CompareUtil (philib 0.12.0 API)

java.lang.Object
- ch.bind.philib.lang.CompareUtil

```
public abstract class CompareUtil
extends Object
```
Provides helper methods for object comparison.

Author:

Philipp Meinen

Constructor Summary

Constructors
Modifier Constructor and Description

protected CompareUtil()

Constructors
Modifier	Constructor and Description
`protected`	`CompareUtil()`

Method Summary

Methods
Modifier and Type	Method and Description
`static <T> int`	`compare(Comparable<T> a, T b)` A null-safe compare helper.
`static int`	`diff(boolean a, boolean b)` Helper for compareTo implementations. Boolean version which considers `false < true`
`static int`	`diff(byte a, byte b)` Helper for compareTo implementations. Byte version which masks the input values so that an unsigned comparison is performed.
`static int`	`diff(char a, char b)` Helper for compareTo implementations.
`static int`	`diff(double a, double b)` Helper for compareTo implementations.
`static int`	`diff(float a, float b)` Helper for compareTo implementations.
`static int`	`diff(int a, int b)` Helper for compareTo implementations.
`static int`	`diff(long a, long b)` Helper for compareTo implementations.
`static int`	`diff(short a, short b)` Helper for compareTo implementations.
`static boolean`	`equals(Object a, Object b)` A null-safe equality helper.
`static int`	`normalize(int diff)` Helper for compareTo implementations.
`static int`	`normalize(long diff)` Helper for compareTo implementations.

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

Constructor Detail
- CompareUtil
```
protected CompareUtil()
```

Method Detail

equals

public static boolean equals(Object a,
             Object b)

A null-safe equality helper.

 input                   return value
 ------------------------------------
 a == b               => true
 a == null, b != null => false
 a != null, b == null => false
 otherwise            => a.equals(b)

Parameters:: a - -; b - -
Returns:: see above

compare

public static <T> int compare(Comparable<T> a,
              T b)

A null-safe compare helper.

 input                   return value
 ------------------------------------
 a == b                =>  0
 a == null, b != null  => -1
 a != null, b == null  =>  1
 otherwise             =>  a.compareTo(b)

Parameters:: a - -; b - -
Returns:: see above

normalize
```
public static int normalize(int diff)
```
Helper for compareTo implementations. Normalized negative number to -1 and positive non-zero numbers to 1.

Parameters:
diff - the value which shall be normalized

Returns:
see above

normalize
```
public static int normalize(long diff)
```
Helper for compareTo implementations. Normalized negative number to -1 and positive non-zero numbers to 1.

Parameters:
diff - the value which shall be normalized

Returns:
see above

diff

public static int diff(boolean a,
       boolean b)

Helper for compareTo implementations.
Boolean version which considers false < true

 a     b
 -----------------------
 true  true    =>  0
 true  false   =>  1
 false false   =>  0
 false true    => -1

Parameters:: a - -; b - -
Returns:: see above

diff
```
public static int diff(byte a,
       byte b)
```
Helper for compareTo implementations.
Byte version which masks the input values so that an unsigned comparison is performed.
```
 Masks -128 -> 127 => 0 -> 255
 Maps { a<b, a==b, a>b } => { -1, 0, 1 }
 
```
Parameters:
a - -
b - -

Returns:
see above