event/src/main/java/org/apache/karaf/event/service/TopicPredicate.java

/*
 * 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.karaf.event.service;

import java.util.function.Predicate;
import java.util.regex.Pattern;

import org.osgi.service.event.Event;

public class TopicPredicate implements Predicate<Event> {
    private Pattern pattern;

    private TopicPredicate(String topicFilter) {
        pattern = Pattern.compile(topicFilter.replace("*", ".*"));
    }
    
    @Override
    public boolean test(Event event) {
        return pattern.matcher(event.getTopic()).matches();
    }
 
    public static Predicate<Event> matchTopic(String topicFilter) {
        return new TopicPredicate(topicFilter);
    }

}