log4j2-api/src/main/java/org/apache/logging/log4j/Marker.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.logging.log4j;

import java.io.Serializable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 */
public class Marker implements Serializable {

    private static ConcurrentMap<String, Marker> markerMap = new ConcurrentHashMap<String, Marker>();

    public static Marker getMarker(String name) {
        markerMap.putIfAbsent(name, new Marker(name));
        return markerMap.get(name);
    }

    public static Marker getMarker(String name, String parent) {
        Marker parentMarker = markerMap.get(parent);
        if (parentMarker == null) {
            throw new IllegalArgumentException("Parent Marker " + parent + " has not been defined");
        }
        return getMarker(name, parentMarker);
    }

    public static Marker getMarker(String name, Marker parent) {
        markerMap.putIfAbsent(name, new Marker(name, parent));
        return markerMap.get(name);
    }

    private String name;
    private Marker parent;

    private Marker(String name) {
        this.name = name;
    }

    private Marker(String name, Marker parent) {
        this.name = name;
        this.parent = parent;
    }

    public String getName() {
        return this.name;
    }

    public Marker getParent() {
        return this.parent;
    }

    public boolean isInstanceOf(Marker m) {
        if (m == null) {
            throw new IllegalArgumentException("A marker parameter is required");
        }
        Marker test = this;
        do {
            if (test == m) {
                return true;
            }
            test = test.getParent();
        } while (test != null);
        return false;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        Marker marker = (Marker) o;

        if (name != null ? !name.equals(marker.name) : marker.name != null) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        return name != null ? name.hashCode() : 0;
    }
}