Java中的LinkedBlockingDeque offer()方法

LinkedBlockingDeque 的 offer(E e) 方法将传递的元素插入到Deque的末尾。如果容器的容量超过了限制，则不像add()和addFirst()函数一样抛出异常。

语法:

public boolean offer(E e)

参数: 此方法接受一个必需的参数 e ，它是要插入到LinkedBlockingDeque末尾的元素。

返回值: 如果已插入元素，则此方法返回true，否则返回false。

下面的程序说明了LinkedBlockingDeque的offer()方法：

程序1:

// Java程序演示LinkedBlockingDeque offer()方法
 
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
 
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
 
        //创建LinkedBlockingDeque对象
        LinkedBlockingDeque<Integer> LBD
            = new LinkedBlockingDeque<Integer>(4);
 
        //将数字添加到LinkedBlockingDeque的末尾
        LBD.offer(7855642);
        LBD.offer(35658786);
        LBD.offer(5278367);
        LBD.offer(74381793);
 
        //无法插入
        LBD.offer(10);
 
        //无法插入，因此返回false
        if (!LBD.offer(10))
            System.out.println("The element 10 cannot be inserted"+
                                           " as capacity is full");
 
        //移除前打印队列
        System.out.println("Linked Blocking Deque: " + LBD);
    }
}

The element 10 cannot be inserted as capacity is full
Linked Blocking Deque: [7855642, 35658786, 5278367, 74381793]

程序2:

// Java程序演示LinkedBlockingDeque offer()方法
 
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
 
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
 
        //创建LinkedBlockingDeque对象
        LinkedBlockingDeque<String> LBD
            = new LinkedBlockingDeque<String>(4);
 
        //将数字添加到LinkedBlockingDeque的末尾
        LBD.offer("abc");
        LBD.offer("gopu");
        LBD.offer("geeks");
        LBD.offer("richik");
 
        //无法插入
        LBD.offer("hii");
 
        //无法插入，因此返回false
        if (!LBD.offer("hii"))
            System.out.println("The element 'hii' cannot be inserted"+
                                              " as capacity is full");
 
        //移除前打印队列
        System.out.println("Linked Blocking Deque: " + LBD);
    }
}

The element 'hii' cannot be inserted as capacity is full
Linked Blocking Deque: [abc, gopu, geeks, richik]

参考: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/LinkedBlockingDeque.html#offer(E)