Package org.apache.lucene.search.similarities

Class BasicStats

java.lang.Object
org.apache.lucene.search.similarities.Similarity.SimWeight
org.apache.lucene.search.similarities.BasicStats
Direct Known Subclasses:
LMSimilarity.LMStats
public class BasicStats extends Similarity.SimWeight
Stores all statistics commonly used ranking methods.

  • Field Details

    • numberOfDocuments

      protected long numberOfDocuments
      The number of documents.

    • numberOfFieldTokens

      protected long numberOfFieldTokens
      The total number of tokens in the field.

    • avgFieldLength

      protected float avgFieldLength
      The average field length.

    • docFreq

      protected long docFreq
      The document frequency.

    • totalTermFreq

      protected long totalTermFreq
      The total number of occurrences of this term across all documents.

    • queryBoost

      protected final float queryBoost
      Query's inner boost.

    • topLevelBoost

      protected float topLevelBoost
      Any outer query's boost.

    • totalBoost

      protected float totalBoost
      For most Similarities, the immediate and the top level query boosts are not handled differently. Hence, this field is just the product of the other two.

  • Constructor Details

    • BasicStats

      public BasicStats(String field, float queryBoost)
      Constructor. Sets the query boost.

  • Method Details

    • getNumberOfDocuments

      public long getNumberOfDocuments()
      Returns the number of documents.

    • setNumberOfDocuments

      public void setNumberOfDocuments(long numberOfDocuments)
      Sets the number of documents.

    • getNumberOfFieldTokens

      public long getNumberOfFieldTokens()
      Returns the total number of tokens in the field.
      See Also:

    • setNumberOfFieldTokens

      public void setNumberOfFieldTokens(long numberOfFieldTokens)
      Sets the total number of tokens in the field.
      See Also:

    • getAvgFieldLength

      public float getAvgFieldLength()
      Returns the average field length.

    • setAvgFieldLength

      public void setAvgFieldLength(float avgFieldLength)
      Sets the average field length.

    • getDocFreq

      public long getDocFreq()
      Returns the document frequency.

    • setDocFreq

      public void setDocFreq(long docFreq)
      Sets the document frequency.

    • getTotalTermFreq

      public long getTotalTermFreq()
      Returns the total number of occurrences of this term across all documents.

    • setTotalTermFreq

      public void setTotalTermFreq(long totalTermFreq)
      Sets the total number of occurrences of this term across all documents.

    • getValueForNormalization

      public float getValueForNormalization()
      The square of the raw normalization value.
      Specified by:
      getValueForNormalization in class Similarity.SimWeight
      See Also:

    • rawNormalizationValue

      protected float rawNormalizationValue()
      Computes the raw normalization value. This basic implementation returns the query boost. Subclasses may override this method to include other factors (such as idf), or to save the value for inclusion in normalize(float, float), etc.

    • normalize

      public void normalize(float queryNorm, float topLevelBoost)
      No normalization is done. topLevelBoost is saved in the object, however.
      Specified by:
      normalize in class Similarity.SimWeight

    • getTotalBoost

      public float getTotalBoost()
      Returns the total boost.