[a, b, X, c, d, e, f, a, g]
[a, b, X, c, d, e, f, W, g]
[b, X, c, d, e, f, W, g] a
LinkedList<E> . , , , .
LinkedList<E> void addFirst(E ob), void addLast(E ob), E getFirst(),
E getLast(), E removeFirst(), E removeLast() , , .
LinkedList<E> Queue<E>, , . Queue<E> E element(), boolean offer(E o), E peek(), E poll() , E remove() , LinkedList<E>.
Queue<E>: E element() , ; boolean offer(E o) , ; E peek() , , null , ; E poll() , null , ; E remove() .element() remove() peek() poll() , , .
/* # 5: : DemoLinkedList.java */
package chapt10;
import java.util.*;
public class DemoLinkedList {
public static void main(String[] args){
LinkedList<Number> a = new LinkedList<Number>();
for (int i = 10; i <= 15; i++)
a.add(i);
for (int i = 16; i <= 20; i++)
a.add(new Float(i));
ListIterator<Number> list = a.listIterator(10);
System. out. println("\n"+ list.nextIndex()
+ "- ");
list.next(); // !
System. out. println(list.nextIndex()
+ "- ");
list.remove(); //
while (list.hasPrevious())
System. out. print(list.previous()+" "); /*
*/
//
a.removeFirst();
a.offer(71); //
a.poll(); //
a.remove(); //
a.remove(1); //
System. out. println("\n" + a);
Queue<Number> q = a; //
for (Number i: q) //
System. out. print(i + " ");
System. out. println(":size= " + q.size());
//
for (int i = 0; i < 5; i++) {
Number res = q.poll();
}
System. out. print("size= " + q.size());
}
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|
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}
:
19.0 18.0 17.0 16.0 15 14 13 12 11 10
[13, 15, 16.0, 17.0, 18.0, 19.0, 71]
13 15 16.0 17.0 18.0 19.0 71:size= 7
size= 2
Comparator<T> , . int compare(T ob1,
T ob2), , . public static <T> void sort(List<T> list, Comparator<? super T> c) Collections, , -comparator, .
/* # 6: : UniqSortMark.java */
package chapt10;
import java.util.Comparator;
public class Student implements Comparator<Student> {
private int idStudent;
private float meanMark;
public Student(float m, int id) {
meanMark = m;
idStudent = id;
}
public Student() {
}
public float getMark() {
return meanMark;
}
public int getIdStudent() {
return idStudent;
}
//
public int compare(Student one, Student two) {
Return
(int)(Math.ceil(two.getMark() - one.getMark()));
}
}
package chapt10;
import java.util.*;
public class UniqSortMark {
public static void main(String[] args) {
ArrayList<Student> p = new ArrayList<Student>();
p.add(new Student(3.9f, 52201));
p.add(new Student(3.65f, 52214));
p.add(new Student(3.71f, 52251));
p.add(new Student(3.02f, 52277));
p.add(new Student(3.81f, 52292));
p.add(new Student(9.55f, 52271));
//
try {
Collections.sort(p, Student. class. newInstance ());
} catch (InstantiationException e1) {
//
e1.printStackTrace();
} catch (IllegalAccessException e2) {
e2.printStackTrace();
}
for (Student ob: p)
System.out.printf("%.2f ", ob.getMark());
}
}
:
9,55 3,90 3,81 3,71 3,65 3,02
boolean equals(Object obj) Comparator<T>, , true compare() 0.
id Student , Comparator .
/* # 7: : StudentId.java */
package chapt10;
public class StudentId implements Comparator<Student> {
public int compare(Student one, Student two) {
return two.getIdStudent() - one.getIdStudent();
}
}
id StudentId:
Collections.sort(p, StudentId.class. newInstance ());
, .
Deque
Deque , , . , . . , - (null false ). Deque, . .
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Deque. addFirst(), addLast() . add() Queue addLast() Deque.
