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+<html>
+<head>
+ <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+</head>
+<body>
+
+Interfaces and implementations used by query node processors
+
+<h2>Query Node Processors</h2>
+<p>
+The package <tt>org.apache.lucene.queryParser.processors</tt> contains interfaces
+that should be implemented by every query node processor.
+</p>
+<p>
+The interface that every query node processor should implement is {@link org.apache.lucene.queryParser.core.processors.QueryNodeProcessor}.
+</p>
+<p>
+A query node processor should be used to process a {@link org.apache.lucene.queryParser.core.nodes.QueryNode} tree.
+{@link org.apache.lucene.queryParser.core.nodes.QueryNode} trees can be programmatically created or generated by a
+text parser. See {@link org.apache.lucene.queryParser.core.parser} for more details about text parsers.
+</p>
+
+<p>
+A query node processor should be used to process a {@link org.apache.lucene.queryParser.core.nodes.QueryNode} tree.
+{@link org.apache.lucene.queryParser.core.nodes.QueryNode} trees can be programmatically created or generated by a
+text parser. See {@link org.apache.lucene.queryParser.core.parser} for more details about text parsers.
+</p>
+
+<p>
+A pipeline of processors can be assembled using {@link org.apache.lucene.queryParser.core.processors.QueryNodeProcessorPipeline}.
+</p>
+
+<p>
+Implementors may want to extend {@link org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl}, which simplifies
+the implementation, because it walks automatically the {@link org.apache.lucene.queryParser.core.nodes.QueryNode}. See
+{@link org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl} for more details.
+</p>
+
+</body>
+</html>