Package io.cui.tools.collect

Class MoreCollections

java.lang.Object

io.cui.tools.collect.MoreCollections

public final class MoreCollections
extends Object

Overview

Utility Methods for Collections and some types to be used in the context of Collections.

isEmpty()

The overloaded method isEmpty(Collection) checks all kinds of Collections / varargs parameter for not being null and emptiness. In case of Streams it solely checks for being not null in order not to consume it.

requireNotEmpty()

The overloaded method requireNotEmpty(Collection) checks all kinds of Collections / varargs parameter for not being null nor empty. In case of being null / empty they will throw an IllegalArgumentException

Map Difference

The method difference(Map, Map) creates an MapDifference view on the two given maps in order to check, well whether they are equal or not and if not which elements are differing.

Map contains key

Check whether the given Map contains at least one of the given keys (varags)

Author:

Oliver Wolff

Method Summary

Modifier and Type	Method	Description
static boolean	containsKey(Map<?,?> map, Object... keys)	Checks whether the given map contains at least one of the given keys to be checked.
static <K,V> MapDifference<K,V>	difference(Map<? extends K,? extends V> left, Map<? extends K,? extends V> right)	Computes the difference between two maps.
static boolean	isEmpty(Iterable<?> elements)	Simple check method for a null safe check of the emptiness of the given parameter.
static boolean	isEmpty(Object... elements)	Simple check method for a null safe check of the emptiness of the given varags-parameter.
static boolean	isEmpty(Collection<?> elements)	Simple check method for a null safe check of the emptiness of the given parameter.
static boolean	isEmpty(Iterator<?> elements)	Simple check method for a null safe check of the emptiness of the given parameter.
static boolean	isEmpty(Map<?,?> map)	Simple check method for a null safe check of the emptiness of the given parameter.
static boolean	isEmpty(Stream<?> elements)	Simple check method for a null safe check of the emptiness of the given parameter.
static <T> Iterable<T>	requireNotEmpty(Iterable<T> elements)	Shorthand for checking whether the given elements are empty or not.
static <T> Iterable<T>	requireNotEmpty(Iterable<T> elements, String message)	Shorthand for checking whether the given elements are empty or not.
static <T> Collection<T>	requireNotEmpty(Collection<T> elements)	Shorthand for checking whether the given elements are empty or not.
static <T> Collection<T>	requireNotEmpty(Collection<T> elements, String message)	Shorthand for checking whether the given elements are empty or not.
static <T> Iterator<T>	requireNotEmpty(Iterator<T> elements)	Shorthand for checking whether the given elements are empty or not.
static <T> Iterator<T>	requireNotEmpty(Iterator<T> elements, String message)	Shorthand for checking whether the given elements are empty or not.
static <K,V> Map<K,V>	requireNotEmpty(Map<K,V> elements)	Shorthand for checking whether the given elements are empty or not.
static <K,V> Map<K,V>	requireNotEmpty(Map<K,V> elements, String message)	Shorthand for checking whether the given elements are empty or not.
static <T> Stream<T>	requireNotEmpty(Stream<T> elements)	Shorthand for checking whether the given elements are empty or not.
static <T> Stream<T>	requireNotEmpty(Stream<T> elements, String message)	Shorthand for checking whether the given elements are empty or not.
static <T> T[]	requireNotEmpty(T... elements)	Shorthand for checking whether the given elements are empty or not.

Methods inherited from class java.lang.Object

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

Method Detail

isEmpty

public static boolean isEmpty(Object... elements)

Simple check method for a null safe check of the emptiness of the given varags-parameter.

Parameters:

elements - to be checked, may be null

Returns:

true is the given elements are null or empty

isEmpty

public static boolean isEmpty(Iterable<?> elements)

Simple check method for a null safe check of the emptiness of the given parameter.

Parameters:

elements - to be checked, may be null

Returns:

true is the given elements are null or empty

isEmpty

public static boolean isEmpty(Collection<?> elements)

Simple check method for a null safe check of the emptiness of the given parameter.

Parameters:

elements - to be checked, may be null

Returns:

true is the given elements are null or empty

isEmpty

public static boolean isEmpty(Map<?,?> map)

Simple check method for a null safe check of the emptiness of the given parameter.

Parameters:

map - to be checked, may be null

Returns:

true is the given elements are null or empty

isEmpty

public static boolean isEmpty(Iterator<?> elements)

Simple check method for a null safe check of the emptiness of the given parameter.

