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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.rocketmq.mqtt.common.model;
import org.apache.rocketmq.mqtt.common.util.TopicUtils;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
public class Trie {
private TrieNode rootNode = new TrieNode(null);
public synchronized V addNode(String key, V nodeValue, K nodeKey) {
try {
String[] keyArray = key.split(Constants.MQTT_TOPIC_DELIMITER);
TrieNode currentNode = rootNode;
int level = 0;
while (level < keyArray.length) {
TrieNode trieNode = currentNode.children.get(keyArray[level]);
if (trieNode == null) {
trieNode = new TrieNode(currentNode);
TrieNode oldNode = currentNode.children.putIfAbsent(keyArray[level], trieNode);
if (oldNode != null) {
trieNode = oldNode;
}
}
level++;
currentNode = trieNode;
}
V old = currentNode.valueSet.put(nodeKey, nodeValue);
return old;
} catch (Throwable e) {
throw new TrieException(e);
}
}
/**
* @param key
* @param valueKey
* @return null if can not find the key and valueKey or return the value
*/
public synchronized V deleteNode(String key, K valueKey) {
try {
String[] keyArray = key.split(Constants.MQTT_TOPIC_DELIMITER);
TrieNode currentNode = rootNode;
int level = 0;
while (level < keyArray.length) {
TrieNode trieNode = currentNode.children.get(keyArray[level]);
if (trieNode == null) {
break;
}
level++;
currentNode = trieNode;
}
V oldValue = currentNode.valueSet.remove(valueKey);
//clean the empty node
while (currentNode.children.isEmpty() && currentNode.valueSet.isEmpty() && currentNode.parentNode != null) {
currentNode.parentNode.children.remove(keyArray[--level]);
currentNode = currentNode.parentNode;
}
return oldValue;
} catch (Throwable e) {
throw new TrieException(e);
}
}
public long countSubRecords() {
return countLevelRecords(rootNode);
}
private long countLevelRecords(TrieNode currentNode) {
if (currentNode == null) {
return 0;
}
if (currentNode.children.isEmpty()) {
return currentNode.valueSet.size();
}
long childrenCount = 0;
for (Map.Entry> entry : currentNode.children.entrySet()) {
childrenCount += countLevelRecords(entry.getValue());
}
return childrenCount + currentNode.valueSet.size();
}
public Map getNode(String key) {
try {
String[] keyArray = key.split(Constants.MQTT_TOPIC_DELIMITER);
Map result = findValueSet(rootNode, keyArray, 0, keyArray.length, false);
return result;
} catch (Throwable e) {
throw new TrieException(e);
}
}
public void traverseAll(TrieMethod method) {
StringBuilder builder = new StringBuilder(128);
traverse(rootNode, method, builder);
}
public Set getNodePath(String key) {
try {
String[] keyArray = key.split(Constants.MQTT_TOPIC_DELIMITER);
StringBuilder builder = new StringBuilder(key.length());
Set result = findValuePath(rootNode, keyArray, 0, keyArray.length, builder, false);
return result;
} catch (Throwable e) {
throw new TrieException(e);
}
}
private Set findValuePath(TrieNode currentNode, String[] topicArray, int level, int maxLevel,
StringBuilder builder, boolean isNumberSign) {
Set result = new HashSet<>();
// match end of path
boolean isPathEnd = (level == maxLevel || isNumberSign) && !currentNode.valueSet.isEmpty() && builder.length() > 0;
if (isPathEnd) {
result.add(TopicUtils.normalizeTopic(builder.toString().substring(0, builder.length() - 1)));
}
// match the '#'
TrieNode numberMatch = currentNode.children.get(Constants.NUMBER_SIGN);
if (numberMatch != null) {
int start = builder.length();
builder.append(Constants.NUMBER_SIGN).append(Constants.MQTT_TOPIC_DELIMITER);
result.addAll(findValuePath(numberMatch, topicArray, level + 1, maxLevel, builder, true));
builder.delete(start, builder.length());
}
// match the mqtt-topic path
if (level < maxLevel && !currentNode.children.isEmpty()) {
// match the precise
TrieNode trieNode = currentNode.children.get(topicArray[level]);
if (trieNode != null) {
int start = builder.length();
builder.append(topicArray[level]).append(Constants.MQTT_TOPIC_DELIMITER);
result.addAll(findValuePath(trieNode, topicArray, level + 1, maxLevel, builder, false));
builder.delete(start, builder.length());
}
// match the '+'
TrieNode plusMatch = currentNode.children.get(Constants.PLUS_SIGN);
if (plusMatch != null) {
int start = builder.length();
builder.append(Constants.PLUS_SIGN).append(Constants.MQTT_TOPIC_DELIMITER);
result.addAll(findValuePath(plusMatch, topicArray, level + 1, maxLevel, builder, false));
builder.delete(start, builder.length());
}
}
return result;
}
private void traverse(TrieNode currentNode, TrieMethod method, StringBuilder builder) {
for (Map.Entry> entry : currentNode.children.entrySet()) {
int start = builder.length();
builder.append(entry.getKey()).append(Constants.MQTT_TOPIC_DELIMITER);
traverse(entry.getValue(), method, builder);
builder.delete(start, builder.length());
}
Iterator> iterator = currentNode.valueSet.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry entry = iterator.next();
try {
method.doMethod(builder.toString(), entry.getKey());
} catch (Throwable e) {
}
}
}
private Map findValueSet(TrieNode currentNode, String[] topicArray, int level, int maxLevel,
boolean isNumberSign) {
Map result = new HashMap<>(16);
// match the mqtt-topic leaf or match the leaf node of trie
if (level == maxLevel || isNumberSign) {
result.putAll(currentNode.valueSet);
}
// match the '#'
TrieNode numberMatch = currentNode.children.get(Constants.NUMBER_SIGN);
if (numberMatch != null) {
result.putAll(findValueSet(numberMatch, topicArray, level + 1, maxLevel, true));
}
// match the mqtt-topic path
if (level < maxLevel && !currentNode.children.isEmpty()) {
// match the precise
TrieNode trieNode = currentNode.children.get(topicArray[level]);
if (trieNode != null) {
result.putAll(findValueSet(trieNode, topicArray, level + 1, maxLevel, false));
}
// match the '+'
TrieNode plusMatch = currentNode.children.get(Constants.PLUS_SIGN);
if (plusMatch != null) {
result.putAll(findValueSet(plusMatch, topicArray, level + 1, maxLevel, false));
}
}
return result;
}
class TrieNode {
public TrieNode parentNode;
public Map> children = new ConcurrentHashMap<>();
public Map valueSet = new ConcurrentHashMap<>();
public TrieNode(TrieNode parentNode) {
this.parentNode = parentNode;
}
}
}
