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## org.apache.lucene.search
Interface Weight

All Superinterfaces:
  Serializable

public interface Weight
extends Serializable

Expert: Calculate query weights and build query scorers.

A Weight is constructed by a query, given a Searcher (`Query.createWeight(Searcher)`). The `sumOfSquaredWeights()` method is then called on the top-level query to compute the query normalization factor (@link Similarity#queryNorm(float)}). This factor is then passed to `normalize(float)`. At this point the weighting is complete and a scorer may be constructed by calling `scorer(IndexReader)`.

Method Summary
`Explanation` | `explain(IndexReader reader, int doc)` An explanation of the score computation for the named document.
`Query` | `getQuery()` The query that this concerns.
`float` | `getValue()` The weight for this query.
`void` | `normalize(float norm)` Assigns the query normalization factor to this.
`Scorer` | `scorer(IndexReader reader)` Constructs a scorer for this.
`float` | `sumOfSquaredWeights()` The sum of squared weights of contained query clauses.

Method Detail

### getQuery

    public Query getQuery()

  The query that this concerns.

### getValue

    public float getValue()

  The weight for this query.

### sumOfSquaredWeights

    public float sumOfSquaredWeights()
                              throws IOException

  The sum of squared weights of contained query clauses.

  Throws:
    `IOException`

### normalize

    public void normalize(float norm)

  Assigns the query normalization factor to this.

### scorer

    public Scorer scorer(IndexReader reader)
                  throws IOException

  Constructs a scorer for this.

  Throws:
    `IOException`

### explain

    public Explanation explain(IndexReader reader,
                               int doc)
                        throws IOException

  An explanation of the score computation for the named document.

  Throws:
    `IOException`

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