Parameters:

elements - to be checked, may be null

Returns:

true is the given elements are null or empty

requireNotEmpty

@SafeVarargs
public static <T> T[] requireNotEmpty(T... elements)

Shorthand for checking whether the given elements are empty or not.

Type Parameters:

T - identifying the type to be checked

Parameters:

elements - to be checked

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <T> Collection<T> requireNotEmpty(Collection<T> elements)

Shorthand for checking whether the given elements are empty or not.

Type Parameters:

T - identifying the type to be checked

Parameters:

elements - to be checked

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <T> Collection<T> requireNotEmpty(Collection<T> elements,
                                                String message)

Shorthand for checking whether the given elements are empty or not.

Type Parameters:

T - identifying the type to be checked

Parameters:

elements - to be checked

message - to be set in error-case

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <K,V> Map<K,V> requireNotEmpty(Map<K,V> elements)

Shorthand for checking whether the given elements are empty or not.

Type Parameters:

K - the type for the key

V - the type for the value

Parameters:

elements - to be checked

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <K,V> Map<K,V> requireNotEmpty(Map<K,V> elements,
                                                         String message)

Shorthand for checking whether the given elements are empty or not.

Type Parameters:

K - the type for the key

V - the type for the value

Parameters:

elements - to be checked

message - to be set in error-case

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <T> Iterable<T> requireNotEmpty(Iterable<T> elements)

Shorthand for checking whether the given elements are empty or not.

Type Parameters:

T - identifying the type to be checked

Parameters:

elements - to be checked

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <T> Iterable<T> requireNotEmpty(Iterable<T> elements,
                                              String message)

Shorthand for checking whether the given elements are empty or not.

Type Parameters:

T - identifying the type to be checked

Parameters:

elements - to be checked

message - to be set in error-case

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <T> Iterator<T> requireNotEmpty(Iterator<T> elements)

Shorthand for checking whether the given elements are empty or not.

Parameters:

elements - to be checked

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <T> Iterator<T> requireNotEmpty(Iterator<T> elements,
                                              String message)

Shorthand for checking whether the given elements are empty or not.

Type Parameters:

T - identifying the type to be checked

Parameters:

elements - to be checked

message - to be set in error-case

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null or empty

requireNotEmpty

public static <T> Stream<T> requireNotEmpty(Stream<T> elements)

Shorthand for checking whether the given elements are empty or not. Caution: In order not to consume the stream only a null check will be performed.

Type Parameters:

T - identifying the type to be checked

Parameters:

elements - to be checked

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null

requireNotEmpty

public static <T> Stream<T> requireNotEmpty(Stream<T> elements,
                                            String message)

Shorthand for checking whether the given elements are empty or not. Caution: In order not to consume the stream only a null check will be performed.

Type Parameters:

T - identifying the type to be checked

Parameters:

elements - to be checked

message - to be set in error-case

Returns:

the given parameter

Throws:

IllegalArgumentException - in case the given elements are null

isEmpty

public static boolean isEmpty(Stream<?> elements)

Simple check method for a null safe check of the emptiness of the given parameter. Caution: In order not to consume the stream only a null check will be performed.

Parameters:

elements - to be checked, may be null

Returns:

true is the given elements are null. The Stream content will be untouched

Throws:

IllegalArgumentException - in case the given elements are null

containsKey

public static boolean containsKey(Map<?,?> map,
                                  Object... keys)

Checks whether the given map contains at least one of the given keys to be checked.

Parameters:

map - to be checked. If it is null or empty the method will always return false

keys - to be checked. If it is null or empty the method will always return false

Returns:

true if the map contains at lest one of the given keys, false otherwise

difference

public static <K,V> MapDifference<K,V> difference(Map<? extends K,? extends V> left,
                                                              Map<? extends K,? extends V> right)

Computes the difference between two maps. This difference is an immutable snapshot of the state of the maps at the time this method is called. It will never change, even if the maps change at a later time.

Since this method uses HashMap instances internally, the keys of the supplied maps must be well-behaved with respect to Object.equals(java.lang.Object) and Object.hashCode().

Note:If you only need to know whether two maps have the same mappings, call left.equals(right) instead of this method.

Type Parameters:

K - the type for the key

V - the type for the value

Parameters:

left - the map to treat as the "left" map for purposes of comparison, must not be null

right - the map to treat as the "right" map for purposes of comparison , must not be null

Returns:

the difference between the two maps