Namespace Lucene.Net.QueryParsers.Flexible.Core.Nodes

Query nodes commonly used by query parser implementations.

Query Nodes

The namespace Lucene.Net.QueryParsers.Flexible.Core.Nodes contains all the basic query nodes. The interface that represents a query node is IQueryNode.

IQueryNodes are used by the text parser to create a syntax tree. These nodes are designed to be used by UI or other text parsers. The default Lucene text parser is StandardSyntaxParser, it implements Lucene's standard syntax.

IQueryNode interface should be implemented by all query nodes, the class QueryNode implements IQueryNode and is extended by all current query node implementations.

A query node tree can be printed to the a stream, and it generates a pseudo XML representation with all the nodes.

A query node tree can also generate a query string that can be parsed back by the original text parser, at this point only the standard lucene syntax is supported.

Grouping nodes:

AndQueryNode - used for AND operator
AnyQueryNode - used for ANY operator
OrQueryNode - used for OR operator
BooleanQueryNode - used when no operator is specified
ModifierQueryNode - used for modifier operator
GroupQueryNode - used for parenthesis
BoostQueryNode - used for boost operator
SlopQueryNode - phrase slop
FuzzyQueryNode - fuzzy node
TermRangeQueryNode - used for parametric field:[low_value TO high_value]
ProximityQueryNode - used for proximity search
NumericRangeQueryNode - used for numeric range search
TokenizedPhraseQueryNode - used by tokenizers/lemmatizers/analyzers for phrases/autophrases

Leaf Nodes:
FieldQueryNode - field/value node
NumericQueryNode - used for numeric search
PathQueryNode - IQueryNode object used with path-like queries
OpaqueQueryNode - Used as for part of the query that can be parsed by other parsers. schema/value
PrefixWildcardQueryNode - non-phrase wildcard query
QuotedFieldQUeryNode - regular phrase node
WildcardQueryNode - non-phrase wildcard query

Utility Nodes:
DeletedQueryNode - used by processors on optimizations
MatchAllDocsQueryNode - used by processors on optimizations
MatchNoDocsQueryNode - used by processors on optimizations
NoTokenFoundQueryNode - used by tokenizers/lemmatizers/analyzers

Classes

AndQueryNode

A AndQueryNode represents an AND boolean operation performed on a list of nodes.

AnyQueryNode

A AnyQueryNode represents an ANY operator performed on a list of nodes.

BooleanQueryNode

A BooleanQueryNode represents a list of elements which do not have an explicit boolean operator defined between them. It can be used to express a boolean query that intends to use the default boolean operator.

BoostQueryNode

A BoostQueryNode boosts the QueryNode tree which is under this node. So, it must only and always have one child.

The boost value may vary from 0.0 to 1.0.

DeletedQueryNode

A DeletedQueryNode represents a node that was deleted from the query node tree. It can be removed from the tree using the RemoveDeletedQueryNodesProcessor processor.

FieldQueryNode

A FieldQueryNode represents a element that contains field/text tuple

FuzzyQueryNode

A FuzzyQueryNode represents a element that contains field/text/similarity tuple

GroupQueryNode

A GroupQueryNode represents a location where the original user typed real parenthesis on the query string. This class is useful for queries like: a) a AND b OR c b) ( a AND b) OR c

Parenthesis might be used to define the boolean operation precedence.

MatchAllDocsQueryNode

A MatchAllDocsQueryNode indicates that a query node tree or subtree will match all documents if executed in the index.

MatchNoDocsQueryNode

A MatchNoDocsQueryNode indicates that a query node tree or subtree will not match any documents if executed in the index.

ModifierExtensions

ModifierQueryNode

A ModifierQueryNode indicates the modifier value (+,-,?,NONE) for each term on the query string. For example "+t1 -t2 t3" will have a tree of:

<BooleanQueryNode> <ModifierQueryNode modifier="MOD_REQ"> <t1/> </ModifierQueryNode> <ModifierQueryNode modifier="MOD_NOT"> <t2/> </ModifierQueryNode> <t3/> </BooleanQueryNode>

NoTokenFoundQueryNode

A NoTokenFoundQueryNode is used if a term is convert into no tokens by the tokenizer/lemmatizer/analyzer (null).

OpaqueQueryNode

A OpaqueQueryNode is used for specify values that are not supposed to be parsed by the parser. For example: and XPATH query in the middle of a query string a b @xpath:'/bookstore/book[1]/title' c d

OrQueryNode

A OrQueryNode represents an OR boolean operation performed on a list of nodes.

PathQueryNode

A PathQueryNode is used to store queries like /company/USA/California /product/shoes/brown. QueryText are objects that contain the text, begin position and end position in the query.

Example how the text parser creates these objects:

IList<PathQueryNode.QueryText> values = new List<PathQueryNode.QueryText>();
values.Add(new PathQueryNode.QueryText("company", 1, 7));
values.Add(new PathQueryNode.QueryText("USA", 9, 12));
values.Add(new PathQueryNode.QueryText("California", 14, 23));
QueryNode q = new PathQueryNode(values);

PathQueryNode.QueryText

Term text with a beginning and end position

PhraseSlopQueryNode

Query node for PhraseQuery's slop factor.

ProximityQueryNode

A ProximityQueryNode represents a query where the terms should meet specific distance conditions. (a b c) WITHIN [SENTENCE|PARAGRAPH|NUMBER] [INORDER] ("a" "b" "c") WITHIN [SENTENCE|PARAGRAPH|NUMBER] [INORDER]

TODO: Add this to the future standard Lucene parser/processor/builder

ProximityQueryNode_TypeExtensions

ProximityType

utility class containing the distance condition and number

QueryNode

A QueryNode is the default implementation of the interface IQueryNode

QuotedFieldQueryNode

A QuotedFieldQueryNode represents phrase query. Example: "life is great"

SlopQueryNode

A SlopQueryNode represents phrase query with a slop.

From Lucene FAQ: Is there a way to use a proximity operator (like near or within) with Lucene? There is a variable called slop that allows you to perform NEAR/WITHIN-like queries. By default, slop is set to 0 so that only exact phrases will match. When using TextParser you can use this syntax to specify the slop: "doug cutting"~2 will find documents that contain "doug cutting" as well as ones that contain "cutting doug".

TokenizedPhraseQueryNode

A TokenizedPhraseQueryNode represents a node created by a code that tokenizes/lemmatizes/analyzes.