Collected.java

/*
 * Copyright (c) 2015 Spotify AB.
 *
 * 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 com.spotify.heroic.common;

/**
 * Interface for objects which merge the functionality of other objects.
 * <p>
 * An empty collected object tends to behave like a null-object, calling methods on them has no
 * effect.
 */
public interface Collected {
    /**
     * Indicate if this collected object is empty or not.
     *
     * @return {@code true} if this collected object is empty.
     */
    default boolean isEmpty() {
        return false;
    }
}