| /* |
| * Copyright 2008 Google Inc. |
| * |
| * 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. See the |
| * License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| package java.util; |
| |
| import static javaemul.internal.InternalPreconditions.checkNotNull; |
| |
| import javaemul.internal.ArrayHelper; |
| |
| /** |
| * Skeletal implementation of the Collection interface. <a |
| * href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/AbstractCollection.html">[Sun |
| * docs]</a> |
| * |
| * @param <E> the element type. |
| * |
| */ |
| public abstract class AbstractCollection<E> implements Collection<E> { |
| |
| protected AbstractCollection() { |
| } |
| |
| @Override |
| public boolean add(E o) { |
| throw new UnsupportedOperationException("Add not supported on this collection"); |
| } |
| |
| @Override |
| public boolean addAll(Collection<? extends E> c) { |
| checkNotNull(c); |
| |
| boolean changed = false; |
| for (E e : c) { |
| changed |= add(e); |
| } |
| return changed; |
| } |
| |
| @Override |
| public void clear() { |
| for (Iterator<E> iter = iterator(); iter.hasNext();) { |
| iter.next(); |
| iter.remove(); |
| } |
| } |
| |
| @Override |
| public boolean contains(Object o) { |
| return advanceToFind(o, false); |
| } |
| |
| @Override |
| public boolean containsAll(Collection<?> c) { |
| checkNotNull(c); |
| |
| for (Object e : c) { |
| if (!contains(e)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| return size() == 0; |
| } |
| |
| @Override |
| public boolean remove(Object o) { |
| return advanceToFind(o, true); |
| } |
| |
| @Override |
| public boolean removeAll(Collection<?> c) { |
| checkNotNull(c); |
| |
| boolean changed = false; |
| for (Iterator<?> iter = iterator(); iter.hasNext();) { |
| Object o = iter.next(); |
| if (c.contains(o)) { |
| iter.remove(); |
| changed = true; |
| } |
| } |
| return changed; |
| } |
| |
| @Override |
| public boolean retainAll(Collection<?> c) { |
| checkNotNull(c); |
| |
| boolean changed = false; |
| for (Iterator<?> iter = iterator(); iter.hasNext();) { |
| Object o = iter.next(); |
| if (!c.contains(o)) { |
| iter.remove(); |
| changed = true; |
| } |
| } |
| return changed; |
| } |
| |
| @Override |
| public Object[] toArray() { |
| return toArray(new Object[size()]); |
| } |
| |
| @Override |
| public <T> T[] toArray(T[] a) { |
| int size = size(); |
| if (a.length < size) { |
| a = ArrayHelper.createFrom(a, size); |
| } |
| Object[] result = a; |
| Iterator<E> it = iterator(); |
| for (int i = 0; i < size; ++i) { |
| result[i] = it.next(); |
| } |
| if (a.length > size) { |
| a[size] = null; |
| } |
| return a; |
| } |
| |
| @Override |
| public String toString() { |
| StringJoiner joiner = new StringJoiner(", ", "[", "]"); |
| for (E e : this) { |
| joiner.add(e == this ? "(this Collection)" : String.valueOf(e)); |
| } |
| return joiner.toString(); |
| } |
| |
| private boolean advanceToFind(Object o, boolean remove) { |
| for (Iterator<E> iter = iterator(); iter.hasNext();) { |
| E e = iter.next(); |
| if (Objects.equals(o, e)) { |
| if (remove) { |
| iter.remove(); |
| } |
| return true; |
| } |
| } |
| return false; |
| } |
| } |