IDEA-187214 Stream to loop inspection: support Java 10 toUnmodifiableList/Set/Map

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterJava10ImmutableCollector.java

@@ -0,0 +1,47 @@
+// "Fix all 'Stream API call chain can be replaced with loop' problems in file" "true"
+package java.util.stream;
+
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+class Collectors {
+  public static native <T> Collector<T, ?, List<T>> toUnmodifiableList();
+  public static native <T> Collector<T, ?, Set<T>> toUnmodifiableSet();
+  public static native <T, K, U> Collector<T, ?, Map<K,U>> toUnmodifiableMap(Function<? super T, ? extends K> keyMapper, Function<? super T, ? extends U> valueMapper);
+}
+
+class MyFile {
+  public static List<String> testList(String[] args) {
+      List<String> result = new ArrayList<>();
+      for (String arg : args) {
+          if (arg != null) {
+              result.add(arg);
+          }
+      }
+      List<String> list = Collections.unmodifiableList(result);
+    return list;
+  }
+
+  public static Set<String> testSet(String[] args) {
+      Set<String> set = new HashSet<>();
+      for (String arg : args) {
+          if (arg != null) {
+              set.add(arg);
+          }
+      }
+      return Collections.unmodifiableSet(set);
+  }
+
+  public static Map<String, String> testMap(String[] args) {
+      Map<String, String> map = new HashMap<>();
+      for (String arg : args) {
+          if (arg != null) {
+              if (map.put(arg.trim(), arg) != null) {
+                  throw new IllegalStateException("Duplicate key");
+              }
+          }
+      }
+      return Collections.unmodifiableMap(map);
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeJava10ImmutableCollector.java

@@ -0,0 +1,30 @@
+// "Fix all 'Stream API call chain can be replaced with loop' problems in file" "true"
+package java.util.stream;
+
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+class Collectors {
+  public static native <T> Collector<T, ?, List<T>> toUnmodifiableList();
+  public static native <T> Collector<T, ?, Set<T>> toUnmodifiableSet();
+  public static native <T, K, U> Collector<T, ?, Map<K,U>> toUnmodifiableMap(Function<? super T, ? extends K> keyMapper, Function<? super T, ? extends U> valueMapper);
+}
+
+class MyFile {
+  public static List<String> testList(String[] args) {
+    List<String> list = Arrays.stream(args).filter(Objects::nonNull)
+                              .collect(Collectors.toUnmodifiab<caret>leList());
+    return list;
+  }
+
+  public static Set<String> testSet(String[] args) {
+    return Arrays.stream(args).filter(Objects::nonNull)
+                 .collect(Collectors.toUnmodifiableSet());
+  }
+
+  public static Map<String, String> testMap(String[] args) {
+    return Arrays.stream(args).filter(Objects::nonNull)
+                 .collect(Collectors.toUnmodifiableMap(String::trim, Function.identity()));
+  }
+}