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/TermScorer.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/TermScorer.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/TermScorer.java
new file mode 100644
index 0000000..d28639b
--- /dev/null
+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/TermScorer.java
@@ -0,0 +1,172 @@
+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.TermDocs;
+
+/** Expert: A <code>Scorer</code> for documents matching a <code>Term</code>.
+ */
+final class TermScorer extends Scorer {
+  private final TermDocs termDocs;
+  private final byte[] norms;
+  private float weightValue;
+  private int doc = -1;
+  private int freq;
+
+  private final int[] docs = new int[32];         // buffered doc numbers
+  private final int[] freqs = new int[32];        // buffered term freqs
+  private int pointer;
+  private int pointerMax;
+
+  private static final int SCORE_CACHE_SIZE = 32;
+  private final float[] scoreCache = new float[SCORE_CACHE_SIZE];
+
+  /**
+   * Construct a <code>TermScorer</code>.
+   * 
+   * @param weight
+   *          The weight of the <code>Term</code> in the query.
+   * @param td
+   *          An iterator over the documents matching the <code>Term</code>.
+   * @param similarity
+   *          The </code>Similarity</code> implementation to be used for score
+   *          computations.
+   * @param norms
+   *          The field norms of the document fields for the <code>Term</code>.
+   */
+  TermScorer(Weight weight, TermDocs td, Similarity similarity, byte[] norms) {
+    super(similarity, weight);
+    
+    this.termDocs = td;
+    this.norms = norms;
+    this.weightValue = weight.getValue();
+
+    for (int i = 0; i < SCORE_CACHE_SIZE; i++)
+      scoreCache[i] = getSimilarity().tf(i) * weightValue;
+  }
+
+  @Override
+  public void score(Collector c) throws IOException {
+    score(c, Integer.MAX_VALUE, nextDoc());
+  }
+
+  // firstDocID is ignored since nextDoc() sets 'doc'
+  @Override
+  protected boolean score(Collector c, int end, int firstDocID) throws IOException {
+    c.setScorer(this);
+    while (doc < end) {                           // for docs in window
+      c.collect(doc);                      // collect score
+        
+      if (++pointer >= pointerMax) {
+        pointerMax = termDocs.read(docs, freqs);  // refill buffers
+        if (pointerMax != 0) {
+          pointer = 0;
+        } else {
+          termDocs.close();                       // close stream
+          doc = Integer.MAX_VALUE;                // set to sentinel value
+          return false;
+        }
+      } 
+      doc = docs[pointer];
+      freq = freqs[pointer];
+    }
+    return true;
+  }
+
+  @Override
+  public int docID() { return doc; }
+
+  @Override
+  public float freq() {
+    return freq;
+  }
+
+  /**
+   * Advances to the next document matching the query. <br>
+   * The iterator over the matching documents is buffered using
+   * {@link TermDocs#read(int[],int[])}.
+   * 
+   * @return the document matching the query or NO_MORE_DOCS if there are no more documents.
+   */
+  @Override
+  public int nextDoc() throws IOException {
+    pointer++;
+    if (pointer >= pointerMax) {
+      pointerMax = termDocs.read(docs, freqs);    // refill buffer
+      if (pointerMax != 0) {
+        pointer = 0;
+      } else {
+        termDocs.close();                         // close stream
+        return doc = NO_MORE_DOCS;
+      }
+    } 
+    doc = docs[pointer];
+    freq = freqs[pointer];
+    return doc;
+  }
+  
+  @Override
+  public float score() {
+    assert doc != -1;
+    float raw =                                   // compute tf(f)*weight
+      freq < SCORE_CACHE_SIZE                        // check cache
+      ? scoreCache[freq]                             // cache hit
+      : getSimilarity().tf(freq)*weightValue;        // cache miss
+
+    return norms == null ? raw : raw * getSimilarity().decodeNormValue(norms[doc]); // normalize for field
+  }
+
+  /**
+   * Advances to the first match beyond the current whose document number is
+   * greater than or equal to a given target. <br>
+   * The implementation uses {@link TermDocs#skipTo(int)}.
+   * 
+   * @param target
+   *          The target document number.
+   * @return the matching document or NO_MORE_DOCS if none exist.
+   */
+  @Override
+  public int advance(int target) throws IOException {
+    // first scan in cache
+    for (pointer++; pointer < pointerMax; pointer++) {
+      if (docs[pointer] >= target) {
+    	freq = freqs[pointer];
+        return doc = docs[pointer];
+      }
+    }
+
+    // not found in cache, seek underlying stream
+    boolean result = termDocs.skipTo(target);
+    if (result) {
+      pointerMax = 1;
+      pointer = 0;
+      docs[pointer] = doc = termDocs.doc();
+      freqs[pointer] = freq = termDocs.freq();
+    } else {
+      doc = NO_MORE_DOCS;
+    }
+    return doc;
+  }
+  
+  /** Returns a string representation of this <code>TermScorer</code>. */
+  @Override
+  public String toString() { return "scorer(" + weight + ")"; }
+
+}