import cn.hutool.core.util.RuntimeUtil;
import com.sun.xml.internal.bind.v2.runtime.reflect.opt.FieldAccessor_Ref;
import org.junit.Test;
import org.junit.rules.RunRules;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Proxy;

/**
 * @author Summerday
 */
public class RuntimeTest {


 @Test
 public void testExec(){
 Process process = null;
 try {
 // 打开记事本
 process = Runtime.getRuntime().exec("notepad");
 Thread.sleep(2000);
 } catch (IOException | InterruptedException e) {
 e.printStackTrace();
 }finally {
 if(process != null){
 process.destroy();
 }
 }
 }

 @Test
 public void testAvailableProcessors(){
 System.out.println(Runtime.getRuntime().availableProcessors());
 }

 @Test
 public void testFreeMemory(){
 Runtime r = Runtime.getRuntime();
 System.out.println("处理器个数: " + r.availableProcessors());
 System.out.println("最大内存 : " + r.maxMemory());
 System.out.println("总内存 : " + r.totalMemory());
 System.out.println("剩余内存: " + r.freeMemory());
 System.out.println("最大可用内存: " + getUsableMemory());

 for(int i = 0; i < 10000; i ++){
 new Object();
 }

 System.out.println("创建10000个实例之后, 剩余内存: " + r.freeMemory());
 r.gc();
 System.out.println("gc之后, 剩余内存: " + r.freeMemory());

 }
 /**
 * 获得JVM最大可用内存 = 最大内存-总内存+剩余内存
 */
 private long getUsableMemory() {
 Runtime r = Runtime.getRuntime();
 return r.maxMemory() - r.totalMemory() + r.freeMemory();
 }


 @Test
 public void testAddShutdownHook() throws InterruptedException {
 Runtime.getRuntime().addShutdownHook(new Thread(()-> System.out.println("programming exit!")));
 System.out.println("sleep 3s");
 Thread.sleep(3000);
 System.out.println("over");
 }


 @Test
 public void testRemoveShutdownHook() throws InterruptedException {
 Thread thread = new Thread(()-> System.out.println("programming exit!"));
 Runtime.getRuntime().addShutdownHook(thread);
 System.out.println("sleep 3s");
 Thread.sleep(3000);
 Runtime.getRuntime().removeShutdownHook(thread);
 System.out.println("over");
 }

 @Test
 public void testExit(){
 Runtime.getRuntime().exit(0);
 //下面这段 无事发生
 System.out.println("Program Running Check");
 }

 @Test
 public void testHalt(){
 Runtime r = Runtime.getRuntime();
 r.halt(0);
 System.out.println("process is still running");
 }


}