极客教程Java LinkedBlockingQueue remainingCapacity()方法
LinkedBlockingQueue的 remainCapacity() 方法返回可以添加到LinkedBlockingQueue而不阻塞的元素数量。返回的容量有三种情况。
- 如果剩余容量为零，那么就没有更多的元素可以被添加到LinkedBlockingQueue中。
- 如果LinkedBlockingQueen的剩余容量等于队列的大小，那么没有元素可以从队列中删除，因为在这种情况下队列是空的。
- 在其他任何情况下，容量总是等于这个LinkedBlockinQueue的初始容量和这个LinkedBlockingQueue的当前大小之间的差值。
语法
public int remainingCapacity()
返回值： 该方法返回LinkedBlockingQueue的 剩余容量 。下面的程序说明了LinkedBlockingQueue类的remainingCapacity()方法：
程序1： 使用remainingCapacity()方法返回LinkedBlockingQueue的剩余容量，其中LinkedBlockingQueue包含名字的列表。
// Java Program Demonstrate remainingCapacity()
// method of LinkedBlockingQueue
import java.util.concurrent.LinkedBlockingQueue;
public class GFG {
public static void main(String[] args)
{
// define capacity of LinkedBlockingQueue
int capacityOfQueue = 7;
// create object of LinkedBlockingQueue
LinkedBlockingQueue<String> linkedQueue
= new LinkedBlockingQueue<String>(capacityOfQueue);
// Add element to LinkedBlockingQueue
linkedQueue.add("John");
linkedQueue.add("Tom");
linkedQueue.add("Clark");
linkedQueue.add("Kat");
// find remaining Capacity of linkedQueue
// using remainingCapacity() method
int remainingCapacity = linkedQueue.remainingCapacity();
// print result
System.out.println("Queue is " + linkedQueue);
// print head of queue
System.out.println("Remaining Capacity of Queue is "
+ remainingCapacity);
}
}
输出
Queue is [John, Tom, Clark, Kat]
Remaining Capacity of Queue is 3
程序2： 寻找包含雇员列表的LinkedBlockingQueue的剩余容量。
// Java Program Demonstrate peek()
// method of LinkedBlockingQueue
import java.util.concurrent.LinkedBlockingQueue;
public class GFG {
public void findPeek()
{
// define capacity of LinkedBlockingQueue
int capacityOfQueue = 7;
// create object of LinkedBlockingQueue
LinkedBlockingQueue<Employee> linkedQueue
= new LinkedBlockingQueue<Employee>(capacityOfQueue);
// Add element to LinkedBlockingQueue
Employee emp1 = new Employee("Ravi", "Tester", "39000");
Employee emp2 = new Employee("Sanjeet", "Manager", "98000");
// Add Employee Objects to linkedQueue
linkedQueue.add(emp1);
linkedQueue.add(emp2);
// add element and find remaining capacity
// follow same process again
// until the queue becomes full
while (linkedQueue.size() != 7) {
// adding emp2 again and again to queue
System.out.println("Adding employee is success "
+ linkedQueue.offer(emp2));
// find remaining capacity of linkedQueue
// using remainingCapacity() method
int remain = linkedQueue.remainingCapacity();
// print remaining capacity value
System.out.println("Remaining Capacity of list :"
+ remain);
}
}
// create an Employee Object with name,
// position and salary as an attribute
public class Employee {
public String name;
public String position;
public String salary;
Employee(String name, String position, String salary)
{
this.name = name;
this.position = position;
this.salary = salary;
}
@Override
public String toString()
{
return "Employee [name=" + name + ", position="
+ position + ", salary=" + salary + "]";
}
}
// Main Method
public static void main(String[] args)
{
GFG gfg = new GFG();
gfg.findPeek();
}
}
输出
Adding employee is success true
Remaining Capacity of list :4
Adding employee is success true
Remaining Capacity of list :3
Adding employee is success true
Remaining Capacity of list :2
Adding employee is success true
Remaining Capacity of list :1
Adding employee is success true
Remaining Capacity of list :0
参考资料: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/LinkedBlockingQueue.html#remainingCapacity-