| /* |
| * Copyright (C) 2010 The Android Open Source Project |
| * Copyright (C) 2012 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 com.google.gson.internal; |
| |
| import java.io.IOException; |
| import java.io.InvalidObjectException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectStreamException; |
| import java.io.Serializable; |
| import java.util.AbstractMap; |
| import java.util.AbstractSet; |
| import java.util.Comparator; |
| import java.util.ConcurrentModificationException; |
| import java.util.Iterator; |
| import java.util.LinkedHashMap; |
| import java.util.NoSuchElementException; |
| import java.util.Set; |
| |
| /** |
| * A map of comparable keys to values. Unlike {@code TreeMap}, this class uses |
| * insertion order for iteration order. Comparison order is only used as an |
| * optimization for efficient insertion and removal. |
| * |
| * <p>This implementation was derived from Android 4.1's TreeMap class. |
| */ |
| public final class LinkedTreeMap<K, V> extends AbstractMap<K, V> implements Serializable { |
| @SuppressWarnings({ "unchecked", "rawtypes" }) // to avoid Comparable<Comparable<Comparable<...>>> |
| private static final Comparator<Comparable> NATURAL_ORDER = new Comparator<Comparable>() { |
| @Override public int compare(Comparable a, Comparable b) { |
| return a.compareTo(b); |
| } |
| }; |
| |
| Comparator<? super K> comparator; |
| Node<K, V> root; |
| int size = 0; |
| int modCount = 0; |
| |
| // Used to preserve iteration order |
| final Node<K, V> header = new Node<>(); |
| |
| /** |
| * Create a natural order, empty tree map whose keys must be mutually |
| * comparable and non-null. |
| */ |
| @SuppressWarnings("unchecked") // unsafe! this assumes K is comparable |
| public LinkedTreeMap() { |
| this((Comparator<? super K>) NATURAL_ORDER); |
| } |
| |
| /** |
| * Create a tree map ordered by {@code comparator}. This map's keys may only |
| * be null if {@code comparator} permits. |
| * |
| * @param comparator the comparator to order elements with, or {@code null} to |
| * use the natural ordering. |
| */ |
| @SuppressWarnings({ "unchecked", "rawtypes" }) // unsafe! if comparator is null, this assumes K is comparable |
| public LinkedTreeMap(Comparator<? super K> comparator) { |
| this.comparator = comparator != null |
| ? comparator |
| : (Comparator) NATURAL_ORDER; |
| } |
| |
| @Override public int size() { |
| return size; |
| } |
| |
| @Override public V get(Object key) { |
| Node<K, V> node = findByObject(key); |
| return node != null ? node.value : null; |
| } |
| |
| @Override public boolean containsKey(Object key) { |
| return findByObject(key) != null; |
| } |
| |
| @Override public V put(K key, V value) { |
| if (key == null) { |
| throw new NullPointerException("key == null"); |
| } |
| Node<K, V> created = find(key, true); |
| V result = created.value; |
| created.value = value; |
| return result; |
| } |
| |
| @Override public void clear() { |
| root = null; |
| size = 0; |
| modCount++; |
| |
| // Clear iteration order |
| Node<K, V> header = this.header; |
| header.next = header.prev = header; |
| } |
| |
| @Override public V remove(Object key) { |
| Node<K, V> node = removeInternalByKey(key); |
| return node != null ? node.value : null; |
| } |
| |
| /** |
| * Returns the node at or adjacent to the given key, creating it if requested. |
| * |
| * @throws ClassCastException if {@code key} and the tree's keys aren't |
| * mutually comparable. |
| */ |
| Node<K, V> find(K key, boolean create) { |
