pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/ReqOptSumScorer.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/ReqOptSumScorer.java
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/ReqOptSumScorer.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;
+
+/** A Scorer for queries with a required part and an optional part.
+ * Delays skipTo() on the optional part until a score() is needed.
+ * <br>
+ * This <code>Scorer</code> implements {@link Scorer#skipTo(int)}.
+ */
+class ReqOptSumScorer extends Scorer {
+  /** The scorers passed from the constructor.
+   * These are set to null as soon as their next() or skipTo() returns false.
+   */
+  private Scorer reqScorer;
+  private Scorer optScorer;
+
+  /** Construct a <code>ReqOptScorer</code>.
+   * @param reqScorer The required scorer. This must match.
+   * @param optScorer The optional scorer. This is used for scoring only.
+   */
+  public ReqOptSumScorer(
+      Scorer reqScorer,
+      Scorer optScorer)
+  {
+    super(reqScorer.weight);
+    this.reqScorer = reqScorer;
+    this.optScorer = optScorer;
+  }
+
+  @Override
+  public int nextDoc() throws IOException {
+    return reqScorer.nextDoc();
+  }
+  
+  @Override
+  public int advance(int target) throws IOException {
+    return reqScorer.advance(target);
+  }
+  
+  @Override
+  public int docID() {
+    return reqScorer.docID();
+  }
+  
+  /** Returns the score of the current document matching the query.
+   * Initially invalid, until {@link #nextDoc()} is called the first time.
+   * @return The score of the required scorer, eventually increased by the score
+   * of the optional scorer when it also matches the current document.
+   */
+  @Override
+  public float score() throws IOException {
+    int curDoc = reqScorer.docID();
+    float reqScore = reqScorer.score();
+    if (optScorer == null) {
+      return reqScore;
+    }
+    
+    int optScorerDoc = optScorer.docID();
+    if (optScorerDoc < curDoc && (optScorerDoc = optScorer.advance(curDoc)) == NO_MORE_DOCS) {
+      optScorer = null;
+      return reqScore;
+    }
+    
+    return optScorerDoc == curDoc ? reqScore + optScorer.score() : reqScore;
+  }
+
+}
+