src/java/org/apache/lucene/search/HitCollector.java

package org.apache.lucene.search;

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/** Lower-level search API.
 * @see Searcher#search(Query,HitCollector)
 */
public abstract class HitCollector {
  /** Called once for every non-zero scoring document, with the document number
   * and its score.
   *
   * <P>If, for example, an application wished to collect all of the hits for a
   * query in a BitSet, then it might:<pre>
   *   Searcher = new IndexSearcher(indexReader);
   *   final BitSet bits = new BitSet(indexReader.maxDoc());
   *   searcher.search(query, new HitCollector() {
   *       public void collect(int doc, float score) {
   *         bits.set(doc);
   *       }
   *     });
   * </pre>
   *
   * <p>Note: This is called in an inner search loop.  For good search
   * performance, implementations of this method should not call {@link
   * Searcher#doc(int)} or {@link
   * org.apache.lucene.index.IndexReader#document(int)} on every document
   * number encountered.  Doing so can slow searches by an order of magnitude
   * or more. */
  public abstract void collect(int doc, float score);
}