mirror of https://github.com/apache/lucene.git
31 lines
2.0 KiB
Plaintext
31 lines
2.0 KiB
Plaintext
This module contains a number of filter and query objects that add to core lucene.
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==== TrieRangeFilter/TrieRangeQuery - This package provides fast numeric range queries/filters on long,
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double or Date fields based on trie structures. Numerical values are stored in a special string-encoded
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format with variable precision (all numerical values like doubles, longs, and timestamps are converted
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to lexicographic sortable string representations). A range is then divided recursively into multiple
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intervals for searching: The center of the range is searched only with the lowest possible precision
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in the trie, the boundaries are matched more exactly. This reduces the number of terms and thus improves
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dramatically the performance of range queries, on the cost of larger index sizes.
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==== The "MoreLikeThis" class from the "similarity" module has been copied into here.
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If people are generally happy with this move then the similarity module can be deleted, or at least a
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"Moved to queries module..." note left in its place.
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==== FuzzyLikeThis - mixes the behaviour of FuzzyQuery and MoreLikeThis but with special consideration
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of fuzzy scoring factors. This generally produces good results for queries where users may provide details in a number of
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fields and have no knowledge of boolean query syntax and also want a degree of fuzzy matching. The query is fast because, like
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MoreLikeThis, it optimizes the query to only the most distinguishing terms.
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==== BoostingQuery - effectively demotes search results that match a given query.
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Unlike the "NOT" clause, this still selects documents that contain undesirable terms,
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but reduces the overall score of docs containing these terms.
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==== TermsFilter - Unlike a RangeFilter this can be used for filtering on multiple terms that are not necessarily in
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a sequence. An example might be a collection of primary keys from a database query result or perhaps
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a choice of "category" labels picked by the end user.
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Mark Harwood & Uwe Schindler
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05/12/2008
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