* util.java * * Useful Java utilities for use in GaTech's Introduction to Programming. * Routines include input from standard in, and assertions. * * JDK Version: JDK1.0.2 * Revisions: 1.54 September 22, 1997, Khai Truong (khai@cc.gatech.edu) * Revised readLine() to return remaining text on current * line of input (if any exists, else reads next line). * 1.53 July 2, 1997, Khai Truong (khai@cc.gatech.edu) * Fixed erroneous calls in various read (binary) * routines. * Revised some incorrect Javadoc documentation. * 1.52 May 24, 1997, Jason Hong (hong@cc.gatech.edu) * Revised some incorrect Javadoc documentation * Removed some Javadoc documentation-start markers * for methods using DataInputStream to reduce amount * of information a student will have to search thru. * 1.51 May 19, 1997 Jason Hong and Larry Hsieh * Added copyright information * Added debug() routine * 1.42 February 26, 1997, Jason Hong (hong@cc.gatech.edu) * Updated documentation, added example usage * 1.41 February 19, 1997, Jason Hong (hong@cc.gatech.edu) * Added readlnWord() method * 1.4 January 6, 1997, Jason Hong (hong@cc.gatech.edu) * Added readWord() method (Thanks Khai and Larry) * Revised documentation for javadoc * Added binary and non-binary reads * 1.3 November 28, 1996, Jason Hong (hong@cc.gatech.edu) * Separated file routines into another class (AbstractFile) * Made all methods final for optimization * Revised documentation for javadoc * Renamed some variables for consistency * Modified error messages * Added error codes * Optimized ASSERT() method * Added another ASSERT() method * Added both ABORT() methods * 1.2 October 15, 1996, Jason Hong (hong@cc.gatech.edu) * Added Larry Hsieh's input and output routines for files * 1.1 October 10, 1996, Jason Hong (hong@cc.gatech.edu) * Added some input and output routines for stdin * 1.0 October 01, 1996, Jason Hong (hong@cc.gatech.edu) * Created the util.java for cs1502 ** * *
* Example Usage: *
* Given the input: * ABC * D E F * GHI ** *
*
* public static void main(String[] argv)
* {
* Character characterRead;
* characterRead = util.readCharacter(); // reads in 'A'
* characterRead = util.readCharacter(); // reads in 'B'
* characterRead = util.readCharacter(); // reads in 'C'
* characterRead = util.readCharacter(); // reads in 'D'
* characterRead = util.readlnCharacter(); // reads in 'E', goes to next line
* characterRead = util.readCharacter(); // reads in 'G'
* characterRead = util.readlnCharacter(); // reads in 'H', goes to next line
* characterRead = util.readCharacter(); // returns null
* }
*
*
* * Example of what not to do: *
* Given the input: * A ** *
*
* public static void main(String[] argv)
* {
* char chInput;
*
* //// DON'T DO THIS!!!
* chInput = util.readCharacter().charValue(); // read's in 'A'
* chInput = util.readCharacter().charValue(); // NullPointerException
* }
*
*
* The reason you should not do this is because util.readCharacter()
* can return a null reference (at which point you cannot call method
* charValue().
*
* * Here is how to read until end of file: *
* Character charInput;
* char chInput;
*
* while ( (charInput = util.readCharacter()) != null )
* {
* chInput = charInput.charValue();
*
* //// DO STUFF WITH THE INPUT HERE
* }
*
*
*
* @author Jason Hong
* @author Larry Hsieh
* @author Khai Truong
* @version Version 1.54, September 22, 1997
*/
class util
{
//===========================================================================
// CONSTANTS
//===========================================================================
//// The current version of this file
static final double VERSION = 1.54;
//// Should ASSERT be compiled or not?
static final boolean COMPILE_ASSERT = true;
//// Is this for an Applet or not?
static final boolean COMPILE_APPLET = false;
//// Error return values
static final int ERR_GENERAL = 1; // A general error
static final int ERR_ASSERT = 2; // An ASSERT failure
//===========================================================================
//===========================================================================
// NONLOCAL VARIABLES
//===========================================================================
//// For reading data from standard in (stdin)
private static DataInputStream
stdinDataInputStream = new DataInputStream(System.in);
//// For reading in words of data (Strings of chars, not words of data)
private static StringTokenizer strtokLine = new StringTokenizer("");
//// To clear out the StringTokenizer strtokLine
private static final StringTokenizer
strtokEmptyLine = new StringTokenizer("");
//===========================================================================
//===========================================================================
// DEBUG MODE METHODS
//===========================================================================
/**
* Allows the ability to redirect standard input to a input file
* called "input.txt" . This is a workaround the Symantec Cafe (v1.51)
* inability to use standard input.
