vinothchandar commented on a change in pull request #1159: [HUDI-479] Eliminate or Minimize use of Guava if possible URL: https://github.com/apache/incubator-hudi/pull/1159#discussion_r398322800
########## File path: hudi-common/src/main/java/org/apache/hudi/common/util/CollectionUtils.java ########## @@ -0,0 +1,132 @@ +/* + * 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; + +import java.util.Collections; +import java.util.Iterator; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.Set; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +public class CollectionUtils { + /** + * Determines whether two iterators contain equal elements in the same order. More specifically, + * this method returns {@code true} if {@code iterator1} and {@code iterator2} contain the same + * number of elements and every element of {@code iterator1} is equal to the corresponding element + * of {@code iterator2}. + * + * <p>Note that this will modify the supplied iterators, since they will have been advanced some + * number of elements forward. + */ + public static boolean elementsEqual(Iterator<?> iterator1, Iterator<?> iterator2) { + while (iterator1.hasNext()) { + if (!iterator2.hasNext()) { + return false; + } + Object o1 = iterator1.next(); + Object o2 = iterator2.next(); + if (!Objects.equals(o1, o2)) { + return false; + } + } + return !iterator2.hasNext(); + } + + @SafeVarargs + public static <T> Set<T> createSetFromElements(final T... elements) { + return Stream.of(elements).collect(Collectors.toSet()); + } + + public static <K,V> Map<K, V> createImmutableMap(final K key, final V value) { + return Collections.unmodifiableMap(Collections.singletonMap(key, value)); + } + + @SafeVarargs + public static <T> List<T> createImmutableList(final T... elements) { + return Collections.unmodifiableList(Stream.of(elements).collect(Collectors.toList())); + } + + public static <K,V> Map<K,V> createImmutableMap(final Map<K,V> map) { + return Collections.unmodifiableMap(map); + } + + @SafeVarargs + public static <T> Set<T> createImmutableSet(final T... elements) { + return Collections.unmodifiableSet(Stream.of(elements).collect(Collectors.toSet())); + } + + public static <T> Set<T> createImmutableSet(final Set<T> set) { + return Collections.unmodifiableSet(set); + } + + public static <T> List<T> createImmutableList(final List<T> list) { + return Collections.unmodifiableList(list); + } + + private static Object[] checkElementsNotNull(Object... array) { + return checkElementsNotNull(array, array.length); + } + + private static Object[] checkElementsNotNull(Object[] array, int length) { + for (int i = 0; i < length; i++) { + checkElementNotNull(array[i], i); + } + return array; + } + + private static Object checkElementNotNull(Object element, int index) { + if (element == null) { + throw new NullPointerException("at index " + index); + } + return element; + } + + public static class Maps { Review comment: I am wondering if we can eliminate the need for this class and the builder class, but replacing with plain hashmaps inline? - in places where a static HashMap is needed we can use the map initialization syntax I pasted above. Don't feel very strongly about this,, but thinking if we can avoid builder patterns where it actually is not used that way. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
