ArrayList()
ArrayList(Collection <? extends E> c)
ArrayList(int capacity)
. List<E> , :
void add(int index, E element) element , index;
void addAll(int index, Collection<? extends E> c) , index;
E get(int index)
index;
int indexOf(Object ob) ;
E remove(int index) index;
E set(int index, E element) index, ;
List<E> subList(int fromIndex, int toIndex) .
, ArrayList<E> .
/* # 1: : DemoGeneric.java */
package by.bsu. chapt10;
import java.util.*;
public class DemoGeneric {
public static void main(String args[]) {
ArrayList<String> list = new ArrayList<String>();
// ArrayList<int> b = new ArrayList<int>(); //
list.add("Java"); /*
*/
list.add("Fortress");
String res = list.get(0); /*
*/
// list.add(new StringBuilder("C#") ); //
//
System. out. print(list);
}
}
:
[Java, Fortress]
, , list. .
, , .
/* # 2: (raw): UncheckCheck.java */
package by.bsu. chapt10;
import java.util.*;
public class UncheckCheck {
public static void main(String args[]) {
ArrayList list = new ArrayList(); //
list.add(71);
list.add(new Boolean("TruE"));
list.add("Java 1.6.0");
//
int i = (Integer)list.get(0);
boolean b = (Boolean)list.get(1);
String str = (String)list.get(2);
for (Object ob: list) {
System. out. println("list " + ob);
}
ArrayList<Integer> s = new ArrayList<Integer>();
s.add(71);
s.add(92);
// s.add("101");// : s
for (Integer ob: s) {
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System. out. println("int " + ob);
}
}
}
:
List 71
List true
List Java 1.6.0
Int 71
Int 92
, , .
Iterator . , .
/* # 3: : DemoIterator.java */
package by.bsu. chapt10;
import java.util.*;
public class DemoIterator {
public static void main(String[] args) {
ArrayList<Double> c =
new ArrayList<Double>(7);
System. out. println(" : "
+ a.isEmpty());
for (int i = 0;i < 10; i++) {
double z = new Random().nextGaussian();
c.add(z); //
}
//
for (Double d: c) {
System. out. printf("%.2f ",d);
}
int positiveNum = 0;
int size = c.size(); //
//
Iterator<Double> it = c.iterator();
//
while (it.hasNext()) {
//
if (it.next() > 0) {
positiveNum++;
} else {
it.remove(); //
}
}
System. out. printf("%n : %d ",
positiveNum);
System. out. printf("%n : %d ",
size - positiveNum);
System. out. println("\n ");
for (Double d: c) {
System. out. printf("%.2f ",d);
}
}
}
:
: true
0,69 0,33 0,51 -1,24 0,07 0,46 0,56 1,26 -0,84 -0,53
: 7
: 3
0,69 0,33 0,51 0,07 0,46 0,56 1,26
ListIterator<E>, . .
/* # 4: , : DemoListMethods.java */
package by.bsu. chapt10;
import java.util.*;
public class DemoListMethods {
public static void main(String[] args) {
ArrayList<Character> a =
new ArrayList<Character>(5);
for (char c = 'a'; c < 'h'; ++c) {
a.add(c);
}
char ch = 'a';
a.add(6, ch); // 6 >=8
System. out. println(a);
ListIterator<Character> it; //
it= a.listIterator(2); //
System. out. println(" "
+ it.nextIndex());
it.add('X'); //
System. out. println(a);
//
int index = a.lastIndexOf(ch); // a.indexOf(ch);
a.set(index, 'W'); //
System. out. println(a + " ");
if (a.contains(ch)) {
a.remove(a.indexOf(ch));
}
System. out. println(a + " " + ch);
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}
}
:
[a, b, c, d, e, f, a, g]
2
[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>: boolean offer(E o) , ; E element() , ; E peek() , , null , ; E poll() , null , ; E remove() .element() remove() peek() poll() , , .
/* # 5: : DemoLinkedList.java */
package by.bsu. 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());
}
}
:
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, .
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/* # 6: : UniqSortMark.java */
package by.bsu. 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()));
}
public boolean equals(Object ob){ /**/ }
}
package by.bsu. 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.
