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;
  
  /**
   * Test verifying there are no 2..5 empty newlines in the code.
   */
  public class TooManyEmptyNewLines {
  
      @Test
      public void tooManyEmptyNewLines2() throws Exception  {
          findPattern(2);
      }
  
      @Test
      public void tooManyEmptyNewLines3() throws Exception  {
          findPattern(3);
      }
  
      @Test
      public void tooManyEmptyNewLines4() throws Exception  {
          findPattern(4);
      }
  
      @Test
      public void tooManyEmptyNewLines5() throws Exception  {
          findPattern(5);
      }
  
      static void findPattern(int newLines) throws Exception {
          File f = TestHelper.findSource("Flowable");
          if (f == null) {
              System.out.println("Unable to find sources of TestHelper.findSourceDir()");
              return;
          }
  
          Queue<File> dirs = new ArrayDeque<>();
  
          StringBuilder fail = new StringBuilder();
          fail.append("The following code pattern was found: ");
          fail.append("\\R");
          for (int i = 0; i < newLines; i++) {
              fail.append("\\R");
          }
          fail.append("\n");
  
          File parent = f.getParentFile().getParentFile();
  
          dirs.offer(new File(parent.getAbsolutePath().replace('\\', '/')));
          dirs.offer(new File(parent.getAbsolutePath().replace('\\', '/').replace("src/main/java", "src/test/java")));
  
          int total = 0;
  
          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 {
                          String fname = u.getName();
                          if (fname.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();
                              }
  
                              for (int i = 0; i < lines.size() - newLines; i++) {
                                  String line1 = lines.get(i);
                                  if (line1.isEmpty()) {
                                      int c = 1;
                                      for (int j = i + 1; j < lines.size(); j++) {
                                          if (lines.get(j).trim().isEmpty()) {
                                              c++;
                                          } else {
                                              break;
                                          }
                                      }
  
                                      if (c == newLines) {
                                          fail
                                          .append(fname)
                                          .append("#L").append(i + 1)
                                          .append("\n")
                                          .append(" at ")
                                          .append(fname.replace(".java", ""))
                                          .append(".method(")
                                          .append(fname)
                                          .append(":").append(i + 1)
                                          .append(")\n")
                                          ;
                                          total++;
                                          i += c;
                                      }
                                  }
                              }
                          }
                      }
                  }
              }
          }
          if (total != 0) {
              fail.insert(0, "Found " + total + " instances\n");
              System.out.println(fail);
              throw new AssertionError(fail.toString());
          }
      }
  }
  