CollectionHelper (Java Common Helper 0.0.11-SNAPSHOT API)

java.lang.Object
- com.blibli.oss.common.helper.CollectionHelper

public class CollectionHelper
extends Object

Author:: william.s.setiadi on 2/19/2018.

Constructor Summary

Constructors
Constructor and Description

CollectionHelper()

Constructors
Constructor and Description
`CollectionHelper()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static <T,V extends T> List<T>`	`addToList(List<T> list, V... elems)` Denullifies the given `list` and adds `elems` to it.
`static <T> T`	`findInCollection(Collection<T> coll, java.util.function.Predicate<T> func)` Finds the first element in the collection that satisfies the predicate `func`.
`static <T> void`	`forEach(Iterable<T> coll, java.util.function.Consumer<T> func)` Executes function `func` on the given collection `coll`.
`static boolean`	`isEmpty(Collection<?> coll)` Checks if `coll` is either null or empty.
`static boolean`	`isEmpty(Map<?,?> map)` Checks if `map` is either null or empty.
`static <T> boolean`	`isInCollection(T ele, Collection<T> coll)` Checks whether `ele` is in the given `coll`.
`static <E extends Enum<E>> boolean`	`isInEnumSet(E e, E... enums)` Checks if the enum `e` is in the given array of `enums`.
`static boolean`	`isNotEmpty(Collection<?> coll)` Negation of `isEmpty(Collection)`.
`static boolean`	`isNotEmpty(Map<?,?> map)` Negation of `isEmpty(Map)`.
`static void`	`sanitize(Collection<?> coll)` Removes null elements from the collection.
`static void`	`sanitize(Map<?,?> map)` Removes elements with either null key or null value from the map.
`static int`	`sizeOf(Collection<?> coll)` Returns the size of the given collection.
`static <T> List<T>`	`toList(T... elems)` Converts the given array of elements of type T to a new instance of `ArrayList` of the same type.
`static <T> Set<T>`	`toSet(T... elems)` Converts the given array of elements of type T to a new instance of `HashSet` of the same type.

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

- Constructor Detail
  - CollectionHelper
```
public CollectionHelper()
```
- Method Detail
  - addToList
```
public static <T,V extends T> List<T> addToList(List<T> list,
                                                V... elems)
```
    Denullifies the given list and adds elems to it.
    Will not add null elements into the list.
    
    Type Parameters:
    
    T - type of the list
    
    V - type of the elements. Must be a subclass of <T>
    
    Parameters:
    
    list - to add elements to
    
    elems - elements to be added to the list. Null elements will not be added into the list
    
    Returns:
    
    list appended with the specified non-null elements
    
    See Also:
    
    CommonHelper.denullify(List)
  - findInCollection
```
public static <T> T findInCollection(Collection<T> coll,
                                     java.util.function.Predicate<T> func)
```
    Finds the first element in the collection that satisfies the predicate func.
    
    Type Parameters:
    
    T - type of collection's content
    
    Parameters:
    
    coll - collection to be iterated
    
    func - a boolean function to evaluate the elements in coll
    
    Returns:
    
    the first matching element. Returns null if coll is empty or no matching element is found
  - forEach
```
public static <T> void forEach(Iterable<T> coll,
                               java.util.function.Consumer<T> func)
```
    Executes function func on the given collection coll.
    Performs null check on both the function and the collection.
    
    Type Parameters:
    
    T - both the collection and function must be of the same type
    
    Parameters:
    
    coll - subclass of Iterable on which the function func will be performed
    
    func - function to be performed on each element of the collection coll
  - isEmpty
```
public static boolean isEmpty(Collection<?> coll)
```
    Checks if coll is either null or empty.
    
    Parameters:
    
    coll - collection to be checked, may be any subclass or implementation of Collection
    
    Returns:
    
    true if coll is empty or null, false otherwise
  - isEmpty
```
public static boolean isEmpty(Map<?,?> map)
```
    Checks if map is either null or empty.
    
