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THÔNG TIN TÀI LIỆU
Cấu trúc
Slide 1
Introduction to Collections
What is a Collections Framework
Collections Interface
Collections Implementations
Collections Implementations
Collection Implementations
Concrete Classes: Collection
Concrete Class: MAP
Collections Comparision
1) Collection Interface:Traversing Collections
2) Collection Interface: Bulk Operations
3) Collection Interface: Array Operations
Set Interface
1) Set Interface: Basic Operations
2) Set Interface: Bulk Operations
HỎI ĐÁP
List Interface
List Interface
List Interface: Interators
Queue Interface
Map Interface
Nội dung
GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU COLLECTIONs FRAMEWORK /XX 12/3/15 CẤU TRÚC DỮ LIỆU DATA STRUCTURES [214441] Nguyễn Xuân Vinh nguyenxuanvinh@hcmuaf.edu.vn GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX Introduction to Collections 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 Represent data items that form a natural group, such as: A poker hand (a collection of cards) A mail folder (a collection of letters) A telephone directory (a mapping of names to phone numbers) GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX What is a Collections Framework A collections framework is a unified architecture for representing and manipulating collections All collections frameworks contain the following: Interfaces: These are abstract data types that represent collections Implementations: These are the concrete implementations of the collection interfaces Algorithms: These are the methods that perform useful computations, such as searching and sorting /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collections Interface /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collections Implementations /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collections Implementations /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collection Implementations /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Concrete Classes: Collection /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Concrete Class: MAP 10 /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collections Comparision GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 11 1) Collection Interface:Traversing Collections There are two ways to traverse collections: (1) with the for-each construct for (Object o : collection) System.out.println(o); (2) by using Iterators Iterator iterator = collection.iterator(); while(iterator.hasNext()) { System.out.println(iterator.next()); } GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 12 2) Collection Interface: Bulk Operations containsAll — returns true if the target Collection contains all of the elements in the specified Collection addAll — adds all of the elements in the specified Collection to the target Collection removeAll — removes from the target Collection all of its elements that are also contained in the specified Collection retainAll — removes from the target Collection all its elements that are not also contained in the specified Collection. That is, it retains only those elements in the target Collection that are also contained in the specified Collection clear — removes all elements from the Collection GV: NGUYỄN XUÂN VINH 3) Collection Interface: Array Operations The toArray methods are provided as a bridge between collections and older APIs that expect arrays on input For example, suppose that c is a Collection: 13 /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU Object[] a = c.toArray(); String[] a = c.toArray(new String[0]); GV: NGUYỄN XUÂN VINH public interface Set extends Collection { // Basic operations int size(); boolean isEmpty(); boolean contains(Object element); // optional boolean add(E element); // optional boolean remove(Object element); Iterator iterator(); // Bulk operations boolean containsAll(Collection c); // optional boolean addAll(Collection c); // optional boolean retainAll(Collection c); // optional void clear(); 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU Set Interface 14 /XX // Array Operations Object[] toArray(); T[] toArray(T[] a); } GV: NGUYỄN XUÂN VINH public class FindDups { public static void main(String[] args) { Set s = new HashSet(); for (String a : args) if (!s.add(a)) System.out.println("Duplicate detected: " + a); System.out.println(s.size() + " distinct words: " + s); } } Duplicate detected: i distinct words: [i, left, saw, came] 15 12/3/15 Run: java FindDups i came i saw i left Output produced: Duplicate detected: i /XX MÔN: CẤU TRÚC DỮ LIỆU 1) Set Interface: Basic Operations GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 16 2) Set Interface: Bulk Operations s1.containsAll(s2) — returns true if s2 is a subset of s1. (s2 is a subset of s1 if set s1 contains all of the elements in s2.) s1.addAll(s2) — transforms s1 into the union of s1 and s2. (The union of two sets is the set containing all of the elements contained in either set.) s1.retainAll(s2) — transforms s1 into the intersection of s1 and s2. (The intersection of two sets is the set containing only the elements common to both sets.) s1.removeAll(s2) — transforms s1 into the (asymmetric) set difference of s1 and s2. (For example, the set difference of s1 minus s2 is the set containing all of the elements found in s1 but not in s2.) 