| /** |
| * 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.cxf.common.util; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Dictionary; |
| import java.util.Enumeration; |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| public final class CollectionUtils { |
| private CollectionUtils() { |
| |
| } |
| |
| public static <T> Collection<T> diff(Collection<T> c1, Collection<T> c2) { |
| if (c1 == null || c1.isEmpty() || c2 == null || c2.isEmpty()) { |
| return c1; |
| } |
| Collection<T> difference = new ArrayList<>(); |
| for (T item : c1) { |
| if (!c2.contains(item)) { |
| difference.add(item); |
| } |
| } |
| return difference; |
| } |
| |
| public static <T> boolean isEmpty(Collection<T> c) { |
| if (c != null && !c.isEmpty()) { |
| for (T item : c) { |
| if (item != null) { |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| public static <K, V> boolean isEmpty(Map<K, V> m) { |
| return m == null || m.isEmpty(); |
| } |
| |
| public static <S, T> Dictionary<S, T> singletonDictionary(S s, T t) { |
| return toDictionary(Collections.singletonMap(s, t)); |
| } |
| |
| public static <S, T> Dictionary<S, T> toDictionary(Map<S, T> map) { |
| return new MapToDictionary<>(map); |
| } |
| |
| static class MapToDictionary<S, T> extends Dictionary<S, T> { |
| /** |
| * Map source. |
| **/ |
| private final Map<S, T> map; |
| |
| MapToDictionary(Map<S, T> map) { |
| this.map = map; |
| } |
| |
| |
| public Enumeration<T> elements() { |
| return map != null ? new IteratorToEnumeration<>(map.values().iterator()) : null; |
| } |
| |
| public T get(Object key) { |
| return map != null ? map.get(key) : null; |
| } |
| |
| public boolean isEmpty() { |
| return map == null || map.isEmpty(); |
| } |
| |
| public Enumeration<S> keys() { |
| return map != null ? new IteratorToEnumeration<>(map.keySet().iterator()) : null; |
| } |
| |
| public T put(S key, T value) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public T remove(Object key) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public int size() { |
| return map != null ? map.size() : 0; |
| } |
| |
| static class IteratorToEnumeration<X> implements Enumeration<X> { |
| private final Iterator<X> iter; |
| |
| IteratorToEnumeration(Iterator<X> iter) { |
| this.iter = iter; |
| } |
| |
| public boolean hasMoreElements() { |
| return iter != null && iter.hasNext(); |
| } |
| |
| public X nextElement() { |
| return iter != null ? iter.next() : null; |
| } |
| } |
| } |
| } |