| Comparator<? super K> comparator = this.comparator; |
| Node<K, V> nearest = root; |
| int comparison = 0; |
| |
| if (nearest != null) { |
| // Micro-optimization: avoid polymorphic calls to Comparator.compare(). |
| @SuppressWarnings("unchecked") // Throws a ClassCastException below if there's trouble. |
| Comparable<Object> comparableKey = (comparator == NATURAL_ORDER) |
| ? (Comparable<Object>) key |
| : null; |
| |
| while (true) { |
| comparison = (comparableKey != null) |
| ? comparableKey.compareTo(nearest.key) |
| : comparator.compare(key, nearest.key); |
| |
| // We found the requested key. |
| if (comparison == 0) { |
| return nearest; |
| } |
| |
| // If it exists, the key is in a subtree. Go deeper. |
| Node<K, V> child = (comparison < 0) ? nearest.left : nearest.right; |
| if (child == null) { |
| break; |
| } |
| |
| nearest = child; |
| } |
| } |
| |
| // The key doesn't exist in this tree. |
| if (!create) { |
| return null; |
| } |
| |
| // Create the node and add it to the tree or the table. |
| Node<K, V> header = this.header; |
| Node<K, V> created; |
| if (nearest == null) { |
| // Check that the value is comparable if we didn't do any comparisons. |
| if (comparator == NATURAL_ORDER && !(key instanceof Comparable)) { |
| throw new ClassCastException(key.getClass().getName() + " is not Comparable"); |
| } |
| created = new Node<>(nearest, key, header, header.prev); |
| root = created; |
| } else { |
| created = new Node<>(nearest, key, header, header.prev); |
| if (comparison < 0) { // nearest.key is higher |
| nearest.left = created; |
| } else { // comparison > 0, nearest.key is lower |
| nearest.right = created; |
| } |
| rebalance(nearest, true); |
| } |
| size++; |
| modCount++; |
| |
| return created; |
| } |
| |
| @SuppressWarnings("unchecked") |
| Node<K, V> findByObject(Object key) { |
| try { |
| return key != null ? find((K) key, false) : null; |
| } catch (ClassCastException e) { |
| return null; |
| } |
| } |
| |
| /** |
| * Returns this map's entry that has the same key and value as {@code |
| * entry}, or null if this map has no such entry. |
| * |
| * <p>This method uses the comparator for key equality rather than {@code |
| * equals}. If this map's comparator isn't consistent with equals (such as |
| * {@code String.CASE_INSENSITIVE_ORDER}), then {@code remove()} and {@code |
| * contains()} will violate the collections API. |
| */ |
| Node<K, V> findByEntry(Entry<?, ?> entry) { |
| Node<K, V> mine = findByObject(entry.getKey()); |
| boolean valuesEqual = mine != null && equal(mine.value, entry.getValue()); |
| return valuesEqual ? mine : null; |
| } |
| |
| private boolean equal(Object a, Object b) { |
| return a == b || (a != null && a.equals(b)); |
| } |
| |
| /** |
| * Removes {@code node} from this tree, rearranging the tree's structure as |
| * necessary. |
| * |
| * @param unlink true to also unlink this node from the iteration linked list. |
| */ |
| void removeInternal(Node<K, V> node, boolean unlink) { |
| if (unlink) { |
| node.prev.next = node.next; |
| node.next.prev = node.prev; |
| } |
| |
| Node<K, V> left = node.left; |
| Node<K, V> right = node.right; |
| Node<K, V> originalParent = node.parent; |
| if (left != null && right != null) { |
| |
| /* |
| * To remove a node with both left and right subtrees, move an |
| * adjacent node from one of those subtrees into this node's place. |
| * |
| * Removing the adjacent node may change this node's subtrees. This |
| * node may no longer have two subtrees once the adjacent node is |
