sdsu.io
Class UnicodeReader

java.lang.Object
  |
  +--java.io.Reader
        |
        +--java.io.FilterReader
              |
              +--sdsu.io.UnicodeReader

public class UnicodeReader

extends java.io.FilterReader

This class provides a way of getting interpreted Unicode input from a reader. ASCII is a subset of Unicode. ASCII characters are read correctly. The standard Java library doesn't provide any way of reading things like integers from standard input. This functionality is nice to have for interactive programs.

Version:

0.9 14 Sept 1997

Author:

Andrew Scherpbier (andrew@sdsu.edu), Roger Whitney (whitney@cs.sdsu.edu)

Constructor Summary

UnicodeReader(java.io.InputStream input)
Creates a new UnicodeReader.

UnicodeReader(java.io.Reader input)
Creates a new UnicodeReader.

Method Summary

boolean	bad() Deprecated.
boolean	eof() Determines if stream is has reach end of file.
void	flushLine() Causes the next I/O operation to start at the beginning of the next input line.
boolean	hadEof() Determines if reach end of file in a previous read.
int	read(char[] b) Reads data into an array of chars.
int	read(char[] b, int off, int len) Reads data into an array of chars.
boolean	readBoolean() Reads an ASCII boolean value.
char	readChar() Read an ASCII character and convert it into the internal char format.
double	readDouble() Reads an ASCII decimal floating point number.
float	readFloat() Reads an ASCII decimal floating point number.
void	readFully(char[] b) Reads chars, blocking until all chars are read.
void	readFully(char[] b, int off, int len) Reads chars, blocking until all chars are read.
int	readInt() Reads an ASCII decimal integer.
java.lang.String	readLine() Reads in a line that has been terminated by a \n, \r, \r\n or EOF.
long	readLong() Reads an ASCII decimal long.
short	readShort() Reads an ASCII decimal short.
int	readUnsignedShort() Reads an ASCII decimal unsigned short.
java.lang.String	readWord() Reads a word.
int	skipChars(int n) Skips chars, block until all chars are skipped.

Methods inherited from class java.io.FilterReader

close, mark, markSupported, read, ready, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

UnicodeReader

public UnicodeReader(java.io.InputStream input)

Creates a new UnicodeReader.

Parameters:

input - the input stream which to read from.

UnicodeReader

public UnicodeReader(java.io.Reader input)

Creates a new UnicodeReader.

Parameters:

input - the input reader

Method Detail

bad

public boolean bad()

Deprecated.

Do not use. This method no longer does anything. Always returns false.

hadEof

public boolean hadEof()
               throws java.io.IOException

Determines if reach end of file in a previous read. This differs from eof() in in that eof() will indicate end of file if only white space remains. This function only indicates if you actually reached end of file an a prevoius read. If only whitespace remains and you use readInt (readDouble, etc.) an exception will be thrown. Use this method to detect end of file only if direct access to the white space between tokens is important to your program and you handle the case of a file ending in white space properly.

Returns:

true if end of file was reached.

See Also:

eof()

eof

public boolean eof()
            throws java.io.IOException

Determines if stream is has reach end of file. Consumes white space up to next token. If your program needs that white space between tokens use hadEof() instead. eof() is the prefered way to detect end of file.

Returns:

true if end of file was reached or if only white space remained in the stream.

See Also:

hadEof()

read

public int read(char[] b)
         throws java.io.IOException

Reads data into an array of chars. This method blocks until some input is available.

Parameters:

b - the buffer into which the data is read.

Returns:

the actual number of chars read. -1 is returned when the end of the stream is reached. (In this case, the eof() member will return true.)

Throws:

java.io.IOException - If an I/O error has occurred.

Overrides:

read in class java.io.Reader

read

public int read(char[] b,
                int off,
                int len)
         throws java.io.IOException

Reads data into an array of chars. This method blocks until some input is available.

Parameters:

b - the buffer into which the data is read.

off - the start offset of the data

len - the maximum number of chars read

Returns:

the actual number of chars read. -1 is returned when the end of the stream is reached. (In this case, the eof() member will return true.)

Throws:

java.io.IOException - If an I/O error has occurred.

Overrides:

read in class java.io.FilterReader

readFully

public void readFully(char[] b)
               throws java.io.IOException

Reads chars, blocking until all chars are read. If EOF is reached, the eof() member will return true.

Parameters:

b - the buffer into which the data is read

Throws:

java.io.IOException - If an I/O error has occurred.

readFully

public void readFully(char[] b,
                      int off,
                      int len)
               throws java.io.IOException

Reads chars, blocking until all chars are read. If EOF is reached, the eof() member will return true.

