code: ///////////////////////////////////////////////////////////////////////////////////////////////
  // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
  // Copyright (C) 2001-2023 the original author or authors.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle;
  
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  
  import com.puppycrawl.tools.checkstyle.api.Context;
  
  /**
   * A default implementation of the Context interface.
   */
  public final class DefaultContext implements Context {
  
      /** Stores the context entries. */
      private final Map<String, Object> entries = new HashMap<>();
  
      @Override
      public Object get(String key) {
          return entries.get(key);
      }
  
      @Override
      public Collection<String> getAttributeNames() {
          return new HashSet<>(entries.keySet());
      }
  
      /**
       * Adds a context entry.
       *
       * @param key the context key
       * @param value the value for key
       */
      public void add(String key, Object value) {
          entries.put(key, value);
      }
  
  }
  