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Query nodes commonly used by query parser implementations.
Query Nodes

The package org.apache.lucene.queryParser.nodes contains all the basic query nodes. The interface that represents a query node is QueryNode. 
 QueryNodes 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. 
 QueryNode interface should be implemented by all query nodes, the class QueryNodeImpl implements QueryNode 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
LegacyNumericRangeQueryNode - used for numeric range search
TokenizedPhraseQueryNode - used by tokenizers/lemmatizers/analyzers for phrases/autophrases


Leaf Nodes:

FieldQueryNode - field/value node
LegacyNumericQueryNode - used for numeric search
PathQueryNode - QueryNode 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

/** 
 * Query nodes commonly used by query parser implementations.
 *
 * <h2>Query Nodes</h2>
 * <p>
 * The package <tt>org.apache.lucene.queryParser.nodes</tt> contains all the basic query nodes. The interface 
 * that represents a query node is {@link org.apache.lucene.queryparser.flexible.core.nodes.QueryNode}.
 * <p>
 * {@link org.apache.lucene.queryparser.flexible.core.nodes.QueryNode}s 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 {@link org.apache.lucene.queryparser.flexible.standard.parser.StandardSyntaxParser},
 * it implements Lucene's standard syntax.
 * <p>
 * {@link org.apache.lucene.queryparser.flexible.core.nodes.QueryNode} interface should be implemented by all query nodes,
 * the class {@link org.apache.lucene.queryparser.flexible.core.nodes.QueryNodeImpl} implements {@link org.apache.lucene.queryparser.flexible.core.nodes.QueryNode} and is extended
 * by all current query node implementations.
 * <p>
 * A query node tree can be printed to the a stream, and it generates a pseudo XML representation
 * with all the nodes.
 * </p>
 * <p>
 * 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.
 * <p>
 * Grouping nodes:
 * <ul>
 * <li>AndQueryNode - used for AND operator</li>
 * <li>AnyQueryNode - used for ANY operator</li>
 * <li>OrQueryNode - used for OR operator</li>
 * <li>BooleanQueryNode - used when no operator is specified</li>
 * <li>ModifierQueryNode - used for modifier operator</li>
 * <li>GroupQueryNode - used for parenthesis</li>
 * <li>BoostQueryNode - used for boost operator</li>
 * <li>SlopQueryNode - phrase slop</li>
 * <li>FuzzyQueryNode - fuzzy node</li>
 * <li>TermRangeQueryNode - used for parametric field:[low_value TO high_value]</li>
 * <li>ProximityQueryNode - used for proximity search</li>
 * <li>LegacyNumericRangeQueryNode - used for numeric range search</li>
 * <li>TokenizedPhraseQueryNode - used by tokenizers/lemmatizers/analyzers for phrases/autophrases</li>
 * </ul>
 * <p>
 * Leaf Nodes:
 * <ul>
 * <li>FieldQueryNode - field/value node</li>
 * <li>LegacyNumericQueryNode - used for numeric search</li>
 * <li>PathQueryNode - {@link org.apache.lucene.queryparser.flexible.core.nodes.QueryNode} object used with path-like queries</li>
 * <li>OpaqueQueryNode - Used as for part of the query that can be parsed by other parsers. schema/value</li> 
 * <li>PrefixWildcardQueryNode - non-phrase wildcard query</li>
 * <li>QuotedFieldQUeryNode - regular phrase node</li>
 * <li>WildcardQueryNode - non-phrase wildcard query</li>
 * </ul>
 * <p>
 * Utility Nodes:
 * <ul>
 * <li>DeletedQueryNode - used by processors on optimizations</li>
 * <li>MatchAllDocsQueryNode - used by processors on optimizations</li>
 * <li>MatchNoDocsQueryNode - used by processors on optimizations</li>
 * <li>NoTokenFoundQueryNode - used by tokenizers/lemmatizers/analyzers</li>
 * </ul>
 */
package org.apache.lucene.queryparser.flexible.core.nodes;