* 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
- *
+ *
* 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.
package org.openecomp.sdc.be.dao.utils;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
import java.util.Map.Entry;
-import java.util.Set;
public final class CollectionUtils {
- private CollectionUtils() {
- }
+ private CollectionUtils() {
+ }
- /**
- * Add the content of the 'source' Set to the 'target' set and return the
- * union set.
- *
- * If 'source' is null then a new set is created and returned. If 'target'
- * is null then no content is added to the 'source' Set or newly created
- * set.
- *
- * @param source
- * The Set to merge in the target Set.
- * @param target
- * The Set in which the source set will be merged (through
- * addAll).
- * @return The target Set with addition of source Set elements, or a new Set
- * (including content of source set) if target was null.
- */
- public static <T> Set<T> merge(Set<T> source, Set<T> target) {
- Set<T> merged = new HashSet<T>();
- if (target != null) {
- merged.addAll(target);
- }
- if (source != null) {
- merged.addAll(source);
- }
- return merged.isEmpty() ? null : merged;
- }
+ /**
+ * Add the content of the 'source' Set to the 'target' set and return the
+ * union set.
+ * <p>
+ * If 'source' is null then a new set is created and returned. If 'target'
+ * is null then no content is added to the 'source' Set or newly created
+ * set.
+ *
+ * @param source The Set to merge in the target Set.
+ * @param target The Set in which the source set will be merged (through
+ * addAll).
+ * @return The target Set with addition of source Set elements, or a new Set
+ * (including content of source set) if target was null.
+ */
+ public static <T> Set<T> merge(Set<T> source, Set<T> target) {
+ Set<T> merged = new HashSet<>();
+ if (target != null) {
+ merged.addAll(target);
+ }
+ if (source != null) {
+ merged.addAll(source);
+ }
+ return merged.isEmpty() ? null : merged;
+ }
- /**
- * <p>
- * Add the content of the 'source' Map to the 'target' set and return the
- * union Map.
- * </p>
- * <p>
- * If 'source' is null then a new Map is created and returned. If 'target'
- * is null then no content is added to the 'source' Map or newly created
- * Map.
- * </p>
- *
- * @param source
- * The Map to merge in the target Map.
- * @param target
- * The Map in which the source Map will be merged (through
- * addAll).
- * @param override
- * If an key from the source map already exists in the target
- * map, should it override (true) or not (false) the value.
- * @return The target Map with addition of source Map elements, or a new Map
- * (including content of source set) if target was null.
- */
- public static <T, V> Map<T, V> merge(Map<T, ? extends V> source, Map<T, V> target, boolean override) {
- if (target == null) {
- target = new HashMap();
- }
+ /**
+ * <p>
+ * Add the content of the 'source' Map to the 'target' set and return the
+ * union Map.
+ * </p>
+ * <p>
+ * If 'source' is null then a new Map is created and returned. If 'target'
+ * is null then no content is added to the 'source' Map or newly created
+ * Map.
+ * </p>
+ *
+ * @param source The Map to merge in the target Map.
+ * @param target The Map in which the source Map will be merged (through
+ * addAll).
+ * @param override If an key from the source map already exists in the target
+ * map, should it override (true) or not (false) the value.
+ * @return The target Map with addition of source Map elements, or a new Map
+ * (including content of source set) if target was null.
+ */
+ public static <T, V> Map<T, V> merge(Map<T, ? extends V> source, Map<T, V> target, boolean override) {
+ if (target == null) {
+ target = new HashMap();
+ }
- if (source != null) {
- for (Entry<T, ? extends V> entry : source.entrySet()) {
- if (override || !target.containsKey(entry.getKey())) {
- target.put(entry.getKey(), entry.getValue());
- }
- }
- }
- return target.isEmpty() ? null : target;
- }
+ if (source != null) {
+ for (Entry<T, ? extends V> entry : source.entrySet()) {
+ if (override || !target.containsKey(entry.getKey())) {
+ target.put(entry.getKey(), entry.getValue());
+ }
+ }
+ }
+ return target.isEmpty() ? null : target;
+ }
- /**
- * Merge two lists, the merge is performed based on the contains method so
- * elements presents both in source and target are not added twice to the
- * list.
- *
- * @param source
- * The source list.
- * @param target
- * The target list.
- * @return A list that represents the merged collections.
- */
- public static <T> List<T> merge(List<T> source, List<T> target) {
- List<T> merged = target == null ? new ArrayList<T>() : target;
+ /**
+ * Merge two lists, the merge is performed based on the contains method so
+ * elements presents both in source and target are not added twice to the
+ * list.
+ *
+ * @param source The source list.
+ * @param target The target list.
+ * @return A list that represents the merged collections.
+ */
+ public static <T> List<T> merge(List<T> source, List<T> target) {
+ List<T> merged = target == null ? new ArrayList<>() : target;
- if (source == null) {
- return merged;
- }
+ if (source == null) {
+ return merged;
+ }
- for (T t : source) {
- if (!merged.contains(t)) {
- merged.add(t);
- }
- }
+ for (T t : source) {
+ if (!merged.contains(t)) {
+ merged.add(t);
+ }
+ }
- return merged;
- }
+ return merged;
+ }
+
+ /**
+ * Returns a new list containing the second list appended to the
+ * first list. The {@link List#addAll(Collection)} operation is
+ * used to append the two given lists into a new list.
+ *
+ * @param list1 the first list
+ * @param list2 the second list
+ * @return a new list containing the union of those lists
+ * @throws NullPointerException if either list is null
+ */
+ public static <T> List<T> union(List<T> list1, List<T> list2) {
+ List<T> result = new ArrayList<>(list1);
+ result.addAll(list2);
+ return result;
+ }
}
Code Review / sdc.git / blobdiff