Osp::Base::Collection

Transcription

1 Osp::Base::Collection

2 Contents Collections Interfaces and Enumerators Helpers Lists Maps and MultiMaps Stack and Queue 2

3 Introduction A collection means an aggregation of similar objects. The collection refers to the container rather than its contents. This namespace provides template-based and non-template based classes common data structures and their Enumerators. 3

4 1 Collections

5 Collections Collection A group/aggregation of multiple homogeneous items Provide generic APIs for common operations like access, add, delete, modify etc. Are efficient, reusable, and extensible Collections classes can be categorized into Lists: ArrayList, ArrayListT, LinkedList, LinkedListT Maps: HashMap, HashMapT Multi Maps: MultiHashMap, MultiHashMapT Stacks: Stack, StackT Queues: Queue, QueueT 5

6 2 Interfaces and Enumerators

7 Interfaces and Enumerators Interfaces Virtual classes Facilitates basic functionalities Provide reusability and extensibility Enumerators A special kind of interface supports a simple iteration over a collection Can t modify the member object of a collection Remains valid as long as the collection remains unchanged Generic APIs GetCurrent() MoveNext() Reset() 7

8 ICollection & IEnumerator ICollection Base interface of collection classes APIs GetCount() GetEnumeratorN() IEnumerator Base interface of all enumerator All concrete collection classes must be derived from this to allow iteration over its objects APIs GetCurrent() MoveNext() (returns E_OUT_OF_RANGE at its end) Reset() 8

9 IList Base interface of all concrete list classes Items are accessible by index and provides functionalities for Adding items Add(), AddItems(), InsertAt(), InsertItemsFrom() Removing items Remove() (by object), RemoveAt() (by index), RemoveAll(), RemoveItems() (by range), RemoveItems() (by another collection) Random access GetAt(), SetAt(), GetItemsN() Search IndexOf(), LastIndexOf(), Contains(), ContainsAll(), Sort (by IComparer) 9

10 IMap Key-Value pairs Adding & removing Add(), Remove() (by a key), RemoveAll() Searching ContainsKey(), ContainsValue(), GetValue() (by a key) Getting & setting GetKeysN(), GetValuesN(), GetMapEnumeratorN() SetValue() (by a key with a new value) 10

11 IMultiMap Multiple values for a key Specific functions Contains() (by a key and value pair) GetCount() (by a key), GetCount (all), GetValuesN (by a key) Remove() (by a value and key pair) SetValue() (by a value and key pair with a new value) 11

12 More Enumerators Osp::Base::Collection::IMapEnumerator GetKey() GetValue() GetCurrent() (returns MapEntry) MapEntry: a small class supports GetKey(), GetValue() & Equals() Osp::Base::Collection::IBidirectionalEnumerator MovePrevious() ResetLast() 12

13 4 Helpers

14 IHashCodeProvider Interface which implements the hash code mechanism All classes which need hash calculation should implement this interface s GetHashCode() method. 14

15 IComparer Allows a derived class to compare two objects of the same type Implements the comparison functionality of two objects Implementations are DoubleComparer FloatComparer Int8Comparer... StringComparer 15

16 5 List

17 ArrayList & LinkedList Collection of objects that can be individually accessed by an index A real class supporting IList Implemented based on array Initial capacity is 10 if not specified ArrayList specific functions SetCapacity() Do not add a stack objects into a collection Wrong: String str(l One ); list.add(str); Instead add heap based objects, String* str = new String(L One ); list.add(*str); 17

18 Example: ArrayList Operations ArrayList list; // Create the ArrayList instance list.construct(); // Construct the ArrayList with default capacity // Adding values list.add(*(new Integer(1))); // 1 list.add(*(new Integer(2))); // 1 2 // Retrieve and insert new value at index 1 Integer* i = static_cast<integer*>(list.getat(1)); list.insertat(*(new Integer(4)),1); // // Removing with value Integer* val = new Integer(1); list.remove(*val,true); // 4 2 delete val; // Removing at Index list.removeat(1,true); // 4 // Adding more values list.add(*(new Integer(1))); // 4 1 list.add(*(new Integer(3))); //

19 Example: Sorting & Enumerating // Sorting list IntegerComparer* com = new IntegerComparer(); list.sort(*com); // [1 3 4] delete com; // Enumerator example IEnumerator* enumn = list.getenumeratorn(); while( enumn->movenext() == E_SUCCESS ) { Integer* obj = (Integer*)(enumN->GetCurrent()); AppLog( "[%d]", obj->toint() ); } delete enumn; // which is the same to for( int i=0; i<list.getcount(); i++ ) { Integer* obj = (Integer*)(list.GetAt(i)); AppLog( "[%d]", obj->toint() ); } 19

20 8 Maps and MultiMaps

21 HashMap & MultiHashMap Implementation of IMap & IMultiMap Organized based on the hash code of the keys Default capacity is 16 HashMap contains unique keys and each key maps to one single value. MultiHashMap has no limit on the number of elements with the same key, but duplicated elements with the same key are not allowed. 21

22 Example: HashMap Operations HashMap map; map.construct(); // Key strings String* keyname = new String(L"Name"); String* keyage = new String(L"Age"); String* keyphone = new String(L"Phone"); // Adding Key-value pairs map.add(*keyname, *(new String("John"))); map.add(*keyage, *(new Integer(15))); map.add(*keyphone, *(new String(" "))); // Getting the value for a key Integer* age=static_cast<integer*>(map.getvalue(*keyage)); // 15 // Deleting a pair map.remove(*keyage, true); 22

23 Example: Enumeration // Enumerating IMapEnumerator* mapenum = map.getmapenumeratorn(); while (mapenum->movenext() == E_SUCCESS) { String* k =static_cast<string*> (mapenum->getkey()); String* v =static_cast<string*> (mapenum->getvalue()); AppLog( [%S]->[%S], k->getpointer(),v->getpointer()); } delete mapenum; // Deallocate all objects map.removeall(true); 23

24 9 Stack and Queue

25 Stack & Queue Conventional stacks and queues Implements ICollection Stack specific functions Push(), Pop(), Peek() (object at the top without removing) Queue specific functions Enqueue(), Dequeue(), Peek() (at the front) Note: both also supports enumerator by GetEnumerator() GetCount(), Contains(), ContainsAll(), Equals(), RemoveAll() 25

26 Summary ArrayList and LinkedList are real implementations of the IList class. Support sorting using IComparer Enumerators can be used to enumerate collection objects. HashMap is a collection type class which stores key-value pairs. Inbuilt data structures are provided for stack and queue related operations. 26

27 Practice Example Write a image slideshow application using ArrayList and Timer class. 27