    if (element instanceof SimpleProperty) {
      return ((SimpleProperty) element).getKey();
    } else {
      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();
    } else {
      return "";
    }
  }
}

11.2. 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>

11.3. Run the Project

Rebuild the project, and run simple_language_plugin in a Development Instance. The IDE now supports Find Usages for any property with a reference:

Find Usages

Last modified: 19 February 2020