Class FastCharStream

An efficient implementation of JavaCC's ICharStream interface.

Note that this does not do line-number counting, but instead keeps track of the character position of the token in the input, as required by Lucene's Lucene.Net.Analysis.Token API.
Inheritance
object
FastCharStream
Implements
Inherited Members
Namespace: Lucene.Net.QueryParsers.Classic
Assembly: Lucene.Net.QueryParser.dll
Syntax
public sealed class FastCharStream : ICharStream

Constructors

FastCharStream(TextReader)

Constructs from a TextReader.

Declaration
public FastCharStream(TextReader r)
Parameters
Type Name Description
TextReader r

Properties

BeginColumn

Returns the column number of the first character for current token (being matched after the last call to BeginTOken).

Declaration
public int BeginColumn { get; }
Property Value
Type Description
int

BeginLine

Returns the line number of the first character for current token (being matched after the last call to BeginTOken).

Declaration
public int BeginLine { get; }
Property Value
Type Description
int

Column

Returns the column position of the character last read.

Declaration
public int Column { get; }
Property Value
Type Description
int
See Also

EndColumn

Returns the column number of the last character for current token (being matched after the last call to BeginTOken).

Declaration
public int EndColumn { get; }
Property Value
Type Description
int

EndLine

Returns the line number of the last character for current token (being matched after the last call to BeginTOken).

Declaration
public int EndLine { get; }
Property Value
Type Description
int

Image

Returns a string made up of characters from the marked token beginning to the current buffer position. Implementations have the choice of returning anything that they want to. For example, for efficiency, one might decide to just return null, which is a valid implementation.

Declaration
public string Image { get; }
Property Value
Type Description
string

Line

Returns the line number of the character last read.

Declaration
public int Line { get; }
Property Value
Type Description
int
See Also

Methods

BackUp(int)

Backs up the input stream by amount steps. Lexer calls this method if it had already read some characters, but could not use them to match a (longer) token. So, they will be used again as the prefix of the next token and it is the implemetation's responsibility to do this right.

Declaration
public void BackUp(int amount)
Parameters
Type Name Description
int amount

BeginToken()

Returns the next character that marks the beginning of the next token. All characters must remain in the buffer between two successive calls to this method to implement BackUp(int) correctly.

Declaration
public char BeginToken()
Returns
Type Description
char

Done()

The lexer calls this function to indicate that it is done with the stream and hence implementations can free any resources held by this class. Again, the body of this function can be just empty and it will not affect the lexer's operation.

Declaration
public void Done()

GetSuffix(int)

Returns an array of characters that make up the suffix of length 'len' for the currently matched token. This is used to build up the matched string for use in actions in the case of MORE. A simple and inefficient implementation of this is as follows :

{
    string t = Image;
    return t.Substring(t.Length - len, len).ToCharArray();
}
Declaration
public char[] GetSuffix(int len)
Parameters
Type Name Description
int len
Returns
Type Description
char[]

ReadChar()

Returns the next character from the selected input. The method of selecting the input is the responsibility of the class implementing this interface. Can throw any IOException.

Declaration
public char ReadChar()
Returns
Type Description
char

Implements