Utility to concatenate streams into one stream

Author: d4gg4d

src/main/java/com/nitorcreations/streams/NStreamsUtils.java

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+package com.nitorcreations.streams;
+
+import java.util.stream.Stream;
+
+public class NStreamsUtils {
+
+    @SafeVarargs
+    public static <T> Stream<T> concat(Stream<T> ...streams) {
+      return Stream.of(streams).reduce(Stream::concat).get();
+    }
+
+}

src/test/java/com/nitorcreations/streams/NStreamsUtilsTest.java

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+package com.nitorcreations.streams;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static java.util.Arrays.asList;
+import static java.util.stream.Collectors.toList;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class NStreamsUtilsTest {
+
+  @Test
+  public void test_concatenation_empty_lists() {
+    List<String> emptylist = new ArrayList<>();
+    List<String> combinedList = NStreamsUtils.concat(emptylist.stream(), emptylist.stream())
+        .collect(toList());
+    assertThat(combinedList).isEmpty();
+  }
+
+  @Test
+  public void test_concatenation() {
+    List<String> list1 = asList("1", "11");
+    List<String> list2 = asList("2", "22");
+    List<String> list3 = asList("3");
+
+    List<String> combinedList = NStreamsUtils.concat(list1.stream(), list2.stream(), list3.stream()).collect(toList());
+    assertThat(combinedList).containsExactly("1","11","2","22","3");
+  }
+}