X-Git-Url: https://git.mdrn.pl/pylucene.git/blobdiff_plain/a2e61f0c04805cfcb8706176758d1283c7e3a55c..aaeed5504b982cf3545252ab528713250aa33eed:/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/ConjunctionScorer.java?ds=sidebyside

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/ConjunctionScorer.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/ConjunctionScorer.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 org.apache.lucene.util.ArrayUtil;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Comparator;
+
+/** Scorer for conjunctions, sets of queries, all of which are required. */
+class ConjunctionScorer extends Scorer {
+  
+  private final Scorer[] scorers;
+  private final float coord;
+  private int lastDoc = -1;
+
+  public ConjunctionScorer(Weight weight, float coord, Collection<Scorer> scorers) throws IOException {
+    this(weight, coord, scorers.toArray(new Scorer[scorers.size()]));
+  }
+
+  public ConjunctionScorer(Weight weight, float coord, Scorer... scorers) throws IOException {
+    super(weight);
+    this.scorers = scorers;
+    this.coord = coord;
+    
+    for (int i = 0; i < scorers.length; i++) {
+      if (scorers[i].nextDoc() == NO_MORE_DOCS) {
+        // If even one of the sub-scorers does not have any documents, this
+        // scorer should not attempt to do any more work.
+        lastDoc = NO_MORE_DOCS;
+        return;
+      }
+    }
+
+    // Sort the array the first time...
+    // We don't need to sort the array in any future calls because we know
+    // it will already start off sorted (all scorers on same doc).
+    
+    // Note that this comparator is not consistent with equals!
+    // Also we use mergeSort here to be stable (so order of Scoreres that
+    // match on first document keeps preserved):
+    ArrayUtil.mergeSort(scorers, new Comparator<Scorer>() { // sort the array
+      public int compare(Scorer o1, Scorer o2) {
+        return o1.docID() - o2.docID();
+      }
+    });
+
+    // NOTE: doNext() must be called before the re-sorting of the array later on.
+    // The reason is this: assume there are 5 scorers, whose first docs are 1,
+    // 2, 3, 5, 5 respectively. Sorting (above) leaves the array as is. Calling
+    // doNext() here advances all the first scorers to 5 (or a larger doc ID
+    // they all agree on). 
+    // However, if we re-sort before doNext() is called, the order will be 5, 3,
+    // 2, 1, 5 and then doNext() will stop immediately, since the first scorer's
+    // docs equals the last one. So the invariant that after calling doNext() 
+    // all scorers are on the same doc ID is broken.
+    if (doNext() == NO_MORE_DOCS) {
+      // The scorers did not agree on any document.
+      lastDoc = NO_MORE_DOCS;
+      return;
+    }
+
+    // If first-time skip distance is any predictor of
+    // scorer sparseness, then we should always try to skip first on
+    // those scorers.
+    // Keep last scorer in it's last place (it will be the first
+    // to be skipped on), but reverse all of the others so that
+    // they will be skipped on in order of original high skip.
+    int end = scorers.length - 1;
+    int max = end >> 1;
+    for (int i = 0; i < max; i++) {
+      Scorer tmp = scorers[i];
+      int idx = end - i - 1;
+      scorers[i] = scorers[idx];
+      scorers[idx] = tmp;
+    }
+  }
+
+  private int doNext() throws IOException {
+    int first = 0;
+    int doc = scorers[scorers.length - 1].docID();
+    Scorer firstScorer;
+    while ((firstScorer = scorers[first]).docID() < doc) {
+      doc = firstScorer.advance(doc);
+      first = first == scorers.length - 1 ? 0 : first + 1;
+    }
+    return doc;
+  }
+  
+  @Override
+  public int advance(int target) throws IOException {
+    if (lastDoc == NO_MORE_DOCS) {
+      return lastDoc;
+    } else if (scorers[(scorers.length - 1)].docID() < target) {
+      scorers[(scorers.length - 1)].advance(target);
+    }
+    return lastDoc = doNext();
+  }
+
+  @Override
+  public int docID() {
+    return lastDoc;
+  }
+  
+  @Override
+  public int nextDoc() throws IOException {
+    if (lastDoc == NO_MORE_DOCS) {
+      return lastDoc;
+    } else if (lastDoc == -1) {
+      return lastDoc = scorers[scorers.length - 1].docID();
+    }
+    scorers[(scorers.length - 1)].nextDoc();
+    return lastDoc = doNext();
+  }
+  
+  @Override
+  public float score() throws IOException {
+    float sum = 0.0f;
+    for (int i = 0; i < scorers.length; i++) {
+      sum += scorers[i].score();
+    }
+    return sum * coord;
+  }
+}