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 com.datastax.oss.driver.internal.core.adminrequest;
  
  import com.datastax.oss.driver.api.core.ProtocolVersion;
  import com.datastax.oss.driver.internal.core.util.concurrent.CompletableFutures;
  import com.datastax.oss.driver.shaded.guava.common.collect.AbstractIterator;
  import com.datastax.oss.driver.shaded.guava.common.collect.ImmutableMap;
  import com.datastax.oss.protocol.internal.response.result.ColumnSpec;
  import com.datastax.oss.protocol.internal.response.result.Rows;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import java.nio.ByteBuffer;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Queue;
  import java.util.concurrent.CompletionStage;
  import net.jcip.annotations.NotThreadSafe;
  
  @NotThreadSafe // wraps a mutable queue
  public class AdminResult implements Iterable<AdminRow> {
  
    private final Queue<List<ByteBuffer>> data;
    private final Map<String, ColumnSpec> columnSpecs;
    private final AdminRequestHandler<AdminResult> nextHandler;
    private final ProtocolVersion protocolVersion;
  
    public AdminResult(
        Rows rows, AdminRequestHandler<AdminResult> nextHandler, ProtocolVersion protocolVersion) {
      this.data = rows.getData();
  
      ImmutableMap.Builder<String, ColumnSpec> columnSpecsBuilder = ImmutableMap.builder();
      for (ColumnSpec spec : rows.getMetadata().columnSpecs) {
        columnSpecsBuilder.put(spec.name, spec);
      }
      // Admin queries are simple selects only, so there are no duplicate names (if that ever
      // changes, build() will fail and we'll have to do things differently)
      this.columnSpecs = columnSpecsBuilder.build();
  
      this.nextHandler = nextHandler;
      this.protocolVersion = protocolVersion;
    }
  
    /** This consumes the result's data and can be called only once. */
    @NonNull
    @Override
    public Iterator<AdminRow> iterator() {
      return new AbstractIterator<AdminRow>() {
        @Override
        protected AdminRow computeNext() {
          List<ByteBuffer> rowData = data.poll();
          return (rowData == null)
              ? endOfData()
              : new AdminRow(columnSpecs, rowData, protocolVersion);
        }
      };
    }
  
    public boolean hasNextPage() {
      return nextHandler != null;
    }
  
    public CompletionStage<AdminResult> nextPage() {
      return (nextHandler == null)
          ? CompletableFutures.failedFuture(
              new AssertionError("No next page, use hasNextPage() before you call this method"))
          : nextHandler.start();
    }
  }
  