pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/MultiTermQueryWrapperFilter.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/MultiTermQueryWrapperFilter.java
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/MultiTermQueryWrapperFilter.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;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.index.TermDocs;
+import org.apache.lucene.index.TermEnum;
+import org.apache.lucene.util.FixedBitSet;
+
+/**
+ * A wrapper for {@link MultiTermQuery}, that exposes its
+ * functionality as a {@link Filter}.
+ * <P>
+ * <code>MultiTermQueryWrapperFilter</code> is not designed to
+ * be used by itself. Normally you subclass it to provide a Filter
+ * counterpart for a {@link MultiTermQuery} subclass.
+ * <P>
+ * For example, {@link TermRangeFilter} and {@link PrefixFilter} extend
+ * <code>MultiTermQueryWrapperFilter</code>.
+ * This class also provides the functionality behind
+ * {@link MultiTermQuery#CONSTANT_SCORE_FILTER_REWRITE};
+ * this is why it is not abstract.
+ */
+public class MultiTermQueryWrapperFilter<Q extends MultiTermQuery> extends Filter {
+    
+  protected final Q query;
+
+  /**
+   * Wrap a {@link MultiTermQuery} as a Filter.
+   */
+  protected MultiTermQueryWrapperFilter(Q query) {
+      this.query = query;
+  }
+  
+  @Override
+  public String toString() {
+    // query.toString should be ok for the filter, too, if the query boost is 1.0f
+    return query.toString();
+  }
+
+  @Override
+  public final boolean equals(final Object o) {
+    if (o==this) return true;
+    if (o==null) return false;
+    if (this.getClass().equals(o.getClass())) {
+      return this.query.equals( ((MultiTermQueryWrapperFilter)o).query );
+    }
+    return false;
+  }
+
+  @Override
+  public final int hashCode() {
+    return query.hashCode();
+  }
+  
+  /**
+   * Expert: Return the number of unique terms visited during execution of the filter.
+   * If there are many of them, you may consider using another filter type
+   * or optimize your total term count in index.
+   * <p>This method is not thread safe, be sure to only call it when no filter is running!
+   * If you re-use the same filter instance for another
+   * search, be sure to first reset the term counter
+   * with {@link #clearTotalNumberOfTerms}.
+   * @see #clearTotalNumberOfTerms
+   * @deprecated Don't use this method, as its not thread safe and useless.
+   */
+  @Deprecated
+  public int getTotalNumberOfTerms() {
+    return query.getTotalNumberOfTerms();
+  }
+  
+  /**
+   * Expert: Resets the counting of unique terms.
+   * Do this before executing the filter.
+   * @see #getTotalNumberOfTerms
+   * @deprecated Don't use this method, as its not thread safe and useless.
+   */
+  @Deprecated
+  public void clearTotalNumberOfTerms() {
+    query.clearTotalNumberOfTerms();
+  }
+  
+  /**
+   * Returns a DocIdSet with documents that should be
+   * permitted in search results.
+   */
+  @Override
+  public DocIdSet getDocIdSet(IndexReader reader) throws IOException {
+    final TermEnum enumerator = query.getEnum(reader);
+    try {
+      // if current term in enum is null, the enum is empty -> shortcut
+      if (enumerator.term() == null)
+        return DocIdSet.EMPTY_DOCIDSET;
+      // else fill into a FixedBitSet
+      final FixedBitSet bitSet = new FixedBitSet(reader.maxDoc());
+      final int[] docs = new int[32];
+      final int[] freqs = new int[32];
+      TermDocs termDocs = reader.termDocs();
+      try {
+        int termCount = 0;
+        do {
+          Term term = enumerator.term();
+          if (term == null)
+            break;
+          termCount++;
+          termDocs.seek(term);
+          while (true) {
+            final int count = termDocs.read(docs, freqs);
+            if (count != 0) {
+              for(int i=0;i<count;i++) {
+                bitSet.set(docs[i]);
+              }
+            } else {
+              break;
+            }
+          }
+        } while (enumerator.next());
+
+        query.incTotalNumberOfTerms(termCount);
+
+      } finally {
+        termDocs.close();
+      }
+      return bitSet;
+    } finally {
+      enumerator.close();
+    }
+  }
+
+}