*
* * If "input.txt" exists stdinDataInputStream is redirected from * standard input. If file doesn't exists, a warning message is * displayed and sdinDataInputStream remains standard input. * *
* Note: This allows for scripted input and the ability to debug
* since I/O is not possible in debug mode.
*/
final public static void debug()
{
try
{
stdinDataInputStream = new
DataInputStream(new FileInputStream("input.txt"));
} // of try
catch (FileNotFoundException e)
{
System.out.println("Unable to located input.txt");
System.out.println("Cannot enter debug mode!");
System.out.println("Using regular standard input");
} // of catch
} // of debug
//===========================================================================
//===========================================================================
// VERIFICATION METHODS
//===========================================================================
/**
* Print out an error Message and exit immediately.
* The program will exit with value ERR_GENERAL after printing
* the error message passed in.
*
* @param strErrorMessage is the error message to print out.
*/
final public static void ABORT(String strErrorMessage)
{
ABORT(strErrorMessage, ERR_GENERAL);
} // of ABORT
//===========================================================================
/**
* Print out an error Message and exit immediately with a return value.
* The program will exit with the value passed in after printing
* the error message passed in.
*
* @param strErrorMessage is the error message to print out.
* @param iErrorValue is the error value to return on exit.
*/
final public static void ABORT(String strErrorMessage, int iErrorValue)
{
//// forces buffered output to be printed
System.out.flush();
//// print out the error message
System.err.println("\n" + strErrorMessage);
new Throwable().printStackTrace();
System.err.println("\nAborting program\n");
System.err.flush();
//// Applets cannot call System.exit(), so throw a runtime
//// exception instead (which methods do not explicitly have to
//// declare to catch)
if (COMPILE_APPLET)
throw new RuntimeException(strErrorMessage);
else
System.exit(iErrorValue);
} // of ABORT
//===========================================================================
/**
* Validate a predicate.
* If predicate evaluates to true, then the function call passes through
* with no side effects. If the predicate is false, then
* stack will be printed out, and the program will exit immediately.
*
* Note: Recompile util.java with the COMPILE_ASSERT flag set to false * in order to compile without ASSERT statements. *
* Note: Instead of calling ABORT, you can tailor this to your needs. * This is just one implementation of ASSERT. The default * action on a failed ASSERT() here is to exit. You may * choose to do something more useful, like save the program, * go back to a known good state, put in a value that is * harmless, etc. *
* Sample: util.ASSERT(iValue > 0); * util.ASSERT(cValue == 'a' || cValue == 'A'); * util.ASSERT(iValue++) is WRONG because of side effects * * @param predicate is an expression that evaluates to a boolean to test. * You should not pass in an expression with side effects. */ final public static void ASSERT(boolean predicate) { // if COMPILE_ASSERT if false, the optimizer will remove this if (COMPILE_ASSERT == true) { if (predicate == false) ABORT("Assertion error", ERR_ASSERT); } // of if COMPILE_ASSERT } // of ASSERT //=========================================================================== /** * Validate a predicate. *
* Note: See the other ASSERT method. * * @param predicate is an expression that evaluates to a boolean to test. * You should not pass in an expression with side effects. * @param strErrorMessage is the error message to print out if the * assertion should fail. */ final public static void ASSERT(boolean predicate, String strErrorMessage) { // if COMPILE_ASSERT if false, the optimizer will remove this if (COMPILE_ASSERT == true) { if (predicate == false) ABORT("Assertion error:" + strErrorMessage, ERR_ASSERT); } // of if COMPILE_ASSERT } // of ASSERT //=========================================================================== //=========================================================================== // MISCELLANEOUS INPUT METHODS //=========================================================================== /** * Clear the StringTokenizer to end of line. * This makes it read from the next line the next time a read is done. */ private static void clearToEndOfLine() { strtokLine = new StringTokenizer(""); } // of clearToEndOfLine //=========================================================================== //=========================================================================== // BYTE INPUT METHODS //=========================================================================== /** * Read in a byte from standard input. *
* Note: This needs to be fixed to return a Byte object once JVM 1.1
* comes out.
*
* @return Returns the byte read in if successful (as a Character).
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Character readByte()
{
return (readByte(stdinDataInputStream));
} // of readByte
//===========================================================================
/**
* Read in a byte from standard input and ignore the rest of the line.
*
* Note: This needs to be fixed to return a Byte object once JVM 1.1
* comes out.
*
* @return Returns the byte read in if successful (as a Character).
