StringToIdMap.java example

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/**
 * Copyright (C) 2014-2016 LinkedIn Corp. (pinot-core@linkedin.com)
 *
 * Licensed 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.linkedin.pinot.core.query.aggregation.groupby.utils;

import it.unimi.dsi.fastutil.objects.Object2IntMap;
import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
import it.unimi.dsi.fastutil.objects.ObjectArrayList;
import it.unimi.dsi.fastutil.objects.ObjectList;


/**
 * Implementation of {@link ValueToIdMap} for String.
 */
public class StringToIdMap extends BaseValueToIdMap {
  Object2IntMap<String> _valueToIdMap;
  ObjectList<String> _idToValueMap;

  public StringToIdMap() {
    _valueToIdMap = new Object2IntOpenHashMap<>();
    _valueToIdMap.defaultReturnValue(INVALID_KEY);
    _idToValueMap = new ObjectArrayList<>();
  }

  @Override
  public int put(String value) {
    int id = _valueToIdMap.getInt(value);
    if (id == INVALID_KEY) {
      id = _idToValueMap.size();
      _valueToIdMap.put(value, id);
      _idToValueMap.add(value);
    }
    return id;
  }

  @Override
  public String getString(int id) {
    assert id < _idToValueMap.size();
    return _idToValueMap.get(id);
  }
}