/*
* Copyright 2007 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;
/**
* Skeletal implementation of the Set interface. <a
* href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/AbstractSet.html">[Sun
* docs]</a>
*
* @param <E> the element type.
*/
public abstract class AbstractSet<E> extends AbstractCollection<E> implements
Set<E> {
@Override
public boolean equals(Object o) {
if (o == this) {
return true;
}
if (!(o instanceof Set)) {
return false;
}
Set<?> other = (Set<?>) o;
if (other.size() != size()) {
return false;
}
for (Iterator<?> iter = other.iterator(); iter.hasNext();) {
Object otherItem = iter.next();
if (!contains(otherItem)) {
return false;
}
}
return true;
}
@Override
public int hashCode() {
int hashCode = 0;
for (Iterator<E> iter = iterator(); iter.hasNext();) {
// Sets can have null members
E next = iter.next();
if (next != null) {
hashCode += next.hashCode();
// handle int overflow by coercing to int
hashCode = ~~hashCode;
}
}
return hashCode;
}
@Override
public boolean removeAll(Collection<?> c) {
int size = size();
if (size < c.size()) {
// If the member of 'this' is in 'c', remove it from 'this'.
//
for (Iterator<E> iter = iterator(); iter.hasNext();) {
E o = iter.next();
if (c.contains(o)) {
iter.remove();
}
}
} else {
// Remove every member of 'c' from 'this'.
//
for (Iterator<?> iter = c.iterator(); iter.hasNext();) {
Object o = iter.next();
remove(o);
}
}
return (size != size());
}
}