StreamToLoopInspection: added ExplicitCollectTerminalOperation; StreamVariable simplified; guard checks added (IDEA-CR-15249)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterCollect3.java

@@ -0,0 +1,22 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+public class Main {
+  private static void test(List<String> list) {
+      StringBuilder sb = new StringBuilder();
+      for (String str : list) {
+          if (Objects.nonNull(str)) {
+              sb.append(str);
+          }
+      }
+      String result = sb.toString();
+    System.out.println(result);
+  }
+
+  public static void main(String[] args) {
+    test(Arrays.asList("aa", "bbb", "c", null, "dd"));
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterFlatMapChain.java

@@ -0,0 +1,29 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+
+public class Main {
+  private static long test(List<? extends String> list) {
+      long count = 0;
+      for (Object o : Arrays.<Object>asList(0, null, "1", list)) {
+          for (Object o1 : Arrays.<Object>asList(o)) {
+              for (Object o2 : Arrays.<Object>asList(o1)) {
+                  for (Object o3 : Arrays.<Object>asList(o2)) {
+                      for (Object o4 : Arrays.<Object>asList(o3)) {
+                          for (Object o5 : Arrays.<Object>asList(o4)) {
+                              count++;
+                          }
+                      }
+                  }
+              }
+          }
+      }
+      return count;
+  }
+
+  public static void main(String[] args) {
+    test(Arrays.asList("aa", "bbb", "c", null, "dd"));
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterReusedVar.java

@@ -0,0 +1,19 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.List;
+
+public class Main {
+  private static void test(List<String> list) {
+      long count1 = 0;
+      for (String s : list) {
+          if (!s.isEmpty()) {
+              count1++;
+          }
+      }
+      long count = count1;
+    if(count > 10) {
+      long result = count*2;
+      System.out.println(result);
+    }
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeCollect3.java

@@ -0,0 +1,16 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+public class Main {
+  private static void test(List<String> list) {
+    String result = list.stream().filter(Objects::nonNull).coll<caret>ect(StringBuilder::new, (sb, str) -> sb.append(str), StringBuilder::append).toString();
+    System.out.println(result);
+  }
+
+  public static void main(String[] args) {
+    test(Arrays.asList("aa", "bbb", "c", null, "dd"));
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeFlatMapChain.java

@@ -0,0 +1,15 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+
+public class Main {
+  private static long test(List<? extends String> list) {
+    return Stream.of(0, null, "1", list).flatMap(Stream::of).flatMap(Stream::of).flatMap(Stream::of).flatMap(Stream::of).flatMap(Stream::of).coun<caret>t();
+  }
+
+  public static void main(String[] args) {
+    test(Arrays.asList("aa", "bbb", "c", null, "dd"));
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeReusedVar.java

@@ -0,0 +1,13 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.List;
+
+public class Main {
+  private static void test(List<String> list) {
+    long count = list.stream().filter(s -> !s.isEmpty()).co<caret>unt();
+    if(count > 10) {
+      long result = count*2;
+      System.out.println(result);
+    }
+  }
+}