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.asterix.runtime.evaluators.common;
  
  import java.io.DataInputStream;
  import java.nio.ByteBuffer;
  import java.util.Arrays;
  
  import org.apache.asterix.fuzzyjoin.similarity.SimilarityFilters;
  import org.apache.asterix.fuzzyjoin.similarity.SimilarityFiltersFactory;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.dataflow.common.comm.util.ByteBufferInputStream;
  import org.apache.hyracks.dataflow.common.data.marshalling.UTF8StringSerializerDeserializer;
  
  public class SimilarityFiltersCache {
      private final UTF8StringSerializerDeserializer utf8SerDer = new UTF8StringSerializerDeserializer();
  
      private final ByteBufferInputStream bbis = new ByteBufferInputStream();
      private final DataInputStream dis = new DataInputStream(bbis);
  
      private float similarityThresholdCached = 0;
      private byte[] similarityNameBytesCached = null;
      private SimilarityFilters similarityFiltersCached = null;
  
      public SimilarityFilters get(float similarityThreshold, byte[] similarityNameBytes, int startOffset, int len)
              throws HyracksDataException {
          if (similarityThreshold != similarityThresholdCached || similarityNameBytesCached == null
                  || !Arrays.equals(similarityNameBytes, similarityNameBytesCached)) {
              bbis.setByteBuffer(ByteBuffer.wrap(similarityNameBytes), startOffset + 1);
              String similarityName = utf8SerDer.deserialize(dis);
              similarityNameBytesCached = Arrays.copyOfRange(similarityNameBytes, startOffset, len);
              similarityFiltersCached =
                      SimilarityFiltersFactory.getSimilarityFilters(similarityName, similarityThreshold);
          }
          return similarityFiltersCached;
      }
  }
  