| * gone! |
| */ |
| |
| Node<K, V> adjacent = (left.height > right.height) ? left.last() : right.first(); |
| removeInternal(adjacent, false); // takes care of rebalance and size-- |
| |
| int leftHeight = 0; |
| left = node.left; |
| if (left != null) { |
| leftHeight = left.height; |
| adjacent.left = left; |
| left.parent = adjacent; |
| node.left = null; |
| } |
| |
| int rightHeight = 0; |
| right = node.right; |
| if (right != null) { |
| rightHeight = right.height; |
| adjacent.right = right; |
| right.parent = adjacent; |
| node.right = null; |
| } |
| |
| adjacent.height = Math.max(leftHeight, rightHeight) + 1; |
| replaceInParent(node, adjacent); |
| return; |
| } else if (left != null) { |
| replaceInParent(node, left); |
| node.left = null; |
| } else if (right != null) { |
| replaceInParent(node, right); |
| node.right = null; |
| } else { |
| replaceInParent(node, null); |
| } |
| |
| rebalance(originalParent, false); |
| size--; |
| modCount++; |
| } |
| |
| Node<K, V> removeInternalByKey(Object key) { |
| Node<K, V> node = findByObject(key); |
| if (node != null) { |
| removeInternal(node, true); |
| } |
| return node; |
| } |
| |
| private void replaceInParent(Node<K, V> node, Node<K, V> replacement) { |
| Node<K, V> parent = node.parent; |
| node.parent = null; |
| if (replacement != null) { |
| replacement.parent = parent; |
| } |
| |
| if (parent != null) { |
| if (parent.left == node) { |
| parent.left = replacement; |
| } else { |
| assert (parent.right == node); |
| parent.right = replacement; |
| } |
| } else { |
| root = replacement; |
| } |
| } |
| |
| /** |
| * Rebalances the tree by making any AVL rotations necessary between the |
| * newly-unbalanced node and the tree's root. |
| * |
| * @param insert true if the node was unbalanced by an insert; false if it |
| * was by a removal. |
| */ |
| private void rebalance(Node<K, V> unbalanced, boolean insert) { |
| for (Node<K, V> node = unbalanced; node != null; node = node.parent) { |
| Node<K, V> left = node.left; |
| Node<K, V> right = node.right; |
| int leftHeight = left != null ? left.height : 0; |
| int rightHeight = right != null ? right.height : 0; |
| |
| int delta = leftHeight - rightHeight; |
| if (delta == -2) { |
| Node<K, V> rightLeft = right.left; |
| Node<K, V> rightRight = right.right; |
| int rightRightHeight = rightRight != null ? rightRight.height : 0; |
| int rightLeftHeight = rightLeft != null ? rightLeft.height : 0; |
| |
| int rightDelta = rightLeftHeight - rightRightHeight; |
| if (rightDelta == -1 || (rightDelta == 0 && !insert)) { |
| rotateLeft(node); // AVL right right |
| } else { |
| assert (rightDelta == 1); |
| rotateRight(right); // AVL right left |
| rotateLeft(node); |
| } |
| if (insert) { |
| break; // no further rotations will be necessary |
| } |
| |
| } else if (delta == 2) { |
| Node<K, V> leftLeft = left.left; |
| Node<K, V> leftRight = left.right; |
| int leftRightHeight = leftRight != null ? leftRight.height : 0; |
| int leftLeftHeight = leftLeft != null ? leftLeft.height : 0; |
| |
| int leftDelta = leftLeftHeight - leftRightHeight; |
| if (leftDelta == 1 || (leftDelta == 0 && !insert)) { |
| rotateRight(node); // AVL left left |
| } else { |
| assert (leftDelta == -1); |
| rotateLeft(left); // AVL left right |
| rotateRight(node); |
| } |
| if (insert) { |
| break; // no further rotations will be necessary |
| } |
| |
| } else if (delta == 0) { |
| node.height = leftHeight + 1; // leftHeight == rightHeight |
