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/*
* Copyright (C) 2007 The Guava Authors
*
* 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 com.google.common.collect.testing;
import java.util.AbstractCollection;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
/**
* A simplistic collection which implements only the bare minimum allowed by the
* spec, and throws exceptions whenever it can.
*
* @author Kevin Bourrillion
*/
public class MinimalCollection<E> extends AbstractCollection<E> {
// TODO: expose allow nulls parameter?
public static <E> MinimalCollection<E> of(E... contents) {
return new MinimalCollection<E>(Object.class, true, contents);
}
// TODO: use this
public static <E> MinimalCollection<E> ofClassAndContents(
Class<? super E> type, E... contents) {
return new MinimalCollection<E>(type, true, contents);
}
private final E[] contents;
private final Class<? super E> type;
private final boolean allowNulls;
// Package-private so that it can be extended.
MinimalCollection(Class<? super E> type, boolean allowNulls, E... contents) {
// TODO: consider making it shuffle the contents to test iteration order.
this.contents = Platform.clone(contents);
this.type = type;
this.allowNulls = allowNulls;
if (!allowNulls) {
for (Object element : contents) {
if (element == null) {
throw new NullPointerException();
}
}
}
}
@Override public int size() {
return contents.length;
}
@Override public boolean contains(Object object) {
if (!allowNulls) {
// behave badly
if (object == null) {
throw new NullPointerException();
}
}
Platform.checkCast(type, object); // behave badly
return Arrays.asList(contents).contains(object);
}
@Override public boolean containsAll(Collection<?> collection) {
if (!allowNulls) {
for (Object object : collection) {
// behave badly
if (object == null) {
throw new NullPointerException();
}
}
}
return super.containsAll(collection);
}
@Override public Iterator<E> iterator() {
return Arrays.asList(contents).iterator();
}
@Override public Object[] toArray() {
Object[] result = new Object[contents.length];
Platform.unsafeArrayCopy(contents, 0, result, 0, contents.length);
return result;
}
/*
* a "type A" unmodifiable collection freaks out proactively, even if there
* wasn't going to be any actual work to do anyway
*/
@Override public boolean addAll(Collection<? extends E> elementsToAdd) {
throw up();
}
@Override public boolean removeAll(Collection<?> elementsToRemove) {
throw up();
}
@Override public boolean retainAll(Collection<?> elementsToRetain) {
throw up();
}
@Override public void clear() {
throw up();
}
private static UnsupportedOperationException up() {
throw new UnsupportedOperationException();
}
}
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