intellij-sdk-code-samples/simple_language_plugin/src/com/simpleplugin/SimpleTodoIndexer.java

package com.simpleplugin;

import com.intellij.lexer.Lexer;
import com.intellij.psi.impl.cache.impl.OccurrenceConsumer;
import com.intellij.psi.impl.cache.impl.todo.LexerBasedTodoIndexer;

public class SimpleTodoIndexer extends LexerBasedTodoIndexer {
  @Override
  public Lexer createLexer(OccurrenceConsumer consumer) {
    return SimpleIdIndexer.createIndexingLexer(consumer);
  }
}