pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/SpanQueryFilter.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/SpanQueryFilter.java
new file mode 100644 (file)
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+package org.apache.lucene.search;
+/**
+ * Copyright 2007 The Apache Software Foundation
+ *
+ * Licensed 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 org.apache.lucene.index.IndexReader;
+import org.apache.lucene.search.spans.SpanQuery;
+import org.apache.lucene.search.spans.Spans;
+import org.apache.lucene.util.FixedBitSet;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Constrains search results to only match those which also match a provided
+ * query. Also provides position information about where each document matches
+ * at the cost of extra space compared with the QueryWrapperFilter.
+ * There is an added cost to this above what is stored in a {@link QueryWrapperFilter}.  Namely,
+ * the position information for each matching document is stored.
+ * <p/>
+ * This filter does not cache.  See the {@link org.apache.lucene.search.CachingSpanFilter} for a wrapper that
+ * caches.
+ */
+public class SpanQueryFilter extends SpanFilter {
+  protected SpanQuery query;
+
+  protected SpanQueryFilter()
+  {
+    
+  }
+
+  /** Constructs a filter which only matches documents matching
+   * <code>query</code>.
+   * @param query The {@link org.apache.lucene.search.spans.SpanQuery} to use as the basis for the Filter.
+   */
+  public SpanQueryFilter(SpanQuery query) {
+    this.query = query;
+  }
+
+  @Override
+  public DocIdSet getDocIdSet(IndexReader reader) throws IOException {
+    SpanFilterResult result = bitSpans(reader);
+    return result.getDocIdSet();
+  }
+
+  @Override
+  public SpanFilterResult bitSpans(IndexReader reader) throws IOException {
+
+    final FixedBitSet bits = new FixedBitSet(reader.maxDoc());
+    Spans spans = query.getSpans(reader);
+    List<SpanFilterResult.PositionInfo> tmp = new ArrayList<SpanFilterResult.PositionInfo>(20);
+    int currentDoc = -1;
+    SpanFilterResult.PositionInfo currentInfo = null;
+    while (spans.next())
+    {
+      int doc = spans.doc();
+      bits.set(doc);
+      if (currentDoc != doc)
+      {
+        currentInfo = new SpanFilterResult.PositionInfo(doc);
+        tmp.add(currentInfo);
+        currentDoc = doc;
+      }
+      currentInfo.addPosition(spans.start(), spans.end());
+    }
+    return new SpanFilterResult(bits, tmp);
+  }
+
+
+  public SpanQuery getQuery() {
+    return query;
+  }
+
+  @Override
+  public String toString() {
+    return "SpanQueryFilter(" + query + ")";
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    return o instanceof SpanQueryFilter && this.query.equals(((SpanQueryFilter) o).query);
+  }
+
+  @Override
+  public int hashCode() {
+    return query.hashCode() ^ 0x923F64B9;
+  }
+}