org.apache.derby.impl.sql.compile

Class UCode_CharStream

java.lang.Object

org.apache.derby.impl.sql.compile.UCode_CharStream

public final class UCode_CharStream
extends java.lang.Object

An implementation of interface CharStream, where the stream is assumed to contain only Unicode characters.

Field Summary

Fields

Modifier and Type	Field and Description
int	bufpos
static boolean	staticFlag

Constructor Summary

Constructors

Constructor and Description
UCode_CharStream(java.io.InputStream dstream, int startline, int startcolumn)
UCode_CharStream(java.io.InputStream dstream, int startline, int startcolumn, int buffersize)
UCode_CharStream(java.io.Reader dstream, int startline, int startcolumn)
UCode_CharStream(java.io.Reader dstream, int startline, int startcolumn, int buffersize)

Method Summary

Modifier and Type	Method and Description
void	adjustBeginLineColumn(int newLine, int newCol) Method to adjust line and column numbers for the start of a token.
void	backup(int amount) Backs up the input stream by amount steps.
char	BeginToken() Returns the next character that marks the beginning of the next token.
void	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.
int	getBeginColumn() Returns the column number of the first character for current token (being matched after the last call to BeginTOken).
int	getBeginLine() Returns the line number of the first character for current token (being matched after the last call to BeginTOken).
int	getBeginOffset()
int	getColumn() Deprecated.
int	getEndColumn() Returns the column number of the last character for current token (being matched after the last call to BeginTOken).
int	getEndLine() Returns the line number of the last character for current token (being matched after the last call to BeginTOken).
int	getEndOffset()
java.lang.String	GetImage() Returns a string made up of characters from the marked token beginning to the current buffer position.
int	getLine() Deprecated.
char[]	GetSuffix(int len) Returns an array of characters that make up the suffix of length 'len' for the currently matched token.
char	readChar() Returns the next character from the selected input.
void	ReInit(java.io.InputStream dstream, int startline, int startcolumn)
void	ReInit(java.io.InputStream dstream, int startline, int startcolumn, int buffersize)
void	ReInit(java.io.Reader dstream, int startline, int startcolumn)
void	ReInit(java.io.Reader dstream, int startline, int startcolumn, int buffersize)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

staticFlag

public static final boolean staticFlag

See Also:

Constant Field Values

bufpos

public int bufpos

Constructor Detail

UCode_CharStream

public UCode_CharStream(java.io.Reader dstream,
                        int startline,
                        int startcolumn,
                        int buffersize)

UCode_CharStream

public UCode_CharStream(java.io.Reader dstream,
                        int startline,
                        int startcolumn)

UCode_CharStream

public UCode_CharStream(java.io.InputStream dstream,
                        int startline,
                        int startcolumn,
                        int buffersize)

UCode_CharStream

public UCode_CharStream(java.io.InputStream dstream,
                        int startline,
                        int startcolumn)

Method Detail

BeginToken

public char BeginToken()
                throws java.io.IOException

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.

Throws:

java.io.IOException

readChar

public final char readChar()
                    throws java.io.IOException

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.

Throws:

java.io.IOException

getColumn

@Deprecated
public final int getColumn()

Deprecated.

Returns the column position of the character last read.

See Also:

getEndColumn()

getLine

@Deprecated
public final int getLine()

Deprecated.

Returns the line number of the character last read.

See Also:

getEndLine()

getEndColumn

public final int getEndColumn()

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

getEndLine

public final int getEndLine()

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

getBeginColumn

public final int getBeginColumn()

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

getBeginLine

public final int getBeginLine()

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

getBeginOffset

public final int getBeginOffset()

getEndOffset

public final int getEndOffset()

backup

public final void backup(int amount)

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.

ReInit

public void ReInit(java.io.Reader dstream,
                   int startline,
                   int startcolumn,
                   int buffersize)

ReInit

public void ReInit(java.io.Reader dstream,
                   int startline,
                   int startcolumn)

ReInit

public void ReInit(java.io.InputStream dstream,
                   int startline,
                   int startcolumn,
                   int buffersize)

ReInit

public void ReInit(java.io.InputStream dstream,
                   int startline,
                   int startcolumn)

GetImage

public final java.lang.String 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.

GetSuffix

public final char[] GetSuffix(int len)

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(); }

Done

public void 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.

adjustBeginLineColumn

public void adjustBeginLineColumn(int newLine,
                                  int newCol)

Method to adjust line and column numbers for the start of a token.