content: package org.apache.lucene.search;
  
  /**
   * 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.
   */
  
  import java.io.IOException;
  
  import org.apache.lucene.document.Document;
  import org.apache.lucene.index.CorruptIndexException;
  import org.apache.lucene.index.Term;
  import org.apache.lucene.search.IndexSearcher.MdrillCollector;
  import org.apache.lucene.document.FieldSelector;
  
  /**
   * An abstract base class for search implementations. Implements the main search
   * methods.
   * 
   * <p>
   * Note that you can only access hits from a Searcher as long as it is not yet
   * closed, otherwise an IOException will be thrown.
   *
   * @deprecated In 4.0 this abstract class is removed/absorbed
   * into IndexSearcher
   */
  @Deprecated
  public abstract class Searcher implements Searchable {
    /** Search implementation with arbitrary sorting.  Finds
     * the top <code>n</code> hits for <code>query</code>, applying
     * <code>filter</code> if non-null, and sorting the hits by the criteria in
     * <code>sort</code>.
     * 
     * <p>NOTE: this does not compute scores by default; use
     * {@link IndexSearcher#setDefaultFieldSortScoring} to
     * enable scoring.
     *
     * @throws BooleanQuery.TooManyClauses
     */
    public TopFieldDocs search(Query query, Filter filter, int n,
                               Sort sort) throws IOException {
      return search(createNormalizedWeight(query), filter, n, sort);
    }
  
    /**
     * Search implementation with arbitrary sorting and no filter.
     * @param query The query to search for
     * @param n Return only the top n results
     * @param sort The {@link org.apache.lucene.search.Sort} object
     * @return The top docs, sorted according to the supplied {@link org.apache.lucene.search.Sort} instance
     * @throws IOException
     */
    public TopFieldDocs search(Query query, int n,
                               Sort sort) throws IOException {
      return search(createNormalizedWeight(query), null, n, sort);
    }
  
    /** Lower-level search API.
    *
    * <p>{@link Collector#collect(int)} is called for every matching document.
    *
    * <p>Applications should only use this if they need <i>all</i> of the
    * matching documents.  The high-level search API ({@link
    * Searcher#search(Query, int)}) is usually more efficient, as it skips
    * non-high-scoring hits.
    * <p>Note: The <code>score</code> passed to this method is a raw score.
    * In other words, the score will not necessarily be a float whose value is
    * between 0 and 1.
    * @throws BooleanQuery.TooManyClauses
    */
   public void search(Query query, Collector results)
     throws IOException {
     search(createNormalizedWeight(query), null, results);
   }
  
    /** Lower-level search API.
     *
     * <p>{@link Collector#collect(int)} is called for every matching
     * document.
     * <br>Collector-based access to remote indexes is discouraged.
     *
     * <p>Applications should only use this if they need <i>all</i> of the
     * matching documents.  The high-level search API ({@link
     * Searcher#search(Query, Filter, int)}) is usually more efficient, as it skips
     * non-high-scoring hits.
     *
     * @param query to match documents
     * @param filter if non-null, used to permit documents to be collected.
     * @param results to receive hits
     * @throws BooleanQuery.TooManyClauses
     */
    public void search(Query query, Filter filter, Collector results)
    throws IOException {
      search(createNormalizedWeight(query), filter, results);
    }
  
    /** Finds the top <code>n</code>
     * hits for <code>query</code>, applying <code>filter</code> if non-null.
     *
     * @throws BooleanQuery.TooManyClauses
     */
    public TopDocs search(Query query, Filter filter, int n)
      throws IOException {
      return search(createNormalizedWeight(query), filter, n);
    }
  
    /** Finds the top <code>n</code>
     * hits for <code>query</code>.
     *
     * @throws BooleanQuery.TooManyClauses
     */
    public TopDocs search(Query query, int n)
      throws IOException {
      return search(query, null, n);
    }
  
    /** Returns an Explanation that describes how <code>doc</code> scored against
     * <code>query</code>.
     *
     * <p>This is intended to be used in developing Similarity implementations,
     * and, for good performance, should not be displayed with every hit.
     * Computing an explanation is as expensive as executing the query over the
     * entire index.
     */
    public Explanation explain(Query query, int doc) throws IOException {
      return explain(createNormalizedWeight(query), doc);
    }
  
    /** The Similarity implementation used by this searcher. */
    private Similarity similarity = Similarity.getDefault();
  
    /** Expert: Set the Similarity implementation used by this Searcher.
     *
     * @see Similarity#setDefault(Similarity)
     */
    public void setSimilarity(Similarity similarity) {
      this.similarity = similarity;
    }
  
    /** Expert: Return the Similarity implementation used by this Searcher.
     *
     * <p>This defaults to the current value of {@link Similarity#getDefault()}.
     */
    public Similarity getSimilarity() {
      return this.similarity;
    }
  
    /**
     * Creates a normalized weight for a top-level {@link Query}.
     * The query is rewritten by this method and {@link Query#createWeight} called,
     * afterwards the {@link Weight} is normalized. The returned {@code Weight}
     * can then directly be used to get a {@link Scorer}.
     * @lucene.internal
     */
    public Weight createNormalizedWeight(Query query) throws IOException {
      query = rewrite(query);
      Weight weight = query.createWeight(this);
      float sum = weight.sumOfSquaredWeights();
      // this is a hack for backwards compatibility:
      float norm = query.getSimilarity(this).queryNorm(sum);
      if (Float.isInfinite(norm) || Float.isNaN(norm))
        norm = 1.0f;
      weight.normalize(norm);
      return weight;
    }
    
    /**
     * Expert: Creates a normalized weight for a top-level {@link Query}.
     * The query is rewritten by this method and {@link Query#createWeight} called,
     * afterwards the {@link Weight} is normalized. The returned {@code Weight}
     * can then directly be used to get a {@link Scorer}.
     * @deprecated never ever use this method in {@link Weight} implementations.
     * Subclasses of Searcher should use {@link #createNormalizedWeight}, instead.
     */
    @Deprecated
    protected final Weight createWeight(Query query) throws IOException {
      return createNormalizedWeight(query);
    }
  
    // inherit javadoc
    public int[] docFreqs(Term[] terms) throws IOException {
      int[] result = new int[terms.length];
      for (int i = 0; i < terms.length; i++) {
        result[i] = docFreq(terms[i]);
      }
      return result;
    }
  
    abstract public void search(Weight weight, Filter filter, Collector results) throws IOException;
    abstract public void close() throws IOException;
    abstract public int docFreq(Term term) throws IOException;
    abstract public int maxDoc() throws IOException;
    abstract public TopDocs search(Weight weight, Filter filter, int n) throws IOException;
    abstract public Document doc(int i) throws CorruptIndexException, IOException;
    abstract public Document doc(int docid, FieldSelector fieldSelector) throws CorruptIndexException, IOException;
    abstract public Query rewrite(Query query) throws IOException;
    abstract public Explanation explain(Weight weight, int doc) throws IOException;
    abstract public TopFieldDocs search(Weight weight, Filter filter, int n, Sort sort) throws IOException;
    /* End patch for GCJ bug #15411. */
    public void ScoreFind(Query query, Filter filter, MdrillCollector results)
    throws IOException{
  	  ScoreFind(createNormalizedWeight(query), filter, results);
    }
    abstract public void ScoreFind(Weight weight, Filter filter, MdrillCollector collector)
    throws IOException;
  }
  