17 /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH HỎI ĐÁP GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 18 List Interface A List is an ordered Collection (sometimes called a sequence). Lists may contain duplicate elements. In addition to the operations inherited from Collection, the List interface includes operations for the following: Positional access — manipulates elements based on their numerical position in the list Search — searches for a specified object in the list and returns its numerical position Iteration — extends Iterator semantics to take advantage of the list's sequential nature Range-view — performs arbitrary range operations on the list GV: NGUYỄN XUÂN VINH public interface List extends Collection { // Positional access E get(int index); // optional E set(int index, E element); // optional boolean add(E element); // optional void add(int index, E element); // optional E remove(int index); // optional boolean addAll(int index, Collection[...]... difference of s1 and s2. (For example, the set difference of s1 minus s2 is the set containing all of the elements found in s1 but not in s2.) 17 /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH HỎI ĐÁP GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 18 List Interface A List is an ordered Collection (sometimes called a sequence). Lists may contain duplicate elements. In addition to the operations ... Duplicate detected: i 4 distinct words: [i, left, saw, came] 15 12/3/15 Run: java FindDups i came i saw i left Output produced: Duplicate detected: i /XX MÔN: CẤU TRÚC DỮ LIỆU 1) Set Interface: Basic Operations GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 16 2) Set Interface: Bulk Operations s1.containsAll(s2) — returns true if s2 is a subset of s1. (s2 is a subset of s1 if set s1 contains all of the elements in s2.)...GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 11 1) Collection Interface:Traversing Collections There are two ways to traverse collections: (1) with the for-each construct for (Object o : collection) System.out.println(o); (2) by using Iterators Iterator iterator = collection.iterator(); while(iterator.hasNext()) { System.out.println(iterator.next()); } GV: NGUYỄN XUÂN VINH MÔN: CẤU... indexOf(Object o); int lastIndexOf(Object o); // Iteration ListIterator listIterator(); ListIterator listIterator(int index); 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU List Interface 19 /XX // Range-view List subList(int from, int to); } GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 20 List Interface: Interators public interface ListIterator extends Iterator { boolean hasNext(); E next(); boolean... clear — removes all elements from the Collection GV: NGUYỄN XUÂN VINH 3) Collection Interface: Array Operations The toArray methods are provided as a bridge between collections and older APIs that expect arrays on input For example, suppose that c is a Collection: 13 /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU Object[] a = c.toArray(); String[] a = c.toArray(new String[0]); GV: NGUYỄN XUÂN VINH public interface Set extends... E> c); // optional boolean removeAll(Collection c); // optional boolean retainAll(Collection c); // optional void clear(); 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU Set Interface 14 /XX // Array Operations Object[] toArray(); T[] toArray(T[] a); } GV: NGUYỄN XUÂN VINH public class FindDups { public static void main(String[] args) { Set s = new HashSet(); for (String a : args) if (!s.add(a))... boolean hasNext(); E next(); boolean hasPrevious(); E previous(); int nextIndex(); int previousIndex(); void remove(); //optional void set(E e); //optional void add(E e); //optional } GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15 /XX 21 Queue Interface public interface Queue extends Collection { E element(); boolean offer(E e); E peek(); E poll(); E remove(); } public interface Map { //... Basic operations V put(K key, V value); V get(Object key); V remove(Object key); boolean containsKey(Object key); boolean containsValue(Object value); int size(); boolean isEmpty(); MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Map Interface // Bulk operations void putAll(Map ... 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Concrete Class: MAP 10 /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collections Comparision GV: NGUYỄN XUÂN VINH MÔN: CẤU TRÚC DỮ LIỆU 12/3/15... MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collections Interface /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collections Implementations /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN... GV: NGUYỄN XUÂN VINH Collections Implementations /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Collection Implementations /XX 12/3/15 MÔN: CẤU TRÚC DỮ LIỆU GV: NGUYỄN XUÂN VINH Concrete