Student Student, StudentEnum:
public enum StudentEnum {
IDSTUDENT, MEANMARK
}
:
public class Student{ // Comparator
private int idStudent;
private float meanMark;
/* sortEnum
. setSortEnum() */
public static StudentEnum sortEnum =
StudentEnum. MEANMARK;
//...
}
, Comparator.
/* # 7: : StudentId.java */
package by.bsu.chapt10;
import java.util.Comparator;
public class StudentComparator
implements Comparator<Student> {
public int compare(Student one, Student two) {
switch (Student. sortEnum) {
case IDSTUDENT:
Return
(one.getIdStudent() - two.getIdStudent());
case MEANMARK:
Return
(int)(Math. ceil (two.getMark() - one.getMark()));
default: throw
new EnumConstantNotPresentException(
StudentEnum. class, Student. sortEnum. name());
}
}
public boolean equals(Object ob){ /**/ }
}
id sortEnum sort() StudentComparator:
Collections. sort (p, new StudentComparator());
Comparator equals() , compare() 0, equals() true. , equals() contains(Object o), java.util.Collection, , .
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Deque
Deque , , . , . . , - (null false ). Deque, . .
Deque. addFirst(), addLast() . add() Queue addLast() Deque.
/* # 8: Deque: DequeRunner.java */
package by.bsu.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 .
. 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 by.bsu.chapt10;
import java.io.*;
import java.util.*;
public class DemoHashSet {
public static void main(String[] args) {
HashSet<String> words =
new HashSet<String>(100);
long callTime = System. nanoTime ();
Scanner scan;
try {
scan = new Scanner(
new File("c://pushkin.txt"));
scan.useDelimiter("[^--]+");
while (scan.hasNext()) {
String word = scan.next();
words.add(word.toLowerCase());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Iterator<String> it = words.iterator();
while (it.hasNext()) {
System. out. println(it.next());
}
TreeSet<String> ts =
new TreeSet<String>(words);
System. out. println(ts);
long totalTime = System. nanoTime () - callTime;
System. out. println(" : "
+ words.size() + ", "
+ totalTime + " ");
}
}
TreeSet<E> . . , Comparator Comparable. , -, , .
:
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)
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.
Comparator <? super E> comparator()
Comparator, null, .
/* # 10: : DemoTreeSet.java */
package by.bsu.chapt10;
import java.util.*;
public class DemoTreeSet {
public static void main(String[] args) {
ArrayList<String> list = new ArrayList<String>();
boolean b;
for (int i = 0; i < 6; i++) {
list.add((int) (Math. random () * 71) + "Y ");
}
System. out. println(list + "");
TreeSet<String> set = new TreeSet<String>(list);
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 by.bsu.chapt10;
import java.util.*;
public class Message implements Comparable<Message> {
private StringBuilder str;
private int idSender;
public Message(StringBuilder s, int id) {
this. str = s;
idSender = id;
}
public String getStr() {
return str.toString();
}
public int getIdSender() {
return idSender;
}
public int compareTo(Message a0) {
return (idSender - a0.getIdSender());
}
public boolean equals(Object ob){ /**/ }
}
.
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.
/* # 12: c enum-: UseEnumSet.java */
package by.bsu.chapt10;
import java.util.EnumSet;
enum Faculty{ FFSM, MMF, FPMI, RFE, GEO }
public class UseEnumSet {
public static void main(String[] args) {
/* set1 enum ,
*/
EnumSet <Faculty> set1 =
EnumSet. range (Faculty. MMF, Faculty. RFE);
/* set2 ,
set1*/
EnumSet <Faculty> set2 =
EnumSet. complementOf (set1);
System. out. println(set1);
System. out. println(set2);
}
}
:
[MMF, FPMI, RFE]
[FFSM, GEO]
NavigableSet
NavigableSet<E>, Java SE 6, SortedSet . TreeSet<E> .
NavigableSet<E>:
.
Iterator iterator() ;
Iterator descendingIterator() ;
NavigableSet descendingSet() ;
E lower(E e) ;
E floor(E e) ;
E higher(E e) ;
E ceiling(E e) ;
E pollFirst() ;
E pollLast() ;
SortedSet<E> subSet(E fromElement, E toElement) , fromElement toElement, ;
NavigableSet subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) ;
, , , . fromElement toElement , fromInclusive toInclusive , . headSet , tailSet - . , .
