/*
 * 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.parquet.variant;

import java.nio.ByteBuffer;
import java.util.HashMap;

/**
 * Metadata that is set up at construction time, and never modified.
 */
public class ImmutableMetadata implements Metadata {
  private final HashMap<String, Integer> dictionary;
  private final ByteBuffer metadataBuffer;

  public ImmutableMetadata(ByteBuffer metadata) {
    this.dictionary = VariantUtil.getMetadataMap(metadata);
    this.metadataBuffer = metadata;
  }

  @Override
  public int getOrInsert(String key) {
    Integer result = dictionary.get(key);
    if (result == null) {
      throw new IllegalArgumentException("Key does not exist in metadata: " + key);
    }
    return result;
  }

  @Override
  public ByteBuffer getEncodedBuffer() {
    return metadataBuffer;
  }
}