    Parameters:
    
    map - map to be checked, may be any subclass or implementation of Map
    
    Returns:
    
    true if map is empty or null, false otherwise
  - isInCollection
```
public static <T> boolean isInCollection(T ele,
                                         Collection<T> coll)
```
    Checks whether ele is in the given coll. Comparison is done by invoking Collection.contains(Object).
    Be careful of incorrect equals() implementation (e.g. not calling super.equals()) as this may lead to incorrect result.
    Type Parameters:
    
    T - type of element
    
    Parameters:
    
    ele - to be evaluated against
    
    coll - to be iterated over
    
    Returns:
    true if element is found in the collection.
    false if one of the following is true:
    
    element is null
    
    collection is empty or null
    
    element is not found in the collection
  - isInEnumSet
```
public static <E extends Enum<E>> boolean isInEnumSet(E e,
                                                      E... enums)
```
    Checks if the enum e is in the given array of enums. Comparison is done by invoking e.equals().
    Type Parameters:
    
    E - type of enum
    
    Parameters:
    
    e - to be checked
    
    enums - to be iterated over
    
    Returns:
    true if e is found in enums.
    false if one of the following is true:
    
    e is null
    
    enums is null
    
    e is not found in enums
  - isNotEmpty
```
public static boolean isNotEmpty(Collection<?> coll)
```
    Negation of isEmpty(Collection).
    
    Parameters:
    
    coll - to be checked
    
    Returns:
    
    true if coll is neither null nor empty, false otherwise
  - isNotEmpty
```
public static boolean isNotEmpty(Map<?,?> map)
```
    Negation of isEmpty(Map).
    
    Parameters:
    
    map - to be checked
    
    Returns:
    
    true if map is neither null nor empty, false otherwise
  - sanitize
```
public static void sanitize(Collection<?> coll)
```
    Removes null elements from the collection.
    
    Parameters:
    
    coll - to be sanitized
    
    Throws:
    
    UnsupportedOperationException - if the collection is immutable or fixed-size
    
    See Also:
    
    Collection.removeIf(java.util.function.Predicate)
  - sanitize
```
public static void sanitize(Map<?,?> map)
```
    Removes elements with either null key or null value from the map.
    
    Parameters:
    
    map - to be sanitized
    
    Throws:
    
    UnsupportedOperationException - if the map is immutable or fixed-size
    
    See Also:
    
    Collection.removeIf(java.util.function.Predicate)
  - sizeOf
```
public static int sizeOf(Collection<?> coll)
```
    Returns the size of the given collection.
    
    Parameters:
    
    coll - any subclass or implementation of Collection
    
    Returns:
    
    0 if the collection is empty, otherwise returns the collection's size
    
    See Also:
    
    isEmpty(Collection)
  - toSet
```
public static <T> Set<T> toSet(T... elems)
```
    Converts the given array of elements of type T to a new instance of HashSet of the same type. Only adds non-null elements into the set.
    
    Type Parameters:
    
    T - type of elements which will be converted to HashSet
    
    Parameters:
    
    elems - to be converted into a HashSet
    
    Returns:
    
    new HashSet of type T. Set will be populated by non-null members of elems. Never returns null.
  - toList
```
public static <T> List<T> toList(T... elems)
```
    Converts the given array of elements of type T to a new instance of ArrayList of the same type. Only adds non-null elements into the list.
    
    Type Parameters:
    
    T - type of elements which will be converted to List
    
    Parameters:
    
    elems - to be converted into a List
    
    Returns:
    
    new ArrayList of type T. List will be populated by non-null members of elems. Never returns null.
    
    See Also:
    
    Collectors.toList()

Class CollectionHelper

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

CollectionHelper

Method Detail

addToList

findInCollection

forEach

isEmpty

isEmpty

isInCollection

isInEnumSet

isNotEmpty

isNotEmpty

sanitize

sanitize

sizeOf

toSet

toList