/*
* JBoss, Home of Professional Open Source
* Copyright 2014, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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 org.jboss.weld.util.collections;
import java.io.Serializable;
import java.util.Collections;
import java.util.List;
import java.util.ListIterator;
import java.util.RandomAccess;
/**
* {@link List} implementations optimized for tiny number of elements
*
* @author Jozef Hartinger
*
* @param <E> the element type
*/
abstract class ImmutableTinyList<E> extends ImmutableList<E> implements RandomAccess {
static class Singleton<E> extends ImmutableTinyList<E> implements Serializable {
private static final long serialVersionUID = 1L;
private class SingletonIterator extends Iterators.IndexIterator<E> {
SingletonIterator(int index) {
super(size(), index);
}
@Override
E getElement(int index) {
return element;
}
}
private final E element;
Singleton(E element) {
this.element = element;
}
@Override
public int indexOf(Object o) {
if (o != null && o.equals(element)) {
return 0;
}
return -1;
}
@Override
public int lastIndexOf(Object o) {
return indexOf(o);
}
@Override
public ListIterator<E> listIterator(int index) {
if (index == 0 || index == 1) {
return new SingletonIterator(index);
}
throw indexOutOfBoundsException(index);
}
@Override
public List<E> subList(int fromIndex, int toIndex) {
if (fromIndex < 0 || fromIndex > toIndex) {
throw indexOutOfBoundsException(fromIndex);
}
if (toIndex > size()) {
throw indexOutOfBoundsException(toIndex);
}
if (fromIndex == toIndex) {
return Collections.emptyList();
} else {
return this;
}
}
@Override
public int hashCode() {
return 31 + element.hashCode();
}
@Override
public E get(int index) {
if (index == 0) {
return element;
}
throw indexOutOfBoundsException(index);
}
@Override
public int size() {
return 1;
}
}
}