content: /*
   * 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.distributedlog.metadata;
  
  import com.google.common.annotations.Beta;
  import java.net.URI;
  import java.util.Iterator;
  import java.util.Optional;
  import java.util.concurrent.CompletableFuture;
  import org.apache.distributedlog.callback.NamespaceListener;
  
  /**
   * Interface for log metadata store.
   */
  @Beta
  public interface LogMetadataStore {
  
      /**
       * Create a stream and return it is namespace location.
       *
       * @param logName
       *          name of the log
       * @return namespace location that stores this stream.
       */
      CompletableFuture<URI> createLog(String logName);
  
      /**
       * Get the location of the log.
       *
       * @param logName
       *          name of the log
       * @return namespace location that stores this stream.
       */
      CompletableFuture<Optional<URI>> getLogLocation(String logName);
  
      /**
       * Retrieves logs from the namespace.
       *
       * @param logNamePrefix
       *          log name prefix.
       * @return iterator of logs of the namespace.
       */
      CompletableFuture<Iterator<String>> getLogs(String logNamePrefix);
  
      /**
       * Register a namespace listener on streams changes.
       *
       * @param listener
       *          namespace listener
       */
      void registerNamespaceListener(NamespaceListener listener);
  }
  