Class FastCharStream
java.lang.Object
org.apache.lucene.queryparser.charstream.FastCharStream
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CharStream
An efficient implementation of JavaCC's CharStream 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 OffsetAttribute API.
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionfinal voidbackup(int amount) Backs up the input stream by amount steps.final charReturns the next character that marks the beginning of the next token.final voidDone()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.final intReturns the column number of the first character for current token (being matched after the last call to BeginTOken).final intReturns the line number of the first character for current token (being matched after the last call to BeginTOken).final intReturns the column number of the last character for current token (being matched after the last call to BeginTOken).final intReturns the line number of the last character for current token (being matched after the last call to BeginTOken).final StringGetImage()Returns a string made up of characters from the marked token beginning to the current buffer position.final char[]GetSuffix(int len) Returns an array of characters that make up the suffix of length 'len' for the currently matched token.final charreadChar()Returns the next character from the selected input.
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Constructor Details
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FastCharStream
Constructs from a Reader.
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Method Details
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readChar
Description copied from interface:CharStreamReturns 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.- Specified by:
readCharin interfaceCharStream- Throws:
IOException
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BeginToken
Description copied from interface:CharStreamReturns 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.- Specified by:
BeginTokenin interfaceCharStream- Throws:
IOException
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backup
public final void backup(int amount) Description copied from interface:CharStreamBacks 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 implementation's responsibility to do this right.- Specified by:
backupin interfaceCharStream
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GetImage
Description copied from interface:CharStreamReturns 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.- Specified by:
GetImagein interfaceCharStream
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GetSuffix
public final char[] GetSuffix(int len) Description copied from interface:CharStreamReturns 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(); }
- Specified by:
GetSuffixin interfaceCharStream
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Done
public final void Done()Description copied from interface:CharStreamThe 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.- Specified by:
Donein interfaceCharStream
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getEndColumn
public final int getEndColumn()Description copied from interface:CharStreamReturns the column number of the last character for current token (being matched after the last call to BeginTOken).- Specified by:
getEndColumnin interfaceCharStream
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getEndLine
public final int getEndLine()Description copied from interface:CharStreamReturns the line number of the last character for current token (being matched after the last call to BeginTOken).- Specified by:
getEndLinein interfaceCharStream
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getBeginColumn
public final int getBeginColumn()Description copied from interface:CharStreamReturns the column number of the first character for current token (being matched after the last call to BeginTOken).- Specified by:
getBeginColumnin interfaceCharStream
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getBeginLine
public final int getBeginLine()Description copied from interface:CharStreamReturns the line number of the first character for current token (being matched after the last call to BeginTOken).- Specified by:
getBeginLinein interfaceCharStream
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