Class C

java.lang.Object

fc.util.C

public final class C
extends Object

Misc collection related utility methods. Inspired by similar on the web.

Constructor Summary

Constructors

Constructor	Description
C()

Method Summary

Modifier and Type	Method	Description
static fc.util.C.Entry	e(Object key, Object val)	Create a map entry to pass to the map method.
static fc.util.C.Entry	entry(Object key, Object val)	Alias for the e method
static List	list(Object... args)	Create an return a list from the specified args.
static void	main(String[] args)
static Map	map(fc.util.C.Entry... entries)	Create an return a Map from the specified args.
static Map	map(Object... objects)	Create an return a Map from the specified args, which are treated as key, value pairs in sequence.
static boolean	nullOrEmpty(Collection c)	Returns true if the specified collection is null or empty.
static Set	randomNNoDuplicates(List list, int count)	Pick NON-duplicate N random items from a list.
static Set	randomNNoDuplicates(List list, int count, int retries)	Pick NON-duplicate N random items from a list.
static Set	randomNNoDups(List list, int count)	alias for the randomNNoDuplicates(List, int) method
static Set	set(Object... args)	Create an return a Set from the specified args.
static boolean	unbox(Boolean b)	unbox and return false if null
static char	unbox(Character c)	unbox and return '0' if null
static double	unbox(Double d)	unbox and return 0 if null
static int	unbox(Integer i)	unbox and return 0 if null
static long	unbox(Long l)	unbox and return 0 if null
static short	unbox(Short s)	unbox and return 0 if null
static boolean	unboxBool(Object b)	unbox and return false if null
static boolean	unboxBoolean(Object b)	unbox and return false if null
static char	unboxChar(Object c)	unbox and return '0' if null
static double	unboxDouble(Object d)	unbox and return 0 if null
static int	unboxInt(Object i)	unbox and return 0 if null
static long	unboxLong(Object i)	unbox and return 0 if null
static short	unboxShort(Object s)	unbox and return 0 if null

Methods inherited from class Object

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

Constructor Details

C

public C()

Method Details

list

public static List list(Object... args)

Create an return a list from the specified args.

set

public static Set set(Object... args)

Create an return a Set from the specified args.

map

public static Map map(Object... objects)

Create an return a Map from the specified args, which are treated as key, value pairs in sequence. Example: Map map = map("a", "hello", "b", 123, "c", new int[] {4,5,6});

map

public static Map map(fc.util.C.Entry... entries)

Create an return a Map from the specified args. Example: Map map = map(e("a", "hello"), e("b", 123));

entry

public static fc.util.C.Entry entry(Object key,
 Object val)

Alias for the e method

e

public static fc.util.C.Entry e(Object key,
 Object val)

Create a map entry to pass to the map method. values can be null. The key, value pairs are accessed directly after they are put in the map.

randomNNoDuplicates

public static Set randomNNoDuplicates(List list,
 int count)
                               throws IllegalArgumentException

Pick NON-duplicate N random items from a list. If N invalid input: '<' number of unique items in the list, throws a IllegalArgumentException. Also throws a IllegalArgumentException if not able to get unique items after 16 tries (per item). To specify a different retry count (per item), use the variant of this method that takes the retry parameter.

Parameters:

count - number (N) items to choose.

Throws:

IllegalArgumentException

randomNNoDups

public static Set randomNNoDups(List list,
 int count)
                         throws IllegalArgumentException

alias for the randomNNoDuplicates(List, int) method

Throws:

IllegalArgumentException

randomNNoDuplicates

public static Set randomNNoDuplicates(List list,
 int count,
 int retries)
                               throws IllegalArgumentException

Pick NON-duplicate N random items from a list. If N invalid input: '<' number of unique items in the list, throws a IllegalArgumentException. Also throws a IllegalArgumentException if not able to get unique items after the specified (per item).

Parameters:

count - number (N) items to choose.

retries - number of retries to get a unique random item before bailing/throwing an Exception

Throws:

IllegalArgumentException

unbox

public static short unbox(Short s)

unbox and return 0 if null

unboxShort

public static short unboxShort(Object s)

unbox and return 0 if null

unbox

public static int unbox(Integer i)

unbox and return 0 if null

unboxInt

public static int unboxInt(Object i)

unbox and return 0 if null

unbox

public static long unbox(Long l)

unbox and return 0 if null

unboxLong

public static long unboxLong(Object i)

unbox and return 0 if null

unbox

public static double unbox(Double d)

unbox and return 0 if null

unboxDouble

public static double unboxDouble(Object d)

unbox and return 0 if null

unbox

public static char unbox(Character c)

unbox and return '0' if null

unboxChar

public static char unboxChar(Object c)

unbox and return '0' if null

unbox

public static boolean unbox(Boolean b)

unbox and return false if null

unboxBool

public static boolean unboxBool(Object b)

unbox and return false if null

unboxBoolean

public static boolean unboxBoolean(Object b)

unbox and return false if null

nullOrEmpty

public static boolean nullOrEmpty(Collection c)

Returns true if the specified collection is null or empty.

main

public static void main(String[] args)