content: package ganymede.notebook;
  /*-
   * ##########################################################################
   * Ganymede
   * %%
   * Copyright (C) 2021, 2022 Allen D. Ball
   * %%
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   * ##########################################################################
   */
  import java.io.StringReader;
  import java.util.Objects;
  import java.util.Properties;
  import lombok.NoArgsConstructor;
  import lombok.ToString;
  import lombok.extern.log4j.Log4j2;
  
  import static lombok.AccessLevel.PROTECTED;
  
  /**
   * Abstract {@link Properties} {@link Magic} base class.
   *
   * @author {@link.uri mailto:ball@hcf.dev Allen D. Ball}
   */
  @NoArgsConstructor(access = PROTECTED) @ToString @Log4j2
  public abstract class AbstractPropertiesMagic extends AbstractMagic {
  
      /**
       * Method to convert the cell {@code code} to a {@link Properties}
       * instance.
       *
       * @param   code            The code to parse.
       *
       * @return  The {@link Properties}.
       *
       * @see #HELPER
       */
      protected Properties compile(String code) throws Exception {
          try (var reader = new StringReader(code)) {
              var in = new Properties(System.getProperties());
  
              in.load(reader);
  
              var out = new Properties(in);
              var changed = true;
  
              while (changed) {
                  changed = false;
  
                  for (var key : in.keySet()) {
                      if (key instanceof String) {
                          var string = (String) key;
                          var value = HELPER.replacePlaceholders(in.getProperty(string), out);
  
                          changed |= (! Objects.equals(value, out.put(string, value)));
                      }
                  }
              }
  
              return out;
          }
      }
  }
  