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.carbondata.core.localdictionary.generator;
  
  import java.nio.ByteBuffer;
  
  import org.apache.carbondata.core.constants.CarbonCommonConstants;
  import org.apache.carbondata.core.localdictionary.dictionaryholder.DictionaryStore;
  import org.apache.carbondata.core.localdictionary.dictionaryholder.MapBasedDictionaryStore;
  import org.apache.carbondata.core.localdictionary.exception.DictionaryThresholdReachedException;
  
  /**
   * Class to generate local dictionary for column
   */
  public class ColumnLocalDictionaryGenerator implements LocalDictionaryGenerator {
  
    /**
     * dictionary holder to hold dictionary values
     */
    private DictionaryStore dictionaryHolder;
  
    /**
     * number of bytes used for storing the length of the dictionary value
     */
    private int lvLength;
  
    public ColumnLocalDictionaryGenerator(int threshold, int lvLength) {
      // adding 1 to threshold for null value
      int newThreshold = threshold + 1;
      this.dictionaryHolder = new MapBasedDictionaryStore(newThreshold);
      this.lvLength = lvLength;
      ByteBuffer byteBuffer = ByteBuffer.allocate(
          lvLength + CarbonCommonConstants.MEMBER_DEFAULT_VAL_ARRAY.length);
  
      if (lvLength == CarbonCommonConstants.SHORT_SIZE_IN_BYTE) {
        byteBuffer.putShort((short) CarbonCommonConstants.MEMBER_DEFAULT_VAL_ARRAY.length);
      } else {
        byteBuffer.putInt(CarbonCommonConstants.MEMBER_DEFAULT_VAL_ARRAY.length);
      }
      byteBuffer.put(CarbonCommonConstants.MEMBER_DEFAULT_VAL_ARRAY);
      // for handling null values
      try {
        dictionaryHolder.putIfAbsent(byteBuffer.array());
      } catch (DictionaryThresholdReachedException e) {
        // do nothing
      }
    }
  
    /**
     * Below method will be used to generate dictionary
     * @param data
     * data for which dictionary needs to be generated
     * @return dictionary value
     */
    @Override
    public int generateDictionary(byte[] data) throws DictionaryThresholdReachedException {
      return this.dictionaryHolder.putIfAbsent(data);
    }
  
    /**
     * Below method will be used to check if threshold is reached
     * for dictionary for particular column
     * @return true if dictionary threshold reached for column
     */
    @Override
    public boolean isThresholdReached() {
      return this.dictionaryHolder.isThresholdReached();
    }
  
    /**
     * Below method will be used to get the dictionary key based on value
     * @param value
     * dictionary value
     * @return dictionary key based on value
     */
    @Override
    public byte[] getDictionaryKeyBasedOnValue(int value) {
      return this.dictionaryHolder.getDictionaryKeyBasedOnValue(value);
    }
  
    @Override
    public int getLVLength() {
      return this.lvLength;
    }
  }
  