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Character readlnByte()
{
return (readlnByte(stdinDataInputStream));
} // of readlnByte
//===========================================================================
/*
* Read in a byte from a DataInputStream.
*
* Note: This needs to be fixed to return a Byte object once JVM 1.1
* comes out
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the byte read in if successful (as a Character).
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final protected static Character readByte(DataInputStream dataInputStream)
{
byte byteInput = 0;
ASSERT(dataInputStream != null, "Input stream is null");
try
{
byteInput = dataInputStream.readByte();
} // of try
catch (EOFException e)
{
return(null);
} // of catch
catch (IOException e)
{
ABORT("Read failure\n" + e);
} // of catch
// otherwise, return the character read in
return(new Character((char) byteInput));
} // of readByte
//===========================================================================
/*
* Read in a byte from a DataInputStream and ignore the rest of the line.
*
* Note: This needs to be fixed to return a Byte object once JVM 1.1
* comes out
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the byte read in if successful (as a Character).
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final protected static Character readlnByte(DataInputStream dataInputStream)
{
Character charReturnByte = readByte(dataInputStream);
readLine(dataInputStream);
return(charReturnByte);
} // of readlnByte
//===========================================================================
//===========================================================================
// CHARACTER INPUT METHODS
//===========================================================================
/**
* Read in an ASCII character from standard input (ignores carriage
* returns and newlines).
*
* Note: Does not read Unicode.
*
* @return Returns the character read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Character readCharacter()
{
return (readCharacter(stdinDataInputStream));
} // of readCharacter
//===========================================================================
/**
* Read in an ASCII character from standard input (ignores
* carriage returns and newlines).
*
* Note: Does not read Unicode.
*
* @return Returns the character read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Character readlnCharacter()
{
return (readlnCharacter(stdinDataInputStream));
} // of readlnCharacter
//===========================================================================
/*
* Read in an ASCII character from a DataInputStream (ignores
* whitespace) and ignore the rest of the line.
*
* Note: Does not read Unicode.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the character read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final protected static Character
readCharacter(DataInputStream dataInputStream)
{
char chInput = '\u0000';
ASSERT(dataInputStream != null, "Input stream is null");
try
{
do
{
chInput = (char) dataInputStream.readByte();
} while (Character.isSpace(chInput));
} // of try
catch (EOFException e)
{
return(null);
} // of catch
catch (IOException e)
{
ABORT("Read failure\n" + e);
} // of catch
// Return the character read in
return(new Character(chInput));
} // of readCharacter
//===========================================================================
/*
* Read in a character from a DataInputStream (ignores newlines).
* All input after the first character is discarded.
*
* Note: Does not read Unicode.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the character read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Character
readlnCharacter(DataInputStream dataInputStream)
{
Character charReturn = readCharacter(dataInputStream);
readLine(dataInputStream);
return(charReturn);
} // of readlnCharacter
//===========================================================================
//===========================================================================
// INTEGER INPUT METHODS
//===========================================================================
/**
* Read in an Integer from standard input.
*
* @return Returns the Integer read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Integer readInteger()
{
return (readInteger(stdinDataInputStream));
} // of readInteger
//===========================================================================
/**
* Read in an Integer from standard input and ignore the rest of the line.
*
* @return Returns the Integer read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Integer readlnInteger()
{
return (readlnInteger(stdinDataInputStream));
} // of readlnInteger
//===========================================================================
/*
* Read in an Integer from specified DataInputStream.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Integer read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Integer readInteger(DataInputStream dataInputStream)
{
String strInput;
strInput = readWord(dataInputStream);
if (strInput == null)
return(null);
else
return(new Integer(strInput));
} // of readInteger
//===========================================================================
/*
* Read in an Integer from a DataInputStream and ignore the rest of the line.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Integer read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Integer readlnInteger(DataInputStream dataInputStream)
{
Integer intReturn = readInteger(dataInputStream);
clearToEndOfLine();
return(intReturn);
} // of readlnInteger
//===========================================================================
//===========================================================================
// BINARY INTEGER INPUT METHODS
//===========================================================================
/**
* Read in an Integer from standard input (binary).
*
* @return Returns the Integer read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Integer readBinaryInteger()
{
return (readBinaryInteger(stdinDataInputStream));
} // of readBinaryInteger
//===========================================================================
/**
* Read in an Integer from standard input (binary) and ignore the
* rest of the line.
*
* @return Returns the Integer read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Integer readlnBinaryInteger()
{
return (readlnBinaryInteger(stdinDataInputStream));
} // of readlnBinaryInteger
//===========================================================================
/*
* Read in an Integer from specified DataInputStream (binary).
