QrySopScore.java

/**
 *  Copyright (c) 2016, Carnegie Mellon University.  All Rights Reserved.
 */

import java.io.*;
import java.lang.IllegalArgumentException;

/**
 *  The SCORE operator for all retrieval models.
 */
public class QrySopScore extends QrySop {

  /**
   *  Document-independent values that should be determined just once.
   *  Some retrieval models have these, some don't.
   */
  
  /**
   *  Indicates whether the query has a match.
   *  @param r The retrieval model that determines what is a match
   *  @return True if the query matches, otherwise false.
   */
  public boolean docIteratorHasMatch (RetrievalModel r) {
    return this.docIteratorHasMatchFirst (r);
  }

  /**
   *  Get a score for the document that docIteratorHasMatch matched.
   *  @param r The retrieval model that determines how scores are calculated.
   *  @return The document score.
   *  @throws IOException Error accessing the Lucene index
   */
  public double getScore (RetrievalModel r) throws IOException {

    if (r instanceof RetrievalModelUnrankedBoolean) {
      return this.getScoreUnrankedBoolean (r);
    } else {
      throw new IllegalArgumentException
        (r.getClass().getName() + " doesn't support the SCORE operator.");
    }
  }
  
  /**
   *  getScore for the Unranked retrieval model.
   *  @param r The retrieval model that determines how scores are calculated.
   *  @return The document score.
   *  @throws IOException Error accessing the Lucene index
   */
  public double getScoreUnrankedBoolean (RetrievalModel r) throws IOException {
    if (! this.docIteratorHasMatchCache()) {
      return 0.0;
    } else {
      return 1.0;
    }
  }

  /**
   *  Initialize the query operator (and its arguments), including any
   *  internal iterators.  If the query operator is of type QryIop, it
   *  is fully evaluated, and the results are stored in an internal
   *  inverted list that may be accessed via the internal iterator.
   *  @param r A retrieval model that guides initialization
   *  @throws IOException Error accessing the Lucene index.
   */
  public void initialize (RetrievalModel r) throws IOException {

    Qry q = this.args.get (0);
    q.initialize (r);
  }

}