DATAGEODE-302 - Add 'nullSafeCount(:Stream)' utility method to StreamUtils.

Additionally, adds another test case to assert the 'concat(:Stream[])' utility method is null-safe when passed a null Stream array.

Renames StreamUtilsTests to StreamUtilsUnitTests.

spring-data-geode/src/main/java/org/springframework/data/gemfire/util/StreamUtils.java

@@ -48,6 +48,19 @@ public abstract class StreamUtils {
 		return concatenatedStream;
 	}
 
+	/**
+	 * Null-safe utility method used to return a {@link Long count} of the number of {@link Object elements}
+	 * in the given {@link Stream}.
+	 *
+	 * @param stream {@link Stream} of {@link Object elements} to count.
+	 * @return a {@link Long count} of the number of {@link Object elements} in the {@link Stream}.
+	 * @see java.util.stream.Stream#count()
+	 * @see #nullSafeStream(Stream)
+	 */
+	public static long nullSafeCount(Stream<?> stream) {
+		return nullSafeStream(stream).count();
+	}
+
 	/**
 	 * Utility method used to guard against {@literal null} {@link Stream Streams}.
 	 *

spring-data-geode/src/test/java/org/springframework/data/gemfire/util/StreamUtilsTests.java

@@ -1,91 +0,0 @@
-/*
- * Copyright 2017-2020 the original author or authors.
- *
- * 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
- *
- *      https://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 org.springframework.data.gemfire.util;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.mockito.Mockito.mock;
-
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
-
-import org.junit.Test;
-
-/**
- * Unit Tests for {@link StreamUtils}.
- *
- * @author John Blum
- * @see java.util.stream.Stream
- * @see org.junit.Test
- * @see org.mockito.Mockito
- * @see org.springframework.data.gemfire.util.StreamUtils
- * @since 2.0.0
- */
-public class StreamUtilsTests {
-
-	@Test
-	@SuppressWarnings("unchecked")
-	public void concatNoStreams() {
-
-		Stream<Object> stream = StreamUtils.concat();
-
-		assertThat(stream).isNotNull();
-		assertThat(stream.count()).isEqualTo(0);
-	}
-
-	@Test
-	@SuppressWarnings("unchecked")
-	public void concatOneStream() {
-
-		Stream<Integer> stream = StreamUtils.concat(Stream.of(1, 2, 3));
-
-		assertThat(stream).isNotNull();
-		assertThat(stream.collect(Collectors.toList())).containsExactly(1, 2, 3);
-	}
-
-	@Test
-	@SuppressWarnings("unchecked")
-	public void concatTwoStreams() {
-
-		Stream<Integer> stream = StreamUtils.concat(Stream.of(1, 2, 3), Stream.of(4, 5, 6));
-
-		assertThat(stream).isNotNull();
-		assertThat(stream.collect(Collectors.toList())).containsExactly(1, 2, 3, 4, 5, 6);
-	}
-
-	@Test
-	@SuppressWarnings("unchecked")
-	public void concatThreeStreams() {
-
-		Stream<Integer> stream =
-			StreamUtils.concat(Stream.of(1, 2, 3), Stream.of(4, 5, 6), Stream.of(7, 8, 9));
-
-		assertThat(stream).isNotNull();
-		assertThat(stream.collect(Collectors.toList())).containsExactly(1, 2, 3, 4, 5, 6, 7, 8, 9);
-	}
-
-	@Test
-	public void nullSafeStreamWithStream() {
-
-		Stream<?> mockStream = mock(Stream.class);
-
-		assertThat(StreamUtils.nullSafeStream(mockStream)).isSameAs(mockStream);
-	}
-
-	@Test
-	public void nullSafeStreamWithNull() {
-		assertThat(StreamUtils.nullSafeStream(null)).isEqualTo(Stream.empty());
-	}
-}

spring-data-geode/src/test/java/org/springframework/data/gemfire/util/StreamUtilsUnitTests.java

@@ -35,6 +35,16 @@ import org.junit.Test;
  */
 public class StreamUtilsUnitTests {
 
+	@Test
+	@SuppressWarnings({ "rawtypes", "unchecked" })
+	public void concatNullStreamArray() {
+
+		Stream stream = StreamUtils.concat((Stream[]) null);
+
+		assertThat(stream).isNotNull();
+		assertThat(stream.count()).isZero();
+	}
+
 	@Test
 	@SuppressWarnings("unchecked")
 	public void concatNoStreams() {
@@ -42,7 +52,7 @@ public class StreamUtilsUnitTests {
 		Stream<Object> stream = StreamUtils.concat();
 
 		assertThat(stream).isNotNull();
-		assertThat(stream.count()).isEqualTo(0);
+		assertThat(stream.count()).isZero();
 	}
 
 	@Test
@@ -76,6 +86,26 @@ public class StreamUtilsUnitTests {
 		assertThat(stream.collect(Collectors.toList())).containsExactly(1, 2, 3, 4, 5, 6, 7, 8, 9);
 	}
 
+	@Test
+	public void countNullStream() {
+		assertThat(StreamUtils.nullSafeCount(null)).isZero();
+	}
+
+	@Test
+	public void countEmptyStream() {
+		assertThat(StreamUtils.nullSafeCount(Stream.empty())).isZero();
+	}
+
+	@Test
+	public void countOneElementStream() {
+		assertThat(StreamUtils.nullSafeCount(Stream.of(1))).isOne();
+	}
+
+	@Test
+	public void countTwoElementStream() {
+		assertThat(StreamUtils.nullSafeCount(Stream.of(1, 2))).isEqualTo(2);
+	}
+
 	@Test
 	public void nullSafeStreamWithStream() {