/* # 8: Deque: DequeRunner.java */
package chapt10;
import java.util.*;
public class DequeRunner {
public static void printDeque(Deque<?> d){
for (Object de: d)
System. out. println(de + "; ");
}
public static void main(String[] args) {
Deque<String> deque = new ArrayDeque<String>();
deque.add(new String("5"));
deque.addFirst("A");
//deque.addLast(new Integer(5));//
System. out. println(deque.peek());
System. out. println("Before:");
printDeque (deque);
deque.pollFirst();
System. out. println(deque.remove(5));
System. out. println("After:");
printDeque (deque);
}
}
:
A
Before:
A;
5;
False
After:
5;
Set<E> , . SortedSet<E> Set<E> , , . NavigableSet .
. 10.2.
HashSet<E>
AbstractSet<E> Set<E>, - . (-) , . . -, - .
:
HashSet()
HashSet(Collection <? extends E> c)
HashSet(int capacity)
HashSet(int capacity, float loadFactor), capacity -.
/* # 9: : DemoHashSet.java */
package chapt10;
import java.util.*;
import java.io.*;
public class DemoHashSet {
public static void main(String[] args) {
HashSet<String> words = new HashSet<String>(100);
// LinkedHashSet TreeSet
long callTime = System. nanoTime ();
try {
BufferedReader in =
new BufferedReader(
new FileReader("c://pushkin.txt"));
String line = "";
while ((line = in.readLine())!= null) {
StringTokenizer tokenizer =
new StringTokenizer(line,
" (){}[]<>#*!?.,:;-\'\"/");
while (tokenizer.hasMoreTokens()) {
String word = tokenizer.nextToken();
words.add(word.toLowerCase());
}
}
} catch (IOException e) {
System. err. println(e);
}
Iterator<String> it = words.iterator();
while (it.hasNext())
System. out. println(it.next());
long totalTime = System. nanoTime ()- callTime;
System. out. println(" : " + words.size()
+ ", " + totalTime + " ");
}
}
TreeSet<E> . . , Comparator Comparable. , -, , .
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|
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:
TreeSet()
TreeSet(Collection <? extends E> c)
TreeSet(Comparator <? super E> c)
TreeSet(SortedSet <E> s)
TreeSet<E> ( ) E first() E last(). SortedSet<E> subSet(E from, E to),
SortedSet<E> tailSet(E from)
SortedSet<E> headSet(E to)
.
Comparator <? super E> comparator()
Comparator, null, .
/* # 10: : DemoTreeSet.java */
package chapt10;
import java.util.*;
public class DemoTreeSet {
public static void main(String[] args) {
ArrayList<String> c = new ArrayList<String>();
boolean b;
for (int i = 0; i < 6; i++)
c.add((int) (Math. random () * 71) + "Y ");
System. out. println(c + "");
TreeSet<String> set = new TreeSet<String>(c);
System. out. println(set + "");
b = set.add("5 Element"); // (b=true)
b = set.add("5 Element"); // (b=false)
//
System. out. println(set + "add");
System. out. println(set.comparator()); //null!!!
//
System. out. println(set.last() + " "
+ set.first());
}
}
:
[44Y, 56Y, 49Y, 26Y, 49Y, 2Y ]
[2Y, 26Y, 44Y, 49Y, 56Y ]
[2Y, 26Y, 44Y, 49Y, 5 Element, 56Y ]add
Null
Y 2Y
. . . , , , comparator() null.
String StringBuilder
StringBuffer, TreeSet . StringBuilder Comparable<T> :
/* # 11: , TreeSet: Message.java */
package chapt10;
import java.util.*;
public class Message implements Comparable<Message> {
private StringBuilder str;
private int idSender;
public Message(StringBuilder s, int id) {
super ();
this. str = s;
idSender = id;
}
public String getStr() {
return str.toString();
}
public int getId() {
return idSender;
}
public int compareTo(Message a0) {
return (idSender - a0.getId());
}
}
.
EnumSet<E extends Enum<E>> AbstractSet. enum. enum, . , long. . , .
. EnumSet<E> noneOf(Class<E> elemType) c ,
allOf(Class<E> elementType) , . of(E first, E... rest) , .
complementOf(EnumSet<E> s) , , . range(E from, E to) , , . null NullPointerException.
