Module de.cuioss.java.tools
Package de.cuioss.tools.collect

Class MoreCollections

java.lang.Object
de.cuioss.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

  • Constructor Summary

    Constructors
    Constructor
    Description
    MoreCollections()
     

  • 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

  • Constructor Details

  • Method Details

    • 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