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.fuzzyjoin.similarity;
  
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.data.std.util.ISequenceIterator;
  
  public abstract class SimilarityMetric {
  
      public static int getIntersectSize(ISequenceIterator tokensX, ISequenceIterator tokensY)
              throws HyracksDataException {
          int intersectSize = 0;
          while (tokensX.hasNext() && tokensY.hasNext()) {
              int cmp = tokensX.compare(tokensY);
              if (cmp > 0) {
                  tokensY.next();
              } else if (cmp < 0) {
                  tokensX.next();
              } else {
                  intersectSize++;
                  tokensX.next();
                  tokensY.next();
              }
          }
          return intersectSize;
      }
  
      public static int getIntersectSize(int[] tokensX, int startX, int lengthX, int[] tokensY, int startY, int lengthY) {
          int posX = 0;
          int posY = 0;
          int intersectSize = 0;
  
          while (posX < lengthX && posY < lengthY) {
              int tokenX = tokensX[startX + posX];
              int tokenY = tokensY[startY + posY];
              if (tokenX > tokenY) {
                  posY++;
              } else if (tokenX < tokenY) {
                  posX++;
              } else {
                  intersectSize++;
                  posX++;
                  posY++;
              }
          }
  
          return intersectSize;
      }
  
      public static int getIntersectSize(int[] tokensX, int startX, int[] tokensY, int startY) {
          return getIntersectSize(tokensX, startX, tokensX.length, tokensY, startY, tokensY.length);
      }
  
      public static int getIntersectSize(int[] tokensX, int[] tokensY) {
          return getIntersectSize(tokensX, 0, tokensX.length, tokensY, 0, tokensY.length);
      }
  
      public static PartialIntersect getPartialIntersectSize(int[] tokensX, int startX, int lengthX, int[] tokensY,
              int startY, int lengthY, int tokenStop) {
          PartialIntersect parInter = new PartialIntersect();
          getPartialIntersectSize(tokensX, startX, lengthX, tokensY, startY, lengthY, tokenStop, parInter);
          return parInter;
      }
  
      public static void getPartialIntersectSize(int[] tokensX, int startX, int lengthX, int[] tokensY, int startY,
              int lengthY, int tokenStop, PartialIntersect parInter) {
          int posX = 0;
          int posY = 0;
          int intersectSize = 0;
  
          parInter.reset();
          while (posX < lengthX && posY < lengthY) {
              int tokenX = tokensX[startX + posX];
              int tokenY = tokensY[startY + posY];
              if (tokenX > tokenY) {
                  posY++;
              } else if (tokenX < tokenY) {
                  posX++;
              } else {
                  intersectSize++;
                  if (!parInter.isSet()) {
                      parInter.posXStart = posX;
                      parInter.posYStart = posY;
                      parInter.set();
                  }
                  if (tokenX == tokenStop) {
                      parInter.posXStop = posX;
                      parInter.posYStop = posY;
                      parInter.intersectSize = intersectSize;
                  }
                  posX++;
                  posY++;
              }
          }
      }
  
      public static PartialIntersect getPartialIntersectSize(int[] tokensX, int[] tokensY, int tokenStop) {
          return getPartialIntersectSize(tokensX, 0, tokensX.length, tokensY, 0, tokensY.length, tokenStop);
      }
  
      public abstract float getSimilarity(int[] tokensX, int startX, int lengthX, int[] tokensY, int startY, int lengthY);
  
  }
  