--- /dev/null
+<html>
+ <head>
+ <title>Aggregating Facets during Faceted Search</title>
+ </head>
+ <body>
+ <h1>Aggregating Facets during Faceted Search</h1>
+
+ A facets aggregator is the parallel of Lucene's Collector.
+ While Collector collected matching documents,
+ an aggregator aggregates facets of a matching document.
+ </body>
+</html>
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