pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / search / QueryWrapperFilter.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/QueryWrapperFilter.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/QueryWrapperFilter.java
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/QueryWrapperFilter.java
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+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.index.IndexReader;
+
+/** 
+ * Constrains search results to only match those which also match a provided
+ * query.  
+ *
+ * <p> This could be used, for example, with a {@link TermRangeQuery} 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 TermRangeQuery would only need to be reconstructed
+ * once per day.
+ */
+public class QueryWrapperFilter extends Filter {
+  private Query query;
+
+  /** Constructs a filter which only matches documents matching
+   * <code>query</code>.
+   */
+  public QueryWrapperFilter(Query query) {
+    this.query = query;
+  }
+
+  @Override
+  public DocIdSet getDocIdSet(final IndexReader reader) throws IOException {
+    final Weight weight = new IndexSearcher(reader).createNormalizedWeight(query);
+    return new DocIdSet() {
+      @Override
+      public DocIdSetIterator iterator() throws IOException {
+        return weight.scorer(reader, true, false);
+      }
+      @Override
+      public boolean isCacheable() { return false; }
+    };
+  }
+
+  @Override
+  public String toString() {
+    return "QueryWrapperFilter(" + query + ")";
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (!(o instanceof QueryWrapperFilter))
+      return false;
+    return this.query.equals(((QueryWrapperFilter)o).query);
+  }
+
+  @Override
+  public int hashCode() {
+    return query.hashCode() ^ 0x923F64B9;
+  }
+}