--- /dev/null
+<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
+<!--
+ 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.
+-->
+<html>
+<body>
+
+The highlight package contains classes to provide "keyword in context" features
+typically used to highlight search terms in the text of results pages.
+The Highlighter class is the central component and can be used to extract the
+most interesting sections of a piece of text and highlight them, with the help of
+Fragmenter, fragment Scorer, and Formatter classes.
+
+<h2>Example Usage</h2>
+
+<pre class="prettyprint">
+ //... Above, create documents with two fields, one with term vectors (tv) and one without (notv)
+ IndexSearcher searcher = new IndexSearcher(directory);
+ QueryParser parser = new QueryParser("notv", analyzer);
+ Query query = parser.parse("million");
+
+ TopDocs hits = searcher.search(query, 10);
+
+ SimpleHTMLFormatter htmlFormatter = new SimpleHTMLFormatter();
+ Highlighter highlighter = new Highlighter(htmlFormatter, new QueryScorer(query));
+ for (int i = 0; i < 10; i++) {
+ int id = hits.scoreDocs[i].doc;
+ Document doc = searcher.doc(id);
+ String text = doc.get("notv");
+ TokenStream tokenStream = TokenSources.getAnyTokenStream(searcher.getIndexReader(), id, "notv", analyzer);
+ TextFragment[] frag = highlighter.getBestTextFragments(tokenStream, text, false, 10);//highlighter.getBestFragments(tokenStream, text, 3, "...");
+ for (int j = 0; j < frag.length; j++) {
+ if ((frag[j] != null) && (frag[j].getScore() > 0)) {
+ System.out.println((frag[j].toString()));
+ }
+ }
+ //Term vector
+ text = doc.get("tv");
+ tokenStream = TokenSources.getAnyTokenStream(searcher.getIndexReader(), hits.scoreDocs[i].doc, "tv", analyzer);
+ frag = highlighter.getBestTextFragments(tokenStream, text, false, 10);
+ for (int j = 0; j < frag.length; j++) {
+ if ((frag[j] != null) && (frag[j].getScore() > 0)) {
+ System.out.println((frag[j].toString()));
+ }
+ }
+ System.out.println("-------------");
+ }
+</pre>
+
+<h2>New features 06/02/2005</h2>
+
+This release adds options for encoding (thanks to Nicko Cadell).
+An "Encoder" implementation such as the new SimpleHTMLEncoder class can be passed to the highlighter to encode
+all those non-xhtml standard characters such as & into legal values. This simple class may not suffice for
+some languages - Commons Lang has an implementation that could be used: escapeHtml(String) in
+http://svn.apache.org/viewcvs.cgi/jakarta/commons/proper/lang/trunk/src/java/org/apache/commons/lang/StringEscapeUtils.java?rev=137958&view=markup
+
+<h2>New features 22/12/2004</h2>
+
+This release adds some new capabilities:
+<ol>
+ <li>Faster highlighting using Term vector support</li>
+ <li>New formatting options to use color intensity to show informational value</li>
+ <li>Options for better summarization by using term IDF scores to influence fragment selection</li>
+</ol>
+
+<p>
+The highlighter takes a TokenStream as input. Until now these streams have typically been produced
+using an Analyzer but the new class TokenSources provides helper methods for obtaining TokenStreams from
+the new TermVector position support (see latest CVS version).</p>
+
+<p>The new class GradientFormatter can use a scale of colors to highlight terms according to their score.
+A subtle use of color can help emphasise the reasons for matching (useful when doing "MoreLikeThis" queries and
+you want to see what the basis of the similarities are).</p>
+
+<p>The QueryScorer class has a new constructor which can use an IndexReader to derive the IDF (inverse document frequency)
+for each term in order to influence the score. This is useful for helping to extracting the most significant sections
+of a document and in supplying scores used by the new GradientFormatter to color significant words more strongly.
+The QueryScorer.getMaxWeight method is useful when passed to the GradientFormatter constructor to define the top score
+which is associated with the top color.</p>
+
+
+
+
+</body>
+</html>
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fnp / pylucene.git / blobdiff