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/* # 12: c enum-: UseEnumSet.java */
package chapt10;
import java.util.EnumSet;
enum Faculty{ FFSM, MMF, FPMI, FMO, GEO }
public class UseEnumSet {
public static void main(String[] args) {
/* set1 enum ,
*/
EnumSet <Faculty> set1 =
EnumSet. range (Faculty. MMF, Faculty. FMO);
/* set2 ,
set1*/
EnumSet <Faculty> set2 =
EnumSet. complementOf (set1);
System. out. println(set1);
System. out. println(set2);
}
}
:
[MMF, FPMI, FMO]
[FFSM, GEO]
NavigableSet. first() . subSet(E fromElement, E toElement) , fromElement toElement, . headSet(E element) tailSet(E element, boolean inclusive) , element . inclusive true, .
/* # 13: c NavigableSet: NavigableSetTest.java */
package chapt10;
import java.util.*;
public class NavigableSetTest {
public static void main(String[] args) {
HashSet<String> city = new HashSet<String>();
city.add("Minsk");
city.add("Mosow");
city.add("Polotsk");
city.add("Brest");
NavigableSet<String> ns = new TreeSet<String>(city);
System. out. println("All: " + ns);
System. out. println("First: " + ns.first());
System. out. println("Between Minsk and Polotsk: "
+ ns.subSet("Minsk","Polotsk"));
System. out. println("Before Minsk: "
+ ns.headSet("Minsk"));
System. out. println("After Minsk: "
+ ns.tailSet("Minsk", false));
}
}
:
All: [Brest, Minsk, Mosow, Polotsk]
First: Brest
Between Minsk and Polotsk: [Minsk, Mosow]
Before Minsk: [Brest]
After Minsk: [Mosow, Polotsk]
, -. () , . - hashCode() equals() . , null.
:
AbstractMap<K,V> Map<K,V>;
HashMap<K,V> AbstractMap<K,V>, -, -;
TreeMap<K,V> AbstractMap<K,V>, , .
WeakHashMap<K,V> , .
LinkedHashMap<K,V> . , - .
. 10.3.
IdentityHashMap<K,V> - - System.identityHashCode() , hashCode(), .
:
Map<K,V> ;
Map.Entry<K,V> -;
SortedMap<K,V> ;
NavigableMap<K,V> .
|
|
|
Map<K,V> :
void clear() ;
boolean containsKey(Object key) true, key ;
boolean containsValue(Object value) true, value ;
Set<Map.Entry<K,V>> entrySet() , ;
Set<K> keySet() ;
V get(Object obj) , obj;
V put(K key, V value) key value . . ;
void putAll(Map <? extends K,? extends V> t) t ;
V remove(Object key) - key;
Collection<V> values() , .
Map.Entry<K,V> :
K getKey() ;
V getValue() ;
V setValue(V obj) obj .
-
.
/* # 14: - :
DemoHashMap.java */
package chapt10;
import java.util.*;
public class DemoHashMap {
public static void main(String[] args){
HashMap<Integer, String> hm =
new HashMap<Integer, String>(5);
for (int i = 11; i < 15; i++)
hm.put(i, i + "EL");
System. out. println(hm);
hm.put(12, "14EL");
System. out. println(hm + " ");
String a = hm.get(12);
System. out. println(a + " - '12'");
/* -
Map.Entry<K,V> */
Set<Map.Entry<Integer, String>> setvalue =
hm.entrySet();
System. out. println(setvalue);
Iterator<Map.Entry<Integer, String>> i =
setvalue.iterator();
while (i.hasNext()) {
Map.Entry<Integer, String> me = i.next();
System. out. print(me.getKey()+": ");
System. out. println(me.getValue());
}
}
}
{13=13EL, 14=14EL, 12=12EL, 11=11EL}
{13=13EL, 14=14EL, 12=14EL, 11=11EL}
14EL - '12'
[13=13EL, 14=14EL, 12=14EL, 11=11EL]
EL
EL
EL
