Java中的 LinkedBlockingDeque peekLast() 方法
LinkedBlockingDeque 的peekLast ()方法返回 Deque 容器中的最后一个元素,但不会删除它。如果容器为空,则返回null 。
句法:
public E peekLast()
参数:此方法不接受任何参数。
返回:如果容器不为空,则此方法返回 Deque 容器中的最后一个元素。如果容器为空,则返回 false。
下面的程序说明了 LinkedBlockingDeque 的 peekLast() 方法:
方案一:
// Java Program Demonstrate peekLast()
// method of LinkedBlockingDeque
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create object of LinkedBlockingDeque
LinkedBlockingDeque LBD
= new LinkedBlockingDeque();
// Add numbers to end of LinkedBlockingDeque
LBD.addFirst(7855642);
LBD.addFirst(35658786);
LBD.addFirst(5278367);
LBD.addFirst(74381793);
// Print the queue
System.out.println("Linked Blocking Deque: " + LBD);
System.out.println("Front element in Deque: " + LBD.peekLast());
}
}
输出:
Linked Blocking Deque: [74381793, 5278367, 35658786, 7855642]
Front element in Deque: 7855642
方案二:
// Java Program Demonstrate peekLast()
// method of LinkedBlockingDeque
// when Deque is empty
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create object of LinkedBlockingDeque
LinkedBlockingDeque LBD
= new LinkedBlockingDeque();
// Add numbers to end of LinkedBlockingDeque
LBD.add(7855642);
LBD.add(35658786);
LBD.add(5278367);
LBD.add(74381793);
// Print the queue
System.out.println("Linked Blocking Deque: " + LBD);
// empty deque
LBD.clear();
System.out.println("Front element in Deque: " + LBD.peekLast());
}
}
输出:
Linked Blocking Deque: [7855642, 35658786, 5278367, 74381793]
Front element in Deque: null
参考: https: Java/util/concurrent/LinkedBlockingDeque.html#peekLast()