src/Lucene.Net.QueryParser/Flexible/Core/Processors/package.md

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uid: Lucene.Net.QueryParsers.Flexible.Core.Processors
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Interfaces and implementations used by query node processors

## Query Node Processors

The namespace <tt>Lucene.Net.QueryParsers.Flexible.Core.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.IQueryNodeProcessor>.

A query node processor should be used to process a <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.IQueryNode> tree. <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.IQueryNode> 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.IQueryNode> tree. <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.IQueryNode> 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.QueryNodeProcessor>, which simplifies the implementation, because it walks automatically the <xref:Lucene.Net.QueryParsers.Flexible.Core.Nodes.IQueryNode>. See <xref:Lucene.Net.QueryParsers.Flexible.Core.Processors.QueryNodeProcessor> for more details.