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.arrow.vector.ipc.message;
  
  import com.google.flatbuffers.FlatBufferBuilder;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import org.apache.arrow.flatbuf.KeyValue;
  
  /** Utility methods for {@linkplain org.apache.arrow.vector.ipc.message.FBSerializable}s. */
  public class FBSerializables {
    private FBSerializables() {}
  
    /**
     * Writes every element of all to builder and calls {@link FlatBufferBuilder#endVector()}
     * afterwards. Returns the number of result of calling endVector.
     */
    public static int writeAllStructsToVector(
        FlatBufferBuilder builder, List<? extends FBSerializable> all) {
      // struct vectors have to be created in reverse order
      List<? extends FBSerializable> reversed = new ArrayList<>(all);
      Collections.reverse(reversed);
      for (FBSerializable element : reversed) {
        element.writeTo(builder);
      }
      return builder.endVector();
    }
  
    /** Writes map data with string type. */
    public static int writeKeyValues(FlatBufferBuilder builder, Map<String, String> metaData) {
      int[] metadataOffsets = new int[metaData.size()];
      Iterator<Map.Entry<String, String>> metadataIterator = metaData.entrySet().iterator();
      for (int i = 0; i < metadataOffsets.length; i++) {
        Map.Entry<String, String> kv = metadataIterator.next();
        int keyOffset = builder.createString(kv.getKey());
        int valueOffset = builder.createString(kv.getValue());
        KeyValue.startKeyValue(builder);
        KeyValue.addKey(builder, keyOffset);
        KeyValue.addValue(builder, valueOffset);
        metadataOffsets[i] = KeyValue.endKeyValue(builder);
      }
      return org.apache.arrow.flatbuf.Field.createCustomMetadataVector(builder, metadataOffsets);
    }
  }
  