pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / highlighter / src / java / org / apache / lucene / search / highlight / SimpleSpanFragmenter.java

diff --git a/lucene-java-3.5.0/lucene/contrib/highlighter/src/java/org/apache/lucene/search/highlight/SimpleSpanFragmenter.java b/lucene-java-3.5.0/lucene/contrib/highlighter/src/java/org/apache/lucene/search/highlight/SimpleSpanFragmenter.java
new file mode 100644 (file)
index 0000000..c468867
--- /dev/null
+++ b/lucene-java-3.5.0/lucene/contrib/highlighter/src/java/org/apache/lucene/search/highlight/SimpleSpanFragmenter.java
@@ -0,0 +1,108 @@
+package org.apache.lucene.search.highlight;
+
+
+/**
+ * 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.util.List;
+
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
+import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
+import org.apache.lucene.search.spans.Spans;
+
+
+/**
+ * {@link Fragmenter} implementation which breaks text up into same-size
+ * fragments but does not split up {@link Spans}. This is a simple sample class.
+ */
+public class SimpleSpanFragmenter implements Fragmenter {
+  private static final int DEFAULT_FRAGMENT_SIZE = 100;
+  private int fragmentSize;
+  private int currentNumFrags;
+  private int position = -1;
+  private QueryScorer queryScorer;
+  private int waitForPos = -1;
+  private int textSize;
+  private CharTermAttribute termAtt;
+  private PositionIncrementAttribute posIncAtt;
+  private OffsetAttribute offsetAtt;
+
+  /**
+   * @param queryScorer QueryScorer that was used to score hits
+   */
+  public SimpleSpanFragmenter(QueryScorer queryScorer) {
+    this(queryScorer, DEFAULT_FRAGMENT_SIZE);
+  }
+
+  /**
+   * @param queryScorer QueryScorer that was used to score hits
+   * @param fragmentSize size in bytes of each fragment
+   */
+  public SimpleSpanFragmenter(QueryScorer queryScorer, int fragmentSize) {
+    this.fragmentSize = fragmentSize;
+    this.queryScorer = queryScorer;
+  }
+  
+  /* (non-Javadoc)
+   * @see org.apache.lucene.search.highlight.Fragmenter#isNewFragment()
+   */
+  public boolean isNewFragment() {
+    position += posIncAtt.getPositionIncrement();
+
+    if (waitForPos == position) {
+      waitForPos = -1;
+    } else if (waitForPos != -1) {
+      return false;
+    }
+
+    WeightedSpanTerm wSpanTerm = queryScorer.getWeightedSpanTerm(termAtt.toString());
+
+    if (wSpanTerm != null) {
+      List<PositionSpan> positionSpans = wSpanTerm.getPositionSpans();
+
+      for (int i = 0; i < positionSpans.size(); i++) {
+        if (positionSpans.get(i).start == position) {
+          waitForPos = positionSpans.get(i).end + 1;
+          break;
+        }
+      }
+    }
+
+    boolean isNewFrag = offsetAtt.endOffset() >= (fragmentSize * currentNumFrags)
+        && (textSize - offsetAtt.endOffset()) >= (fragmentSize >>> 1);
+    
+    if (isNewFrag) {
+      currentNumFrags++;
+    }
+
+    return isNewFrag;
+  }
+
+
+  /* (non-Javadoc)
+   * @see org.apache.lucene.search.highlight.Fragmenter#start(java.lang.String, org.apache.lucene.analysis.TokenStream)
+   */
+  public void start(String originalText, TokenStream tokenStream) {
+    position = -1;
+    currentNumFrags = 1;
+    textSize = originalText.length();
+    termAtt = tokenStream.addAttribute(CharTermAttribute.class);
+    posIncAtt = tokenStream.addAttribute(PositionIncrementAttribute.class);
+    offsetAtt = tokenStream.addAttribute(OffsetAttribute.class);
+  }
+}