distributedlog-service/src/main/java/com/twitter/distributedlog/service/placement/LoadAppraiser.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 com.twitter.distributedlog.service.placement;

import com.twitter.util.Future;

/**
 * Interface for load appraiser.
 */
public interface LoadAppraiser {
    /**
     * Retrieve the stream load for a given {@code stream}.
     *
     * @param stream name of the stream
     * @return the stream load of the stream.
     */
    Future<StreamLoad> getStreamLoad(String stream);

    /**
     * Refesch the cache.
     * @return
     */
    Future<Void> refreshCache();
}