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.stream.cli.commands.table;
  
  import static com.google.common.base.Preconditions.checkArgument;
  import static java.nio.charset.StandardCharsets.UTF_8;
  import static org.apache.bookkeeper.common.concurrent.FutureUtils.result;
  import static org.apache.bookkeeper.stream.cli.Commands.OP_GET;
  
  import com.beust.jcommander.Parameter;
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufUtil;
  import io.netty.buffer.Unpooled;
  import org.apache.bookkeeper.api.StorageClient;
  import org.apache.bookkeeper.api.kv.Table;
  import org.apache.bookkeeper.api.kv.result.KeyValue;
  import org.apache.bookkeeper.stream.cli.commands.ClientCommand;
  import org.apache.bookkeeper.stream.cli.commands.table.GetCommand.Flags;
  import org.apache.bookkeeper.tools.framework.CliFlags;
  import org.apache.bookkeeper.tools.framework.CliSpec;
  
  /**
   * Command to get kv.
   */
  public class GetCommand extends ClientCommand<Flags> {
  
      private static final String NAME = OP_GET;
      private static final String DESC = "Get key/value pair from a table";
  
      /**
       * Flags for the get kv command.
       */
      public static class Flags extends CliFlags {
  
          @Parameter(names = { "-w", "--watch" }, description = "watch the value changes of a key")
          private boolean watch = false;
  
      }
  
      public GetCommand() {
          super(CliSpec.<Flags>newBuilder()
              .withName(NAME)
              .withDescription(DESC)
              .withFlags(new Flags())
              .withArgumentsUsage("<table> <key>")
              .build());
      }
  
      @Override
      @SuppressFBWarnings("RCN_REDUNDANT_NULLCHECK_WOULD_HAVE_BEEN_A_NPE")
      protected void run(StorageClient client, Flags flags) throws Exception {
          checkArgument(flags.arguments.size() >= 2,
              "table and key are not provided");
  
          String tableName = flags.arguments.get(0);
          String key = flags.arguments.get(1);
  
          try (Table<ByteBuf, ByteBuf> table = result(client.openTable(tableName))) {
              long lastVersion = -1L;
              do {
                  try (KeyValue<ByteBuf, ByteBuf> kv =
                           result(table.getKv(Unpooled.wrappedBuffer(key.getBytes(UTF_8))))) {
                      if (null == kv) {
                          spec.console().println("key '" + key + "' doesn't exist.");
                      } else {
                          if (kv.version() > lastVersion) {
                              if (kv.isNumber()) {
                                  spec.console().println("value = " + kv.numberValue());
                              } else {
                                  spec.console()
                                      .println("value = " + new String(ByteBufUtil.getBytes(kv.value()), UTF_8));
                              }
                              lastVersion = kv.version();
                          }
                      }
                  }
                  if (flags.watch) {
                      Thread.sleep(1000);
                  }
              } while (flags.watch);
          }
      }
  
  }
  