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From cutt...@apache.org
Subject cvs commit: jakarta-lucene/src/java/org/apache/lucene/search QueryFilter.java
Date Mon, 05 Aug 2002 18:05:56 GMT
cutting     2002/08/05 11:05:56

  Modified:    .        CHANGES.txt
  Added:       src/java/org/apache/lucene/search QueryFilter.java
  Log:
  Added QueryFilter class.
  
  Revision  Changes    Path
  1.30      +13 -2     jakarta-lucene/CHANGES.txt
  
  Index: CHANGES.txt
  ===================================================================
  RCS file: /home/cvs/jakarta-lucene/CHANGES.txt,v
  retrieving revision 1.29
  retrieving revision 1.30
  diff -u -r1.29 -r1.30
  --- CHANGES.txt	5 Aug 2002 17:39:03 -0000	1.29
  +++ CHANGES.txt	5 Aug 2002 18:05:56 -0000	1.30
  @@ -71,7 +71,18 @@
        have been removed.
   
        Finally, repeating a token with an increment of zero can also be
  -     used to boost scores of matches on that token.
  +     used to boost scores of matches on that token.  (cutting)
  +
  + 14. Added new Filter class, QueryFilter.  This constrains search
  +     results to only match those which also match a provided query.
  +     Results are cached, so that searches after the first on the same
  +     index using this filter are very fast.
  +
  +     This could be used, for example, with a RangeQuery on a formatted
  +     date field to implement date filtering.  One could re-use a
  +     single QueryFilter that matches, e.g., only documents modified
  +     within the last week.  The QueryFilter and RangeQuery would only
  +     need to be reconstructed once per day. (cutting)
   
   
   1.2 RC6
  
  
  
  1.1                  jakarta-lucene/src/java/org/apache/lucene/search/QueryFilter.java
  
  Index: QueryFilter.java
  ===================================================================
  package org.apache.lucene.search;
  
  /* ====================================================================
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2001 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution,
   *    if any, must include the following acknowledgment:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowledgment may appear in the software itself,
   *    if and wherever such third-party acknowledgments normally appear.
   *
   * 4. The names "Apache" and "Apache Software Foundation" and
   *    "Apache Lucene" must not be used to endorse or promote products
   *    derived from this software without prior written permission. For
   *    written permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache",
   *    "Apache Lucene", nor may "Apache" appear in their name, without
   *    prior written permission of the Apache Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   */
  
  import java.io.IOException;
  import java.util.WeakHashMap;
  import java.util.BitSet;
  import org.apache.lucene.index.IndexReader;
  
  /** Constrains search results to only match those which also match a provided
   * query.  Results are cached, so that searches after the first on the same
   * index using this filter are much faster.
   *
   * <p> This could be used, for example, with a {@link RangeQuery} on a suitably
   * formatted date field to implement date filtering.  One could re-use a single
   * QueryFilter that matches, e.g., only documents modified within the last
   * week.  The QueryFilter and RangeQuery would only need to be reconstructed
   * once per day.
   */
  public class QueryFilter extends Filter {
    private Query query;
    private transient WeakHashMap cache = new WeakHashMap();
  
    /** Constructs a filter which only matches documents matching
     * <code>query</code>.
     */
    public QueryFilter(Query query) {
      this.query = query;
    }
  
    public BitSet bits(IndexReader reader) throws IOException {
  
      synchronized (cache) {                        // check cache
        BitSet cached = (BitSet)cache.get(reader);
        if (cached != null)
          return cached;
      }
  
      final BitSet bits = new BitSet(reader.maxDoc());
  
      new IndexSearcher(reader).search(query, new HitCollector() {
  	public final void collect(int doc, float score) {
            bits.set(doc);                          // set bit for hit
          }
        });
                                       
  
      synchronized (cache) {                        // update cache
        cache.put(reader, bits);
      }
  
      return bits;
    }
  }
  
  
  

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