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.bookkeeper.api.kv;
  
  import static io.netty.util.ReferenceCountUtil.retain;
  
  import java.util.concurrent.CompletableFuture;
  import org.apache.bookkeeper.api.kv.exceptions.KvApiException;
  import org.apache.bookkeeper.api.kv.options.Options;
  import org.apache.bookkeeper.api.kv.options.RangeOption;
  import org.apache.bookkeeper.api.kv.result.Code;
  import org.apache.bookkeeper.api.kv.result.KeyValue;
  import org.apache.bookkeeper.api.kv.result.RangeResult;
  import org.apache.bookkeeper.common.annotation.InterfaceAudience;
  import org.apache.bookkeeper.common.annotation.InterfaceStability;
  import org.apache.bookkeeper.common.concurrent.FutureUtils;
  
  /**
   * A review view of a key/value space.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Evolving
  public interface TableReadView<K, V> extends PTableBase<K, V> {
  
      CompletableFuture<RangeResult<K, V>> get(K key, RangeOption<K> option);
  
      default CompletableFuture<Long> getNumber(K key) {
          RangeOption<K> option = opFactory().optionFactory().newRangeOption().build();
          return get(key, option)
              .thenCompose(result -> {
                  try {
                      if (result.count() == 0) {
                          return FutureUtils.value(null);
                      } else {
                          KeyValue<K, V> kv = result.kvs().get(0);
                          if (kv.isNumber()) {
                              return FutureUtils.value(kv.numberValue());
                          } else {
                              return FutureUtils.exception(new KvApiException(
                                  Code.ILLEGAL_OP, "Key (" + key + ") doesn't have any number value"));
                          }
                      }
                  } finally {
                      result.close();
                  }
              })
              .whenComplete((value, cause) -> option.close());
      }
  
      default CompletableFuture<V> get(K key) {
          RangeOption<K> option = opFactory().optionFactory().newRangeOption().build();
          return get(key, option)
              .thenApply(result -> {
                  try {
                      if (result.count() == 0) {
                          return null;
                      } else {
                          return retain(result.kvs().get(0).value());
                      }
                  } finally {
                      result.close();
                  }
              })
              .whenComplete((value, cause) -> option.close());
  
      }
  
      default CompletableFuture<KeyValue<K, V>> getKv(K key) {
          return get(key, Options.get())
              .thenApply(result -> {
                  try {
                      if (result.count() == 0) {
                          return null;
                      } else {
                          return result.getKvsAndClear().get(0);
                      }
                  } finally {
                      result.close();
                  }
              });
      }
  
  }
  