| if (insert) { |
| break; // the insert caused balance, so rebalancing is done! |
| } |
| |
| } else { |
| assert (delta == -1 || delta == 1); |
| node.height = Math.max(leftHeight, rightHeight) + 1; |
| if (!insert) { |
| break; // the height hasn't changed, so rebalancing is done! |
| } |
| } |
| } |
| } |
| |
| /** |
| * Rotates the subtree so that its root's right child is the new root. |
| */ |
| private void rotateLeft(Node<K, V> root) { |
| Node<K, V> left = root.left; |
| Node<K, V> pivot = root.right; |
| Node<K, V> pivotLeft = pivot.left; |
| Node<K, V> pivotRight = pivot.right; |
| |
| // move the pivot's left child to the root's right |
| root.right = pivotLeft; |
| if (pivotLeft != null) { |
| pivotLeft.parent = root; |
| } |
| |
| replaceInParent(root, pivot); |
| |
| // move the root to the pivot's left |
| pivot.left = root; |
| root.parent = pivot; |
| |
| // fix heights |
| root.height = Math.max(left != null ? left.height : 0, |
| pivotLeft != null ? pivotLeft.height : 0) + 1; |
| pivot.height = Math.max(root.height, |
| pivotRight != null ? pivotRight.height : 0) + 1; |
| } |
| |
| /** |
| * Rotates the subtree so that its root's left child is the new root. |
| */ |
| private void rotateRight(Node<K, V> root) { |
| Node<K, V> pivot = root.left; |
| Node<K, V> right = root.right; |
| Node<K, V> pivotLeft = pivot.left; |
| Node<K, V> pivotRight = pivot.right; |
| |
| // move the pivot's right child to the root's left |
| root.left = pivotRight; |
| if (pivotRight != null) { |
| pivotRight.parent = root; |
| } |
| |
| replaceInParent(root, pivot); |
| |
| // move the root to the pivot's right |
| pivot.right = root; |
| root.parent = pivot; |
| |
| // fixup heights |
| root.height = Math.max(right != null ? right.height : 0, |
| pivotRight != null ? pivotRight.height : 0) + 1; |
| pivot.height = Math.max(root.height, |
| pivotLeft != null ? pivotLeft.height : 0) + 1; |
| } |
| |
| private EntrySet entrySet; |
| private KeySet keySet; |
| |
| @Override public Set<Entry<K, V>> entrySet() { |
| EntrySet result = entrySet; |
| return result != null ? result : (entrySet = new EntrySet()); |
| } |
| |
| @Override public Set<K> keySet() { |
| KeySet result = keySet; |
| return result != null ? result : (keySet = new KeySet()); |
| } |
| |
| static final class Node<K, V> implements Entry<K, V> { |
| Node<K, V> parent; |
| Node<K, V> left; |
| Node<K, V> right; |
| Node<K, V> next; |
| Node<K, V> prev; |
| final K key; |
| V value; |
| int height; |
| |
| /** Create the header entry */ |
| Node() { |
| key = null; |
| next = prev = this; |
| } |
| |
| /** Create a regular entry */ |
| Node(Node<K, V> parent, K key, Node<K, V> next, Node<K, V> prev) { |
| this.parent = parent; |
| this.key = key; |
| this.height = 1; |
| this.next = next; |
| this.prev = prev; |
| prev.next = this; |
| next.prev = this; |
| } |
| |
| @Override public K getKey() { |
| return key; |
| } |
| |
| @Override public V getValue() { |
| return value; |
| } |
| |
| @Override public V setValue(V value) { |
| V oldValue = this.value; |
| this.value = value; |
| return oldValue; |
| } |
| |
| @SuppressWarnings("rawtypes") |
| @Override public boolean equals(Object o) { |
| if (o instanceof Entry) { |
| Entry other = (Entry) o; |
| return (key == null ? other.getKey() == null : key.equals(other.getKey())) |
| && (value == null ? other.getValue() == null : value.equals(other.getValue())); |
| } |
| return false; |
| } |
| |
| @Override public int hashCode() { |
