Class Extensions

The Extensions class represents an extension mapping to associate ParserExtension instances with extension keys. An extension key is a string encoded into a Lucene standard query parser field symbol recognized by ExtendableQueryParser. The query parser passes each extension field token to SplitExtensionField(String, String) to separate the extension key from the field identifier.

In addition to the key to extension mapping this class also defines the field name overloading scheme. ExtendableQueryParser uses the given extension to split the actual field name and extension key by calling SplitExtensionField(String, String). To change the order or the key / field name encoding scheme users can subclass Extensions to implement their own.

Inheritance

System.Object

Extensions

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: Lucene.Net.QueryParsers.Ext

Assembly: Lucene.Net.QueryParser.dll

Syntax

public class Extensions

Constructors

Extensions()

Creates a new Extensions instance with the DEFAULT_EXTENSION_FIELD_DELIMITER as a delimiter character.

Declaration

public Extensions()

Extensions(Char)

Creates a new Extensions instance

Declaration

public Extensions(char extensionFieldDelimiter)

Parameters

Type	Name	Description
System.Char	extensionFieldDelimiter	the extensions field delimiter character

Fields

DEFAULT_EXTENSION_FIELD_DELIMITER

The default extension field delimiter character. This constant is set to ':'

Declaration

public static readonly char DEFAULT_EXTENSION_FIELD_DELIMITER

Field Value

Type	Description
System.Char

Properties

ExtensionFieldDelimiter

Returns the extension field delimiter

Declaration

public virtual char ExtensionFieldDelimiter { get; }

Property Value

Type	Description
System.Char

Methods

Add(String, ParserExtension)

Adds a new ParserExtension instance associated with the given key.

Declaration

public virtual void Add(string key, ParserExtension extension)

Parameters

Type	Name	Description
System.String	key	the parser extension key
ParserExtension	extension	the parser extension

BuildExtensionField(String)

Builds an extension field string from a given extension key and the default query field. The default field and the key are delimited with the extension field delimiter character. This method makes no assumption about the order of the extension key and the field. By default the extension key is appended to the end of the returned string while the field is added to the beginning. Special Query characters are escaped in the result.

Note: Extensions subclasses must maintain the contract between BuildExtensionField(String) and BuildExtensionField(String, String) where the latter inverts the former.

Declaration

public virtual string BuildExtensionField(string extensionKey)

Parameters

Type	Name	Description
System.String	extensionKey	the extension key

Returns

Type	Description
System.String	escaped extension field identifier

BuildExtensionField(String, String)

Builds an extension field string from a given extension key and the default query field. The default field and the key are delimited with the extension field delimiter character. This method makes no assumption about the order of the extension key and the field. By default the extension key is appended to the end of the returned string while the field is added to the beginning. Special Query characters are escaped in the result.

Note: Extensions subclasses must maintain the contract between BuildExtensionField(String) and BuildExtensionField(String, String) where the latter inverts the former.

Declaration

public virtual string BuildExtensionField(string extensionKey, string field)

Parameters

Type	Name	Description
System.String	extensionKey	the extension key
System.String	field	the field to apply the extension on.

Returns

Type	Description
System.String	escaped extension field identifier

Remarks

See BuildExtensionField(String) to use the default query field

EscapeExtensionField(String)

Escapes an extension field. The default implementation is equivalent to Escape(String).

Declaration

public virtual string EscapeExtensionField(string extfield)

Parameters

Type	Name	Description
System.String	extfield	the extension field identifier

Returns

Type	Description
System.String	the extension field identifier with all special chars escaped with a backslash character.

GetExtension(String)

Returns the ParserExtension instance for the given key or

null

if no extension can be found for the key.

Declaration

public ParserExtension GetExtension(string key)

Parameters

Type	Name	Description
System.String	key	the extension key

Returns

Type	Description
ParserExtension	the ParserExtension instance for the given key or null if no extension can be found for the key.

SplitExtensionField(String, String)

Splits a extension field and returns the field / extension part as a Tuple{string,string}. This method tries to split on the first occurrence of the extension field delimiter, if the delimiter is not present in the string the result will contain a

null

value for the extension key and the given field string as the field value. If the given extension field string contains no field identifier the result pair will carry the given default field as the field value.

Declaration

public virtual Tuple<string, string> SplitExtensionField(string defaultField, string field)

Parameters

Type	Name	Description
System.String	defaultField	the default query field
System.String	field	the extension field string

Returns

Type	Description
System.Tuple<System.String, System.String>	a {System.Tuple<T1, T2> with the field name as the System.Tuple`2.Item1 and the extension key as the System.Tuple`2.Item2

See Also

ExtendableQueryParser

ParserExtension