code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * 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.
   */
  
  package io.reactivex.rxjava3.validators;
  
  import java.io.*;
  import java.util.*;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  /**
   * Adds license header to java files.
   */
  public class TextualAorAn {
  
      @Test
      public void checkFiles() throws Exception {
          File f = TestHelper.findSource("Flowable");
          if (f == null) {
              return;
          }
  
          Queue<File> dirs = new ArrayDeque<>();
  
          File parent = f.getParentFile().getParentFile();
          dirs.offer(parent);
  //        dirs.offer(new File(parent.getAbsolutePath().replace('\\', '/').replace("src/main/java", "src/perf/java")));
  //        dirs.offer(new File(parent.getAbsolutePath().replace('\\', '/').replace("src/main/java", "src/test/java")));
  
          StringBuilder fail = new StringBuilder();
  
          while (!dirs.isEmpty()) {
              f = dirs.poll();
  
              File[] list = f.listFiles();
              if (list != null && list.length != 0) {
  
                  for (File u : list) {
                      if (u.isDirectory()) {
                          dirs.offer(u);
                      } else {
                          if (u.getName().endsWith(".java")) {
  
                              List<String> lines = new ArrayList<>();
                              BufferedReader in = new BufferedReader(new FileReader(u));
                              try {
                                  for (;;) {
                                      String line = in.readLine();
                                      if (line == null) {
                                          break;
                                      }
  
                                      lines.add(line);
                                  }
                              } finally {
                                  in.close();
                              }
  
                              String clazz = u.getAbsolutePath().replace('\\', '/');
                              int idx = clazz.indexOf("/io/reactivex/");
                              clazz = clazz.substring(idx + 14).replace(".java", "");
  
                              processFile(fail, lines, clazz, u.getName());
                          }
                      }
                  }
              }
          }
  
          if (fail.length() != 0) {
              System.out.println(fail);
              throw new AssertionError(fail.toString());
          }
      }
  
      static void processFile(StringBuilder b, List<String> lines, String className, String fileName) {
          int i = 1;
          for (String s : lines) {
  
              if (s.contains(" a Observer")) {
                  b.append("java.lang.RuntimeException: ' a Observer'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains("A Observer")) {
                  b.append("java.lang.RuntimeException: 'A Observer'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains(" a Observable")) {
                  b.append("java.lang.RuntimeException: ' a Observable'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains("A Observable")) {
                  b.append("java.lang.RuntimeException: 'A Observable'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains(" an Subscriber")) {
                  b.append("java.lang.RuntimeException: ' an Subscriber'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains("An Subscriber")) {
                  b.append("java.lang.RuntimeException: 'An Subscriber'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains(" an Publisher")) {
                  b.append("java.lang.RuntimeException: ' an Publisher'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains("An Publisher")) {
                  b.append("java.lang.RuntimeException: 'An Publisher'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains(" an Flowable")) {
                  b.append("java.lang.RuntimeException: ' an Flowable'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains("An Flowable")) {
                  b.append("java.lang.RuntimeException: 'An Flowable'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains(" an Single")) {
                  b.append("java.lang.RuntimeException: ' an Single'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains("An Single")) {
                  b.append("java.lang.RuntimeException: 'An Single'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains(" an Maybe")) {
                  b.append("java.lang.RuntimeException: ' an Maybe'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains("An Maybe")) {
                  b.append("java.lang.RuntimeException: 'An Maybe'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains(" an Completable")) {
                  b.append("java.lang.RuntimeException: ' an Completable'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains("An Completable")) {
                  b.append("java.lang.RuntimeException: 'An Completable'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              if (s.contains(" an cancel")) {
                  b.append("java.lang.RuntimeException: ' an cancel'\r\n at io.reactivex.")
                  .append(className).append(" (").append(fileName).append(":").append(i).append(")\r\n");
                  ;
              }
  
              i++;
          }
      }
  }
  