Package g1101_1200.s1114_print_in_order

Class Foo

java.lang.Object

g1101_1200.s1114_print_in_order.Foo

public class Foo
extends Object

1114 - Print in Order.<p>Easy</p> <p>Suppose we have a class:</p> <p>public class Foo { public void first() { print(&ldquo;first&rdquo;); } public void second() { print(&ldquo;second&rdquo;); } public void third() { print(&ldquo;third&rdquo;); } }</p> <p>The same instance of <code>Foo</code> will be passed to three different threads. Thread A will call <code>first()</code>, thread B will call <code>second()</code>, and thread C will call <code>third()</code>. Design a mechanism and modify the program to ensure that <code>second()</code> is executed after <code>first()</code>, and <code>third()</code> is executed after <code>second()</code>.</p> <p><strong>Note:</strong></p> <p>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&rsquo; comprehensiveness.</p> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> nums = [1,2,3]</p> <p><strong>Output:</strong> &ldquo;firstsecondthird&rdquo;</p> <p><strong>Explanation:</strong> 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(). &ldquo;firstsecondthird&rdquo; is the correct output.</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> nums = [1,3,2]</p> <p><strong>Output:</strong> &ldquo;firstsecondthird&rdquo;</p> <p><strong>Explanation:</strong> The input [1,3,2] means thread A calls first(), thread B calls third(), and thread C calls second(). &ldquo;firstsecondthird&rdquo; is the correct output.</p> <p><strong>Constraints:</strong></p> <ul> <li><code>nums</code> is a permutation of <code>[1, 2, 3]</code>.</li> </ul>

Constructor Summary

Constructors

Constructor	Description
Foo()

Method Summary

Modifier and Type	Method	Description
void	first(Runnable printFirst)
void	second(Runnable printSecond)
void	third(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(Runnable printFirst)

second

public void second(Runnable printSecond)

third

public void third(Runnable printThird)