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Interfaces and implementations used by query node processors

## Query Node Processors

 The package <tt>org.apache.lucene.queryParser.processors</tt> contains interfaces that should be implemented by every query node processor. 

 The interface that every query node processor should implement is <xref:Lucene.Net.QueryParsers.Flexible.Core.Processors.QueryNodeProcessor>. 

 A query node processor should be used to process a <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.QueryNode> tree. <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.QueryNode> trees can be programmatically created or generated by a text parser. See <xref:Lucene.Net.QueryParsers.Flexible.Core.Parser> for more details about text parsers. 

 A query node processor should be used to process a <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.QueryNode> tree. <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.QueryNode> trees can be programmatically created or generated by a text parser. See <xref:Lucene.Net.QueryParsers.Flexible.Core.Parser> for more details about text parsers. 

 A pipeline of processors can be assembled using <xref:Lucene.Net.QueryParsers.Flexible.Core.Processors.QueryNodeProcessorPipeline>. 

 Implementors may want to extend <xref:Lucene.Net.QueryParsers.Flexible.Core.Processors.QueryNodeProcessorImpl>, which simplifies the implementation, because it walks automatically the <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.QueryNode>. See <xref:Lucene.Net.QueryParsers.Flexible.Core.Processors.QueryNodeProcessorImpl> for more details. 