[HUDI-371] Supporting hive combine input format for realtime tables (#1503)

hudi-common/src/main/java/org/apache/hudi/common/util/collection/ArrayUtils.java

@@ -0,0 +1,62 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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
+ *
+ *      http://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.apache.hudi.common.util.collection;
+
+/**
+ * <p>Operations on arrays, primitive arrays (like {@code int[]}) and
+ * primitive wrapper arrays (like {@code Integer[]}).</p>
+ *
+ * <p>This class tries to handle {@code null} input gracefully.
+ * An exception will not be thrown for a {@code null}
+ * array input. However, an Object array that contains a {@code null}
+ * element may throw an exception. Each method documents its behaviour.</p>
+ *
+ * NOTE : Adapted from org.apache.commons.lang3.ArrayUtils
+ */
+public class ArrayUtils {
+
+  /**
+   * An empty immutable {@code long} array.
+   */
+  public static final long[] EMPTY_LONG_ARRAY = new long[0];
+
+  // Long array converters
+  // ----------------------------------------------------------------------
+  /**
+   * <p>Converts an array of object Longs to primitives.</p>
+   *
+   * <p>This method returns {@code null} for a {@code null} input array.</p>
+   *
+   * @param array  a {@code Long} array, may be {@code null}
+   * @return a {@code long} array, {@code null} if null array input
+   * @throws NullPointerException if array content is {@code null}
+   */
+  public static long[] toPrimitive(Long[] array) {
+    if (array == null) {
+      return null;
+    } else if (array.length == 0) {
+      return EMPTY_LONG_ARRAY;
+    }
+    final long[] result = new long[array.length];
+    for (int i = 0; i < array.length; i++) {
+      result[i] = array[i].longValue();
+    }
+    return result;
+  }
+}