Package g1101_1200.s1114_print_in_order

Class Foo

java.lang.Object
g1101_1200.s1114_print_in_order.Foo
public class Foo extends java.lang.Object
1114 - Print in Order.

Easy

Suppose we have a class:

public class Foo { public void first() { print(“first”); } public void second() { print(“second”); } public void third() { print(“third”); } }

The same instance of Foo will be passed to three different threads. Thread A will call first(), thread B will call second(), and thread C will call third(). Design a mechanism and modify the program to ensure that second() is executed after first(), and third() is executed after second().

Note:

We do not know how the threads will be scheduled in the operating system, even though the numbers in the input seem to imply the ordering. The input format you see is mainly to ensure our tests’ comprehensiveness.

Example 1:

Input: nums = [1,2,3]

Output: “firstsecondthird”

Explanation: There are three threads being fired asynchronously. The input [1,2,3] means thread A calls first(), thread B calls second(), and thread C calls third(). “firstsecondthird” is the correct output.

Example 2:

Input: nums = [1,3,2]

Output: “firstsecondthird”

Explanation: The input [1,3,2] means thread A calls first(), thread B calls third(), and thread C calls second(). “firstsecondthird” is the correct output.

Constraints:

  • nums is a permutation of [1, 2, 3].

  • Constructor Summary

    Constructors
    Constructor
    Description
    Foo()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    first(java.lang.Runnable printFirst)
     
    void
    second(java.lang.Runnable printSecond)
     
    void
    third(java.lang.Runnable printThird)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Foo

      public Foo()

  • Method Details

    • first

      public void first(java.lang.Runnable printFirst)

    • second

      public void second(java.lang.Runnable printSecond)

    • third

      public void third(java.lang.Runnable printThird)