Java中的 LinkedBlockingDeque push() 方法
LinkedBlockingDeque的push(E e)方法将元素推送到此双端队列表示的堆栈上。如果有空格,它将参数中传递的元素插入到 Deque 的前面。如果 LinkedBlockingDeque 容量受限且没有空间可插入,则返回IllegalStateException 。该函数类似于 addFirst() 的函数。
句法:
public void push(E e)
参数:此方法接受一个强制参数e ,它是要插入到 LinkedBlockingDeque 前面的元素。
返回:此方法不返回任何内容。
例外:
- IllegalStateException : 如果此时由于容量限制无法添加元素
- NullPointerException : 如果指定元素为 null
下面的程序说明了 LinkedBlockingDeque 的 push() 方法:
方案一:
// Java Program Demonstrate push()
// method of LinkedBlockingDeque
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
public class GFG {
public static void main(String[] args)
throws IllegalStateException
{
// create object of LinkedBlockingDeque
LinkedBlockingDeque LBD
= new LinkedBlockingDeque();
// Add numbers to end of LinkedBlockingDeque
LBD.push(7855642);
LBD.push(35658786);
LBD.push(5278367);
LBD.push(74381793);
// before removing print queue
System.out.println("Linked Blocking Deque: " + LBD);
}
}
输出:
Linked Blocking Deque: [74381793, 5278367, 35658786, 7855642]
方案二:
// Java Program Demonstrate push()
// method of LinkedBlockingDeque
// when it is Full
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
public class GFG {
public static void main(String[] args)
throws IllegalStateException
{
// create object of LinkedBlockingDeque
// size of list
LinkedBlockingDeque LBD
= new LinkedBlockingDeque(3);
// Add numbers to end of LinkedBlockingDeque
LBD.push(7855642);
LBD.push(35658786);
LBD.push(5278367);
// it is full
LBD.push(74381793);
// before removing print queue
System.out.println("Linked Blocking Deque: " + LBD);
}
}
输出:
Exception in thread "main" java.lang.IllegalStateException: Deque full
at java.util.concurrent.LinkedBlockingDeque.addFirst(LinkedBlockingDeque.java:326)
at java.util.concurrent.LinkedBlockingDeque.push(LinkedBlockingDeque.java:770)
at GFG.main(GFG.java:23)
方案 3:
// Java Program Demonstrate push()
// method of LinkedBlockingDeque
// when null is inserted
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
public class GFG {
public static void main(String[] args)
throws IllegalStateException
{
// create object of LinkedBlockingDeque
LinkedBlockingDeque LBD
= new LinkedBlockingDeque();
// Add numbers to end of LinkedBlockingDeque
LBD.push(7855642);
LBD.push(35658786);
LBD.push(5278367);
// NULL
LBD.push(null);
// before removing print queue
System.out.println("Linked Blocking Deque: " + LBD);
}
}
输出:
Exception in thread "main" java.lang.NullPointerException
at java.util.concurrent.LinkedBlockingDeque.offerFirst(LinkedBlockingDeque.java:342)
at java.util.concurrent.LinkedBlockingDeque.addFirst(LinkedBlockingDeque.java:325)
at java.util.concurrent.LinkedBlockingDeque.push(LinkedBlockingDeque.java:770)
at GFG.main(GFG.java:23)
参考: https: Java/util/concurrent/LinkedBlockingDeque.html#push(E)