| return (key == null ? 0 : key.hashCode()) |
| ^ (value == null ? 0 : value.hashCode()); |
| } |
| |
| @Override public String toString() { |
| return key + "=" + value; |
| } |
| |
| /** |
| * Returns the first node in this subtree. |
| */ |
| public Node<K, V> first() { |
| Node<K, V> node = this; |
| Node<K, V> child = node.left; |
| while (child != null) { |
| node = child; |
| child = node.left; |
| } |
| return node; |
| } |
| |
| /** |
| * Returns the last node in this subtree. |
| */ |
| public Node<K, V> last() { |
| Node<K, V> node = this; |
| Node<K, V> child = node.right; |
| while (child != null) { |
| node = child; |
| child = node.right; |
| } |
| return node; |
| } |
| } |
| |
| private abstract class LinkedTreeMapIterator<T> implements Iterator<T> { |
| Node<K, V> next = header.next; |
| Node<K, V> lastReturned = null; |
| int expectedModCount = modCount; |
| |
| LinkedTreeMapIterator() { |
| } |
| |
| @Override public final boolean hasNext() { |
| return next != header; |
| } |
| |
| final Node<K, V> nextNode() { |
| Node<K, V> e = next; |
| if (e == header) { |
| throw new NoSuchElementException(); |
| } |
| if (modCount != expectedModCount) { |
| throw new ConcurrentModificationException(); |
| } |
| next = e.next; |
| return lastReturned = e; |
| } |
| |
| @Override public final void remove() { |
| if (lastReturned == null) { |
| throw new IllegalStateException(); |
| } |
| removeInternal(lastReturned, true); |
| lastReturned = null; |
| expectedModCount = modCount; |
| } |
| } |
| |
| class EntrySet extends AbstractSet<Entry<K, V>> { |
| @Override public int size() { |
| return size; |
| } |
| |
| @Override public Iterator<Entry<K, V>> iterator() { |
| return new LinkedTreeMapIterator<Entry<K, V>>() { |
| @Override public Entry<K, V> next() { |
| return nextNode(); |
| } |
| }; |
| } |
| |
| @Override public boolean contains(Object o) { |
| return o instanceof Entry && findByEntry((Entry<?, ?>) o) != null; |
| } |
| |
| @Override public boolean remove(Object o) { |
| if (!(o instanceof Entry)) { |
| return false; |
| } |
| |
| Node<K, V> node = findByEntry((Entry<?, ?>) o); |
| if (node == null) { |
| return false; |
| } |
| removeInternal(node, true); |
| return true; |
| } |
| |
| @Override public void clear() { |
| LinkedTreeMap.this.clear(); |
| } |
| } |
| |
| final class KeySet extends AbstractSet<K> { |
| @Override public int size() { |
| return size; |
| } |
| |
| @Override public Iterator<K> iterator() { |
| return new LinkedTreeMapIterator<K>() { |
| @Override public K next() { |
| return nextNode().key; |
| } |
| }; |
| } |
| |
| @Override public boolean contains(Object o) { |
| return containsKey(o); |
| } |
| |
| @Override public boolean remove(Object key) { |
| return removeInternalByKey(key) != null; |
| } |
| |
| @Override public void clear() { |
| LinkedTreeMap.this.clear(); |
| } |
| } |
| |
| /** |
| * If somebody is unlucky enough to have to serialize one of these, serialize |
| * it as a LinkedHashMap so that they won't need Gson on the other side to |
| * deserialize it. Using serialization defeats our DoS defence, so most apps |
| * shouldn't use it. |
| */ |
| private Object writeReplace() throws ObjectStreamException { |
| return new LinkedHashMap<>(this); |
| } |
| |
| private void readObject(ObjectInputStream in) throws IOException { |
| // Don't permit directly deserializing this class; writeReplace() should have written a replacement |
| throw new InvalidObjectException("Deserialization is unsupported"); |
| } |
| } |