Debug

java.lang.Object
- Debug

```
public class Debug
extends java.lang.Object
```
In writing your code, you may be tempted to use System.out.printf() to determine what is happening. As an alternative, the method Debug.printf() is provided. The nice thing about Debug.printf() in comparison to System.out.printf() is that Debug.printf() only prints when debug is turn on. You can turn debug on and off by setting the staic variable debugLevel to non-zero. This is normally done by a command line parameter to the main() of your program. This module allows you to write debug code, but not need to change your program in any way before turning it in. If you use System.out.printf() you MUST either comment out the lines or remove them before you submit your code for grading. This is a simple alternative to the many logging packages that have more advanced capabilities. See this page for examples.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`debugLevel` A variable controlling how much debug output is produced.
`static java.lang.String`	`prefix` Define prefix of flag to turn on debugging
`private static java.io.PrintStream`	`ps` A variable to allow debug output to go someplace other than `System.err`.

Constructor Summary

Constructors
Modifier Constructor and Description

private Debug()
Purely static, no instances may be created

Constructors
Modifier	Constructor and Description
`private`	`Debug()` Purely static, no instances may be created

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`close()` Close the output stream if it is not `System.err`.
`static java.lang.String`	`format(java.lang.String format, java.lang.Object... args)` An "extension" of `String.format()` to automatically convert arrays to Strings using the `Arrays.toString()` methods.
`static boolean`	`HERE()` Simple routine to print the fileName, lineNumber and methodName.
`static java.lang.String[]`	`init(java.lang.String[] args)` This routine will initialize the class from the arguments passed to `main()`.
`static boolean`	`printf(int level, java.lang.String format, java.lang.Object... args)` Print a message if the parameter `level` is less than or equal to `debugLevel`.
`static boolean`	`printf(java.lang.String format, java.lang.Object... args)` Print a message if the variable `Debug.debugLevel` is non-zero.
`private static void`	`printIt(java.lang.String format, java.lang.Object... args)` Print the output prefix "DEBUG fileName[lineNumber] methodName"
`static void`	`toFile(java.lang.String fileName)` Send debugging output to a file.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - prefix
```
public static final java.lang.String prefix
```
    Define prefix of flag to turn on debugging
    
    See Also:
    
    Constant Field Values
  - debugLevel
```
public static int debugLevel
```
    A variable controlling how much debug output is produced. A value of 0 means no output. This is normally set by your program's main() by a command line argument. With the Debug.lDebug() you can vary the amount of output from none, to a lot.
  - ps
```
private static java.io.PrintStream ps
```
    A variable to allow debug output to go someplace other than System.err. See the toFile(), close() methods. Default to System.err.
- Constructor Detail
  - Debug
```
private Debug()
```
    Purely static, no instances may be created
- Method Detail
  - init
```
public static java.lang.String[] init(java.lang.String[] args)
```
    This routine will initialize the class from the arguments passed to main(). If the first argument is, or starts with -debug the class is initialized and the first parameter is removed from the args. The first parameter may have one of three forms:
    1. -debug - turn on debugging at level 1
    2. -debugValue - set debugging level to Value (e.g. -debug5)
    3. -debugValue@fileName set debugging level to Value and send debugging output to the file fileName. If you use this option, the file must b closed using Debug.close().
    NOTE: If any initialization fails, an error message is printed and the program terminates.
    Parameters:
    
    args - the array of arguments passed to main()
    
    Returns:
    
    args with the first value removed (if appropriate)
  - printIt
```
private static void printIt(java.lang.String format,
                            java.lang.Object... args)
```
    Print the output prefix "DEBUG fileName[lineNumber] methodName"
    
    Parameters:
    
    format - the format string for the output
    
    args - arguments for the format string (variable number)
  - format
```
public static java.lang.String format(java.lang.String format,
                                      java.lang.Object... args)
```
    An "extension" of String.format() to automatically convert arrays to Strings using the Arrays.toString() methods. Arrays of arrays are also handled. The argument list is exactly the same as that of String.format(), so any of the features of that code may be used. If there is only a single argument after the format and if that argument is an array, cast it to an Object using ((Object))
    
    Parameters:
    
    format - the format string for the output (use %s for arrays)
    
    args - arguments for the format string (variable number)
    
    Returns:
    
    the formatted string with all array objects expanded
  - HERE
```
public static boolean HERE()
```
    Simple routine to print the fileName, lineNumber and methodName. Used for quick debugging to see if your code even gets to a particular place.
    
    Returns:
    
    always returns true. Allows you to "abuse" the assert statement for higher performance.
  - printf
```
public static boolean printf(java.lang.String format,
                             java.lang.Object... args)
```
    Print a message if the variable Debug.debugLevel is non-zero. The argument list is exactly the same as that of String.format(), so any of the features of that code may be used. See the documentation of Debug.format() for details on printing arrays.
    
    Parameters:
    
    format - the format string for the output
    
    args - arguments for the format string (variable number)
    
    Returns:
    
    always returns true. Allows you to "abuse" the assert statement for higher performance.
  - printf
```
public static boolean printf(int level,
                             java.lang.String format,
                             java.lang.Object... args)
```
    Print a message if the parameter level is less than or equal to debugLevel. The argument list following level is exactly the same as that of String.format(), so any of the features of that code may be used. See the documentation of Debug.format() for details on printing arrays.
    
    Parameters:
    
    level - controls whether message is printed or not
    
    format - the format string for the output
    
    args - arguments for the format string (variable number)
    
    Returns:
    
    always returns true. Allows you to "abuse" the assert statement for higher performance.
  - toFile
```
public static void toFile(java.lang.String fileName)
                   throws java.io.FileNotFoundException
```
    Send debugging output to a file. This may be called from the init() method. If you send output to a file, be sure and close it with Debug.close().
    
    Parameters:
    
    fileName - name of the file to send output to
    
    Throws:
    
    java.io.FileNotFoundException
  - close
```
public static void close()
```
    Close the output stream if it is not System.err. For use in conjunction with toFile() or initialization of output to a file in Debug.init().

Class Debug

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

prefix

debugLevel

ps

Constructor Detail

Debug

Method Detail

init

printIt

format

HERE

printf

printf

toFile

close