Merge pull request into develop from feature/custom-collector-for-mylist

2026-08-31 15:20:43 +04:00
parent 43c2713d68 36baf54498
commit d627b03815
6 changed files with 236 additions and 0 deletions
@@ -0,0 +1,10 @@
+package ru.test.maven.spring;
+import java.util.stream.Collector;
+public class MyCollectors
+{
+    private MyCollectors() {
+    }
+    public static <T> Collector<T, MyList<T>, MyList<T>> toMyList() {
+        return new MyListCollector<>();
+    }
+}
@@ -0,0 +1,41 @@
+package ru.test.maven.spring;
+import java.util.Collections;
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.BinaryOperator;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+public class MyListCollector <T> implements Collector<T, MyList<T>, MyList<T>>
+{
+    @Override
+    public Supplier<MyList<T>> supplier()
+    {
+        return () -> new MyLinkedList<>();
+    }
+    @Override
+    public BiConsumer<MyList<T>, T> accumulator() {
+
+        return (list, element) -> list.add(element);
+    }
+    @Override
+    public BinaryOperator<MyList<T>> combiner() {
+        return (list1, list2) -> {
+            for (int i = 0; i < list2.size(); i++) {
+                list1.add(list2.get(i));
+            }
+            return list1;
+        };
+    }
+    @Override
+    public Function<MyList<T>, MyList<T>> finisher()
+    {
+        return list -> list;
+    }
+    @Override
+    public Set<Collector.Characteristics> characteristics() {
+        return java.util.Set.of(
+                Collector.Characteristics.IDENTITY_FINISH
+        );
+    }
+}
@@ -0,0 +1,15 @@
+package ru.project.collectors;
+import java.util.stream.Collector;
+
+public class MyCollectors
+{
+    private MyCollectors() {
+
+    }
+
+    public static <T> Collector<T, MyList<T>, MyList<T>> toMyList()
+    {
+        return new MyListCollector<>();
+
+    }
+}
@@ -0,0 +1,43 @@
+package ru.project.collectors;
+import java.util.Collections;
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.BinaryOperator;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+public class MyListCollector <T> implements Collector<T, MyList<T>, MyList<T>>
+{
+    @Override
+    public Supplier<MyList<T>> supplier()
+    {
+        return () -> new MyLinkedList<>();
+    }
+
+    @Override
+    public BiConsumer<MyList<T>, T> accumulator() {
+
+        return (list, element) -> list.add(element);
+    }
+
+    @Override
+    public BinaryOperator<MyList<T>> combiner() {
+        return (list1, list2) -> {
+            list1.addAll(list2);
+            return list1;
+        };
+    }
+
+    @Override
+    public Function<MyList<T>, MyList<T>> finisher()
+    {
+        return list -> list;
+    }
+
+    @Override
+    public Set<Collector.Characteristics> characteristics() {
+        return java.util.Set.of(
+                Collector.Characteristics.IDENTITY_FINISH
+        );
+    }
+}
@@ -0,0 +1,63 @@
+package ru.test.maven.spring;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+import java.util.Set;
+import java.util.stream.Collector;
+import java.util.stream.IntStream;
+import java.util.Collections;
+public class MyListCollectorTest
+{
+    private final MyListCollector<Integer> collector = new MyListCollector<>();
+
+    @Test
+    void shouldTestCollectInOrderSequential() {
+        MyList<Integer> result = IntStream.range(0, 10)
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(10, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+
+    }
+
+    @Test
+    void shouldTestCollectInOrderParallel() {
+        MyList<Integer> result = IntStream.range(0, 100)
+                .parallel()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(100, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+    }
+
+    @Test
+    void shouldTestHandleEmptyStream() {
+        MyList<Integer> result = IntStream.empty()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertTrue(result.isEmpty());
+
+    }
+    @Test
+    void shouldTestNotUseStandardList() {
+        MyList<String> result = IntStream.range(0, 5)
+                .mapToObj(i -> "item" + i)
+                .collect(MyCollectors.toMyList());
+
+        assertInstanceOf(MyList.class, result);
+        assertFalse(result instanceof java.util.List);
+    }
+    @Test
+    void shouldTestHaveCorrectCharacteristics() {
+        Set<Collector.Characteristics> characteristics = collector.characteristics();
+        assertTrue(characteristics.contains(java.util.stream.Collector.Characteristics.IDENTITY_FINISH));
+        assertFalse(characteristics.contains(java.util.stream.Collector.Characteristics.UNORDERED));
+    }
+
+}
@@ -0,0 +1,64 @@
+package ru.test.maven.spring;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+import java.util.Set;
+import java.util.stream.Collector;
+import java.util.stream.IntStream;
+import java.util.Collections;
+
+public class MyListCollectorTest
+{
+    private final MyListCollector<Integer> collector = new MyListCollector<>();
+
+    @Test
+    void shouldTestCollectInOrderSequential() {
+        MyList<Integer> result = IntStream.range(0, 10)
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(10, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+
+    }
+
+    @Test
+    void shouldTestCollectInOrderParallel() {
+        MyList<Integer> result = IntStream.range(0, 100)
+                .parallel()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(100, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+    }
+
+    @Test
+    void shouldTestHandleEmptyStream() {
+        MyList<Integer> result = IntStream.empty()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertTrue(result.isEmpty());
+
+    }
+    @Test
+    void shouldTestNotUseStandardList() {
+        MyList<String> result = IntStream.range(0, 5)
+                .mapToObj(i -> "item" + i)
+                .collect(MyCollectors.toMyList());
+
+        assertInstanceOf(MyList.class, result);
+        assertFalse(result instanceof java.util.List);
+    }
+    @Test
+    void shouldTestHaveCorrectCharacteristics() {
+        Set<Collector.Characteristics> characteristics = collector.characteristics();
+        assertTrue(characteristics.contains(java.util.stream.Collector.Characteristics.IDENTITY_FINISH));
+        assertFalse(characteristics.contains(java.util.stream.Collector.Characteristics.UNORDERED));
+    }
+
+}