Java by API/java.util/ListIterator — различия между версиями

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Версия 17:43, 31 мая 2010

ListIterator: add(T e)

  
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
public class Main{
  public static void main(String[] a) {
    List<String> list = new LinkedList<String>();
    list.add("A");
    list.add("B");
    list.add("C");
    list.add("D");
    ListIterator<String> iter = list.listIterator(list.size());
    while (iter.hasPrevious()) {
      System.out.println(iter.previous());
      iter.add("a");
      break;
    }
    System.out.println(list);
  }
}





ListIterator: hasNext()

  
/**
 *Output: 
Original contents of al: C A E B D F 
Modified list backwards: F+ D+ B+ E+ A+ C+ 
 */
import java.util.ArrayList;
import java.util.Iterator;
import java.util.ListIterator;
public class MainClass {
  public static void main(String args[]) {
    ArrayList<String> al = new ArrayList<String>();
    al.add("C");
    al.add("A");
    al.add("E");
    al.add("B");
    al.add("D");
    al.add("F");
    System.out.print("Original contents of al: ");
    Iterator<String> itr = al.iterator();
    while (itr.hasNext()) {
      String element = itr.next();
      System.out.print(element + " ");
    }
    System.out.println();
    ListIterator<String> litr = al.listIterator();
    while (litr.hasNext()) {
      String element = litr.next();
      litr.set(element + "+");
    }
    // Now, display the list backwards.
    System.out.print("Modified list backwards: ");
    while (litr.hasPrevious()) {
      String element = litr.previous();
      System.out.print(element + " ");
    }
  }
}





ListIterator: hasPrevious()

  
/**
 *Output: 
Original contents of al: C A E B D F 
Modified list backwards: F+ D+ B+ E+ A+ C+ 
 */
import java.util.ArrayList;
import java.util.Iterator;
import java.util.ListIterator;
public class MainClass {
  public static void main(String args[]) {
    ArrayList<String> al = new ArrayList<String>();
    al.add("C");
    al.add("A");
    al.add("E");
    al.add("B");
    al.add("D");
    al.add("F");
    System.out.print("Original contents of al: ");
    Iterator<String> itr = al.iterator();
    while (itr.hasNext()) {
      String element = itr.next();
      System.out.print(element + " ");
    }
    System.out.println();
    ListIterator<String> litr = al.listIterator();
    while (litr.hasNext()) {
      String element = litr.next();
      litr.set(element + "+");
    }
    // Now, display the list backwards.
    System.out.print("Modified list backwards: ");
    while (litr.hasPrevious()) {
      String element = litr.previous();
      System.out.print(element + " ");
    }
  }
}





ListIterator: next()

  
/**
 *Output: 
Original contents of al: C A E B D F 
Modified list backwards: F+ D+ B+ E+ A+ C+ 
 */
import java.util.ArrayList;
import java.util.Iterator;
import java.util.ListIterator;
public class MainClass {
  public static void main(String args[]) {
    ArrayList<String> al = new ArrayList<String>();
    al.add("C");
    al.add("A");
    al.add("E");
    al.add("B");
    al.add("D");
    al.add("F");
    System.out.print("Original contents of al: ");
    Iterator<String> itr = al.iterator();
    while (itr.hasNext()) {
      String element = itr.next();
      System.out.print(element + " ");
    }
    System.out.println();
    ListIterator<String> litr = al.listIterator();
    while (litr.hasNext()) {
      String element = litr.next();
      litr.set(element + "+");
    }
    // Now, display the list backwards.
    System.out.print("Modified list backwards: ");
    while (litr.hasPrevious()) {
      String element = litr.previous();
      System.out.print(element + " ");
    }
  }
}





ListIterator: nextIndex()

 
import java.util.ArrayList;
import java.util.ListIterator;
public class Main {
  public static void main(String[] args) {
    ArrayList<String> aList = new ArrayList<String>();
    aList.add("1");
    aList.add("2");
    aList.add("3");
    aList.add("4");
    aList.add("5");
    ListIterator<String> listIterator = aList.listIterator();
    System.out.println("Previous: " + listIterator.previousIndex());
    System.out.println("Next: " + listIterator.nextIndex());
    // advance current position by one using next method
    listIterator.next();
    System.out.println("Previous: " + listIterator.previousIndex());
    System.out.println("Next: " + listIterator.nextIndex());
  }
}





ListIterator: previous()

  
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
public class Main{
  public static void main(String[] a) {
    List<String> list = new LinkedList<String>();
    list.add("A");
    list.add("B");
    list.add("C");
    list.add("D");
    ListIterator<String> iter = list.listIterator(list.size());
    while (iter.hasPrevious()) {
      System.out.println(iter.previous());
      iter.add("a");
      break;
    }
    System.out.println(list);
  }
}





ListIterator: previousIndex()

 
import java.util.ArrayList;
import java.util.ListIterator;
public class Main {
  public static void main(String[] args) {
    ArrayList<String> aList = new ArrayList<String>();
    aList.add("1");
    aList.add("2");
    aList.add("3");
    aList.add("4");
    aList.add("5");
    ListIterator<String> listIterator = aList.listIterator();
    System.out.println("Previous: " + listIterator.previousIndex());
    System.out.println("Next: " + listIterator.nextIndex());
    // advance current position by one using next method
    listIterator.next();
    System.out.println("Previous: " + listIterator.previousIndex());
    System.out.println("Next: " + listIterator.nextIndex());
  }
}





ListIterator: remove()

 
import java.util.ArrayList;
import java.util.ListIterator;
public class Main {
  public static void main(String[] args) {
    ArrayList<String> aList = new ArrayList<String>();
    aList.add("1");
    aList.add("2");
    aList.add("3");
    aList.add("4");
    aList.add("5");
    // Get an object of ListIterator using listIterator() method
    ListIterator listIterator = aList.listIterator();
    listIterator.next();
    listIterator.next();
    // remove element returned by last next method
    listIterator.remove();
    for (String str: aList){
      System.out.println(str);
    }
  }
}





ListIterator: set(T e)

 
import java.util.ArrayList;
import java.util.ListIterator;
public class Main {
  public static void main(String[] args) {
    ArrayList<String> aList = new ArrayList<String>();
    aList.add("1");
    aList.add("2");
    aList.add("3");
    aList.add("4");
    aList.add("5");
    ListIterator<String> listIterator = aList.listIterator();
    listIterator.next();
    listIterator.set("100");
    for (String str : aList) {
      System.out.println(str);
    }
  }
}


Источник — «http://jexp.ru/index.php?title=Java_by_API/java.util/ListIterator&oldid=150»