Parameters:

b - the buffer into which the data is read

off - the start offset of the data

len - the maximum number of chars read

Throws:

java.io.IOException - If an I/O error has occurred.

skipChars

public int skipChars(int n)
              throws java.io.IOException

Skips chars, block until all chars are skipped.

Parameters:

n - the number of chars to be skipped

Returns:

the actual number of chars skipped.

Throws:

java.io.IOException - If an I/O error has occurred.

readBoolean

public boolean readBoolean()
                    throws java.io.IOException

Reads an ASCII boolean value. It reads a word and determines if it represents true or false. Possible values are: true and false. The comparison is case insensitive. The eof() method will return true after this method has attempted to read beyond the end of file.

Returns:

the boolean.

Throws:

java.io.IOException - If an I/O error has occurred.

java.lang.NumberFormatException - If the next token in the input stream is not a valid boolean.

readShort

public short readShort()
                throws java.io.IOException

Reads an ASCII decimal short. Shorts can be preceded by optional whitespace. whitespace is defined as SPACE, TAB, CR, or NL. The eof() method will return true after this method has attempted to read beyond the end of file.

Returns:

the short.

Throws:

java.io.IOException - If an I/O error has occurred.

See Also:

readUnsignedShort

public int readUnsignedShort()
                      throws java.io.IOException

Reads an ASCII decimal unsigned short. Unsigned shorts can be preceded by optional whitespace. whitespace is defined as SPACE, TAB, CR, or NL.

Returns:

an int representing the unsigned short.

Throws:

java.io.IOException - If an I/O error has occurred.

See Also:

readChar

public char readChar()
              throws java.io.IOException

Read an ASCII character and convert it into the internal char format. The eof() method will return true after this method has attempted to read beyond the end of file.

Returns:

the character.

Throws:

java.io.IOException - If an I/O error occurred.

readInt

public int readInt()
            throws java.io.IOException

Reads an ASCII decimal integer. Integers can be preceded by optional whitespace. whitespace is defined as SPACE, TAB, CR, or NL. The eof() method will return true after this method has attempted to read beyond the end of file.

Returns:

the integer.

Throws:

java.io.IOException - If an I/O error has occurred.

readLong

public long readLong()
              throws java.io.IOException

Reads an ASCII decimal long. Longs can be preceded by optional whitespace. whitespace is defined as SPACE, TAB, CR, or NL. The eof() method will return true after this method has attempted to read beyond the end of file.

Returns:

the long or 0 when EOF was reached.

Throws:

java.io.IOException - If an I/O error has occurred.

readFloat

public float readFloat()
                throws java.io.IOException

Reads an ASCII decimal floating point number. A floating point number is defined as follows:

• an optional '-' to make the number negative
• 0 or more digits
• an optional period follows by more digits
• an optional 'e' or 'E' to introduce the exponent
  • an optional '-' to make the exponent negative
  • digits making up the exponent

Floats can be preceded by optional whitespace. whitespace is defined as SPACE, TAB, CR, or NL.
If an error on the format of the number is found, the bad() member will return true.

Returns:

the float.

Throws:

java.io.IOException - If an I/O error has occurred.

readDouble

public double readDouble()
                  throws java.io.IOException

Reads an ASCII decimal floating point number. A floating point number is defined as follows:

• an optional '-' to make the number negative
• 0 or more digits
• an optional period follows by more digits
• an optional 'e' or 'E' to introduce the exponent
  • an optional '-' to make the exponent negative
  • digits making up the exponent

Doubles can be preceded by optional whitespace. whitespace is defined as SPACE, TAB, CR, or NL.
If an error on the format of the number is found, the bad() member will return true.

Returns:

the double.

Throws:

java.io.IOException - If an I/O error has occurred.

readLine

public java.lang.String readLine()
                          throws java.io.IOException

Reads in a line that has been terminated by a \n, \r, \r\n or EOF. The eof() method will return true if the read attempted to go beyond the end of file. The terminating line characters will not be part of the String that is returned.

Returns:

a String copy of the line or null if nothing more could be read.

Throws:

java.io.IOException - If an I/O error has occurred.

readWord

public java.lang.String readWord()
                          throws java.io.IOException

Reads a word. A word is a string of characters deliminated by whitespace or EOF. A word can be preceded by optional whitespace characters. Whitespace is defined as SPACE, TAB, CR, or NL.

Returns:

the word or null if EOF reached.

Throws:

java.io.IOException - If an I/O error has occurred.

flushLine

public void flushLine()
               throws java.io.IOException

Causes the next I/O operation to start at the beginning of the next input line. Lines are delimited by either cr, cr lf, or lf.

Throws:

java.io.IOException - If an I/O error has occurred.