Class sdsu.io.ASCIIInputStream

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Class sdsu.io.ASCIIInputStream

java.lang.Object
   |
   +----java.io.InputStream
           |
           +----java.io.FilterInputStream
                   |
                   +----sdsu.io.ASCIIInputStream

public class ASCIIInputStream
extends FilterInputStream
implements DataInput

This class provides a way of getting interpreted ASCII input from a stream. 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.

Author:: Andrew Scherpbier (andrew@sdsu.edu)

ASCIIInputStream(InputStream): Creates a new ASCIIInputStream.

bad(): Determines if a previous ASCII I/O operation caused an error.
eof(): Determines if a previous ASCII I/O operation caught End Of File.
flushLine(): Causes the next I/O operation to start at the beginning of the next input line.
read(byte[]): Reads data into an array of bytes.
read(byte[], int, int): Reads data into an array of bytes.
readBoolean(): Reads an ASCII boolean value.
readByte(): Reads a single byte.
readChar(): Read an ASCII character and convert it into the internal char format.
readDouble(): Reads an ASCII decimal floating point number.
readFloat(): Reads an ASCII decimal floating point number.
readFully(byte[]): Reads bytes, blocking until all bytes are read.
readFully(byte[], int, int): Reads bytes, blocking until all bytes are read.
readInt(): Reads an ASCII decimal integer.
readLine(): Reads in a line that has been terminated by a \n, \r, \r\n or EOF.
readLong(): Reads an ASCII decimal long.
readShort(): Reads an ASCII decimal short.
readUnsignedByte(): Reads a single unsigned byte.
readUnsignedShort(): Reads an ASCII decimal unsigned short.
readUTF(): Does nothing.
readWord(): Reads a word.
skipBytes(int): Skips bytes, block until all bytes are skipped.

ASCIIInputStream

  public ASCIIInputStream(InputStream stream)

Creates a new ASCIIInputStream.

bad

  public boolean bad()

Determines if a previous ASCII I/O operation caused an error. Errors can occur in the reading of numbers.

Returns:: true if there was an error.
See Also:: eof

eof

  public boolean eof()

Determines if a previous ASCII I/O operation caught End Of File.

Returns:: true if end of file was reached.

read

  public int read(byte b[]) throws IOException

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

Parameters:: b - the buffer into which the data is read.
Returns:: the actual number of bytes read. -1 is returned when the end of the stream is reached. (In this case, the eof() member will return true.)
Throws: IOException: If an I/O error has occurred.
Overrides:: read in class FilterInputStream

read

  public int read(byte b[],
                  int off,
                  int len) throws IOException

Reads data into an array of bytes. 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 bytes read
Returns:: the actual number of bytes read. -1 is returned when the end of the stream is reached. (In this case, the eof() member will return true.)
Throws: IOException: If an I/O error has occurred.
Overrides:: read in class FilterInputStream

readFully

  public void readFully(byte b[]) throws IOException

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

Parameters:: b - the buffer into which the data is read
Throws: IOException: If an I/O error has occurred.

readFully

  public void readFully(byte b[],
                        int off,
                        int len) throws IOException

Reads bytes, blocking until all bytes 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 bytes read
Throws: IOException: If an I/O error has occurred.

skipBytes

  public int skipBytes(int n) throws IOException

Skips bytes, block until all bytes are skipped.

Parameters:: n - the number of bytes to be skipped
Returns:: the actual number of bytes skipped.
Throws: IOException: If an I/O error has occurred.

readBoolean

  public boolean readBoolean() throws IOException

Reads an ASCII boolean value. It reads a word and determines if it represents true or false. Possible values for false are:

false
no
0

All other words are considered true. The eof() method will return true after this method has attempted to read beyond the end of file.

Returns:: the boolean.
Throws: IOException: If an I/O error has occurred.

readByte

  public byte readByte() throws IOException

Reads a single byte. The eof() method will return true after this method has attempted to read beyond the end of file.

Returns:: the byte.
Throws: IOException: If an I/O error has occurred.

readUnsignedByte

  public int readUnsignedByte() throws IOException

Reads a single unsigned byte. This is virually the same as readChar(), except that the return value is an int.

Returns:: an int representing the unsigned byte.
Throws: IOException: If an I/O error has occurred.
See Also:: readChar

readShort

  public short readShort() throws 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: IOException: If an I/O error has occurred.
See Also:: ASCIIInputStream@readInt

readUnsignedShort

  public int readUnsignedShort() throws 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: IOException: If an I/O error has occurred.
See Also:: ASCIIInputStream@readInt

readChar

  public char readChar() throws 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: IOException: If an I/O error occurred.

readInt

  public int readInt() throws 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: IOException: If an I/O error has occurred.

readLong

  public long readLong() throws 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: IOException: If an I/O error has occurred.

readFloat

  public float readFloat() throws 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: IOException: If an I/O error has occurred.

readDouble

  public double readDouble() throws 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: IOException: If an I/O error has occurred.

readLine

  public String readLine() throws 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: IOException: If an I/O error has occurred.

readUTF

  public String readUTF() throws IOException

Does nothing. Do not use.

readWord

  public String readWord() throws 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: IOException: If an I/O error has occurred.

flushLine

  public void flushLine() throws 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: IOException: If an I/O error has occurred.

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