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Integer read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Integer
readBinaryInteger(DataInputStream dataInputStream)
{
int iInput = 0;
ASSERT(dataInputStream != null, "Input stream is null");
try
{
iInput = dataInputStream.readInt();
} // of try
catch (EOFException e)
{
return(null);
} // of catch
catch (IOException e)
{
ABORT("Read failure\n" + e);
} // of catch
// Return the character read in
return(new Integer(iInput));
} // of readBinaryInteger
//===========================================================================
/*
* Read in an Integer from specified DataInputStream (binary) and ignore
* the rest of the line.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Integer read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Integer
readlnBinaryInteger(DataInputStream dataInputStream)
{
Integer intReturn = readBinaryInteger(dataInputStream);
readLine(dataInputStream);
return(intReturn);
} // of readlnBinaryInteger
//===========================================================================
//===========================================================================
// FLOAT INPUT METHODS
//===========================================================================
/**
* Read in a Float from standard input.
*
* @return Returns the Float read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Float readFloat()
{
return (readFloat(stdinDataInputStream));
} // of readFloat
//===========================================================================
/**
* Read in a Float from standard input and ignore the rest of the line.
*
* @return Returns the Float read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Float readlnFloat()
{
return (readlnFloat(stdinDataInputStream));
} // of readlnFloat
//===========================================================================
/*
* Read in a Float from a DataInputStream.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Float read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Float readFloat(DataInputStream dataInputStream)
{
String strInput;
strInput = readWord(dataInputStream);
if (strInput == null)
return(null);
else
return(new Float(strInput));
} // of readFloat
//===========================================================================
/*
* Read in a Float from a DataInputStream and ignore the rest of the line.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Float read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Float readlnFloat(DataInputStream dataInputStream)
{
Float fReturn = readFloat(dataInputStream);
clearToEndOfLine();
return(fReturn);
} // of readlnFloat
//===========================================================================
//===========================================================================
// BINARY FLOAT INPUT METHODS
//===========================================================================
/**
* Read in a Float from standard input (binary).
*
* @return Returns the Float read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Float readBinaryFloat()
{
return (readBinaryFloat(stdinDataInputStream));
} // of readBinaryFloat
//===========================================================================
/**
* Read in a Float from standard input (binary) and ignore the rest
* of the line.
*
* @return Returns the Float read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Float readlnBinaryFloat()
{
return (readlnBinaryFloat(stdinDataInputStream));
} // of readlnBinaryFloat
//===========================================================================
/*
* Read in a Float from a DataInputStream (binary).
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Float read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Float readBinaryFloat(DataInputStream dataInputStream)
{
float fInput = 0;
ASSERT(dataInputStream != null, "Input stream is null");
try
{
fInput = dataInputStream.readFloat();
} // of try
catch (EOFException e)
{
return(null);
} // of catch
catch (IOException e)
{
ABORT("Read failure\n" + e);
} // of catch
// Return the character read in
return(new Float(fInput));
} // of readBinaryFloat
//===========================================================================
/*
* Read in a Float from a DataInputStream (binary) and ignore the rest
* of the line.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Float read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Float readlnBinaryFloat(DataInputStream dataInputStream)
{
Float fReturn = readBinaryFloat(dataInputStream);
readLine(dataInputStream);
return(fReturn);
} // of readlnBinaryFloat
//===========================================================================
//===========================================================================
// DOUBLE INPUT METHODS
//===========================================================================
/**
* Read in a Double from standard input.
*
* @return Returns the Double read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Double readDouble()
{
return (readDouble(stdinDataInputStream));
} // of readDouble
//===========================================================================
/**
* Read in a Double from standard input and ignore the rest of the line.
*
* @return Returns the Double read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Double readlnDouble()
{
return (readlnDouble(stdinDataInputStream));
} // of readlnDouble
//===========================================================================
/*
* Read in a Double from a DataInputStream.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Double read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Double readDouble(DataInputStream dataInputStream)
{
String strInput;
ASSERT(dataInputStream != null, "Input stream is null");
strInput = readWord(dataInputStream);
if (strInput == null)
return(null);
else
return(new Double(strInput));
} // of readDouble
//===========================================================================
/*
* Read in a Double from a DataInputStream and ignore the rest of the line.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Double read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Double readlnDouble(DataInputStream dataInputStream)
{
Double intReturn = readDouble(dataInputStream);
clearToEndOfLine();
return(intReturn);
} // of readlnDouble
//===========================================================================
//===========================================================================
// BINARY DOUBLE INPUT METHODS
//===========================================================================
/**
* Read in a Double from standard input (binary).
