DotLucene 1.4 API Documentation |

# CharStream Methods

The methods of the CharStream interface are listed below. For a complete list of CharStream interface members, see the CharStream Members topic.

#### Public Instance Methods

Backup | 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.
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 correctly.
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.
GetBeginColumn | Returns the column number of the first character for current token (being matched after the last call to BeginTOken).
GetBeginLine | Returns the line number of the first character for current token (being matched after the last call to BeginTOken).
GetColumn | Returns the column position of the character last read.
GetEndColumn | Returns the column number of the last character for current token (being matched after the last call to BeginTOken).
GetEndLine | Returns the line number of the last character for current token (being matched after the last call to BeginTOken).
GetImage | 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.
GetLine | Returns the line number of the character last read.
GetSuffix | 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 = GetImage(); return t.substring(t.length() - len, t.length()).toCharArray(); }
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 java.io.IOException.

#### See Also

CharStream Interface | Lucene.Net.Analysis.Standard Namespace