/*
* Copyright (C) 2015 SoftIndex LLC.
*
* 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 io.datakernel.http;
import io.datakernel.annotation.Nullable;
public final class ExposedLinkedList<T> {
private ExposedLinkedList() {}
public static <T> ExposedLinkedList<T> create() {return new ExposedLinkedList<T>();}
public static final class Node<T> {
final T value;
Node<T> prev;
Node<T> next;
public Node<T> getPrev() {
return prev;
}
public Node<T> getNext() {
return next;
}
public T getValue() {
return value;
}
Node(T value) {
this.value = value;
}
}
private int size;
private Node<T> first;
private Node<T> last;
public Node<T> getFirstNode() {
return first;
}
public Node<T> getLastNode() {
return last;
}
@Nullable
public T getFirstValue() {
return first != null ? first.value : null;
}
@Nullable
public T getLastValue() {
return last != null ? last.value : null;
}
public boolean isEmpty() {
return first == null;
}
public void clear() {
first = null;
last = null;
}
public int size() {
return size;
}
public Node<T> removeFirstNode() {
if (first == null)
return null;
Node<T> node = first;
first = node.next;
if (node.next != null) {
node.next.prev = node.prev;
} else {
assert last == node;
last = node.prev;
}
size--;
node.next = node.prev = null;
return node;
}
public Node<T> removeLastNode() {
if (last == null)
return null;
Node<T> node = last;
last = node.prev;
if (node.prev != null) {
node.prev.next = node.next;
} else {
assert first == node;
first = node.next;
}
size--;
node.next = node.prev = null;
return node;
}
@Nullable
public T removeFirstValue() {
Node<T> node = removeFirstNode();
if (node == null) {
return null;
}
return node.getValue();
}
@Nullable
public T removeLastValue() {
Node<T> node = removeLastNode();
if (node == null) {
return null;
}
return node.getValue();
}
public Node<T> addFirstValue(T value) {
Node<T> node = new Node<>(value);
addFirstNode(node);
return node;
}
public Node<T> addLastValue(T value) {
Node<T> node = new Node<>(value);
addLastNode(node);
return node;
}
public void addFirstNode(Node<T> node) {
assert node.prev == null && node.next == null;
if (first != null) {
assert first.prev == null;
first.prev = node;
node.next = first;
} else {
assert last == null;
last = node;
}
first = node;
size++;
}
public void addLastNode(Node<T> node) {
assert node.prev == null && node.next == null;
if (last != null) {
assert last.next == null;
last.next = node;
node.prev = last;
} else {
assert first == null;
first = node;
}
last = node;
size++;
}
public void moveNodeToLast(Node<T> node) {
if (node.next == null)
return;
removeNode(node);
addLastNode(node);
}
public void moveNodeToFirst(Node<T> node) {
if (node.prev == null)
return;
removeNode(node);
addFirstNode(node);
}
public void removeNode(Node<T> node) {
if (node.prev != null) {
node.prev.next = node.next;
} else {
assert first == node;
first = node.next;
}
if (node.next != null) {
node.next.prev = node.prev;
} else {
assert last == node;
last = node.prev;
}
node.next = node.prev = null;
size--;
}
}