*
* @return Returns the Double read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Double readBinaryDouble()
{
return (readBinaryDouble(stdinDataInputStream));
} // of readBinaryDouble
//===========================================================================
/**
* Read in a Double from standard input (binary) and ignore the rest
* of the line.
*
* @return Returns the Double read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Double readlnBinaryDouble()
{
return (readlnBinaryDouble(stdinDataInputStream));
} // of readlnBinaryDouble
//===========================================================================
/*
* Read in a Double from a DataInputStream (binary).
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Double read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Double readBinaryDouble(DataInputStream dataInputStream)
{
double dInput = 0;
ASSERT(dataInputStream != null, "Input stream is null");
try
{
dInput = dataInputStream.readDouble();
} // of try
catch (EOFException e)
{
return(null);
} // of catch
catch (IOException e)
{
ABORT("Read failure\n" + e);
} // of catch
// Return the character read in
return(new Double(dInput));
} // of readBinaryDouble
//===========================================================================
/*
* Read in a Double from a DataInputStream (binary) and ignore the rest
* of the line.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the Double read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static Double
readlnBinaryDouble(DataInputStream dataInputStream)
{
Double dReturn = readBinaryDouble(dataInputStream);
readLine(dataInputStream);
return(dReturn);
} // of readlnBinaryDouble
//===========================================================================
//===========================================================================
// STRING INPUT METHODS
//===========================================================================
/**
* Read in a word (string of chars, not a word of data) from standard input
* and stay on the same line.
*
* @return Returns the String read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static String readWord()
{
return (readWord(stdinDataInputStream));
} // of readWord
//===========================================================================
/*
* Read in a word (string of chars, not a word of data) from a
* DataInputStream and stay on the same line.
*
* @param dataInputStream is a DataInputStream.
* @return Returns the String read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static String readWord(DataInputStream dataInputStream)
{
String strInput = new String();
ASSERT(dataInputStream != null, "Input stream is null");
ASSERT(strtokLine != null, "String tokenizer is a null reference");
//// Skip all blank lines
while (!strtokLine.hasMoreTokens())
{
//// See if there's still more data left on this line
try
{
// read in from stdin
// method readLine returns null if EOF
strInput = dataInputStream.readLine();
if (strInput == null)
return(null);
strtokLine = new StringTokenizer(strInput);
} // of try
catch (IOException e)
{
ABORT("Read failure\n" + e);
} // of catch
}
// otherwise, return the String
return(strtokLine.nextToken());
} // of readWord
//===========================================================================
/**
* Read in a word (string of chars, not a word of data) from standard input
* and go to the next line.
*
* @return Returns the String read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static String readlnWord()
{
return(readlnWord(stdinDataInputStream));
} // of readlnWord
//===========================================================================
/*
* Read in a word (string of chars, not a word of data) from a
* DataInputStream and go to the next line.
*
* @param dataInputStream is a DataInputStream already initialized.
* @return Returns the String read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static String readlnWord(DataInputStream dataInputStream)
{
String strReturn = readWord(dataInputStream);
clearToEndOfLine();
return(strReturn);
} // of readlnWord
//===========================================================================
/**
* Read in a line from standard input and go to the next line.
*
* @return Returns the String read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static String readLine()
{
return (readLine(stdinDataInputStream));
} // of readLine
//===========================================================================
/*
* Read in a line from a DataInputStream and go to the next line.
*
* @param dataInputStream is a DataInputStream.
* @return Returns the String read in if successful.
* Returns null if end of file has been reached.
* Exits program on a read exception (IOException).
*/
final public static String readLine(DataInputStream dataInputStream)
{
String strInput = new String();
ASSERT(dataInputStream != null, "Input stream is null");
ASSERT(strtokLine != null, "String tokenizer is a null reference");
if (strtokLine.hasMoreTokens())
strInput = strtokLine.nextToken("").trim();
if (strInput.length()<=0)
try
{
// read in from stdin
// method readLine returns null if EOF
strInput = dataInputStream.readLine();
} // of try
catch (IOException e)
{
ABORT("Read failure\n" + e);
} // of catch
// otherwise, return the String
clearToEndOfLine();
return(strInput);
} // of readline
//===========================================================================
//===========================================================================
// MAIN
//===========================================================================
/**
* Tells what version number this is.
*/
public static void main(String[] argv)
{
System.err.println("This class is not meant to be run.");
System.err.println("util.java version " + VERSION);
System.exit(1);
} // of main
//===========================================================================
} // of class util
//==============================================================================