/*
* 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.kafka.common.internals;
import org.apache.kafka.common.errors.InvalidTopicException;
import org.apache.kafka.common.utils.Utils;
import java.util.Collections;
import java.util.Set;
import java.util.regex.Pattern;
public class Topic {
public static final String GROUP_METADATA_TOPIC_NAME = "__consumer_offsets";
public static final String TRANSACTION_STATE_TOPIC_NAME = "__transaction_state";
public static final String LEGAL_CHARS = "[a-zA-Z0-9._-]";
private static final Set<String> INTERNAL_TOPICS = Collections.unmodifiableSet(
Utils.mkSet(GROUP_METADATA_TOPIC_NAME, TRANSACTION_STATE_TOPIC_NAME));
private static final int MAX_NAME_LENGTH = 249;
private static final Pattern LEGAL_CHARS_PATTERN = Pattern.compile(LEGAL_CHARS + "+");
public static void validate(String topic) {
if (topic.isEmpty())
throw new InvalidTopicException("Topic name is illegal, it can't be empty");
if (topic.equals(".") || topic.equals(".."))
throw new InvalidTopicException("Topic name cannot be \".\" or \"..\"");
if (topic.length() > MAX_NAME_LENGTH)
throw new InvalidTopicException("Topic name is illegal, it can't be longer than " + MAX_NAME_LENGTH +
" characters, topic name: " + topic);
if (!containsValidPattern(topic))
throw new InvalidTopicException("Topic name \"" + topic + "\" is illegal, it contains a character other than " +
"ASCII alphanumerics, '.', '_' and '-'");
}
public static boolean isInternal(String topic) {
return INTERNAL_TOPICS.contains(topic);
}
/**
* Due to limitations in metric names, topics with a period ('.') or underscore ('_') could collide.
*
* @param topic The topic to check for colliding character
* @return true if the topic has collision characters
*/
public static boolean hasCollisionChars(String topic) {
return topic.contains("_") || topic.contains(".");
}
/**
* Returns true if the topicNames collide due to a period ('.') or underscore ('_') in the same position.
*
* @param topicA A topic to check for collision
* @param topicB A topic to check for collision
* @return true if the topics collide
*/
public static boolean hasCollision(String topicA, String topicB) {
return topicA.replace('.', '_').equals(topicB.replace('.', '_'));
}
/**
* Valid characters for Kafka topics are the ASCII alphanumerics, '.', '_', and '-'
*/
static boolean containsValidPattern(String topic) {
return LEGAL_CHARS_PATTERN.matcher(topic).matches();
}
}