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Lucene example source code file (CachedFilter.xml)

This example Lucene source code file (CachedFilter.xml) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

booleanquery, cache, cachedfilter, cachedfilter, clause, clause, filter, filteredquery, lru, query, query, termquery, termquery, the

The Lucene CachedFilter.xml source code

<?xml version="1.0" encoding="UTF-8"?>
<FilteredQuery>
	<Query>
		<BooleanQuery fieldName="contents">
			<Clause occurs="should">
				<TermQuery>merger
			</Clause>
			<Clause occurs="mustnot">
				<TermQuery >sumitomo		
			</Clause>
		</BooleanQuery>
	</Query>
	
	<Filter>
		<!--
			CachedFilter elements can contain any Query or Filter. 
			CachedFilters are cached in an LRU Cache keyed on the contained query/filter object. 
			Using this will speed up overall performance for repeated uses of the same expensive 
			query/filter. The sorts of queries likely to benefit from caching need not necessarily be 
			complex - e.g. simple TermQuerys with a large DF (document frequency) can be expensive
			on large indexes. A good example of this might be a term query on a field with only 2 possible 
			values - "true" or "false". In a large index, querying or filtering on this field requires 
			reading millions of document ids from disk which can more usefully be cached as a 
			QueryFilter bitset.
			
			For Queries/Filters to be cached and reused the object must implement hashcode and
			equals methods correctly so that duplicate queries/filters can be detected in the cache.
			
			The CoreParser.maxNumCachedFilters property can be used to control the size
			of the LRU Cache established during the construction of CoreParser instances.
			-->
		<CachedFilter>
			<!-- Example query to be cached for fast, repeated use -->
			<TermQuery fieldName="contents">bank 
			<!-- Alternatively, a filter object can be cached ....
				<RangeFilter fieldName="date" lowerTerm="19870409" upperTerm="19870412"/>
			-->				
		</CachedFilter>
	</Filter>
	
</FilteredQuery>

Other Lucene examples (source code examples)

Here is a short list of links related to this Lucene CachedFilter.xml source code file:



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