The Collections Framework

• A collection — sometimes called a container — is simply an object that groups multiple elements into a single unit. Collections are used to store, retrieve, manipulate, and communicate aggregate data.
• a unified architecture for representing and manipulating collections, enabling them to be manipulated independently of the details of their representation
• Content
  • Interfaces

    These are abstract data types that represent collections. Interfaces allow collections to be manipulated independently of the details of their representation. In object-oriented languages, interfaces generally form a hierarchy.

  • Implementations

    These are the concrete implementations of the collection interfaces. In essence, they are reusable data structures.

  • Algorithms

    These are the methods that perform useful computations, such as searching and sorting, on objects that implement collection interfaces

• Interface Hierachy

  

• Full Hierachy

  

• Implementation

  

• Algorithms
  • sorting

    Collections.sort(list); or Collections.sort(list, Comparator);

  • shuffling

      public static void shuffle(List<?> list, Random rnd) {
          for (int i = list.size(); i > 1; i--) {
              swap(list, i - 1, rnd.nextInt(i));
          }
      }
    

    Collections.shuffle(list); or Collections.shuffle(list, new Random());

  • Routine Data Manipulation
    • reverse

      reverses the order of the elements in a List.

    • fill

      overwrites every element in a List with the specified value. This operation is useful for reinitializing a List.

    • copy

      takes two arguments, a destination List and a source List, and copies the elements of the source into the destination, overwriting its contents. The destination List must be at least as long as the source. If it is longer, the remaining elements in the destination List are unaffected.

    • swap

      swaps the elements at the specified positions in a List.

    • addAll

      adds all the specified elements to a Collection. The elements to be added may be specified individually or as an array.

  • Searching

    Collections.binarySearch(list, key);

    If the List contains the search key, its index is returned. If not, the return value is (-(insertion point) - 1)