一直好奇JUnit里面@Test的实现，搜了不少网页，大部分都是讲的使用方式，很少有人去讲解实现原理。自己看源码看了半天也没有找到头绪。
索性自己摸索着实现了一套类似的效果，下一步准备应用在已经完成的仿真测试上，虽然很初级，但也算一个框架了。
1 定义注解
//Simulation.java
package com.sigh.test;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Created by sigh on 2015/6/10.
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE})
public @interface Simulation {
}
//Run.java
package com.sigh.test;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Created by sigh on 2015/6/10.
*/
//类似junit的@Test效果
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface Run {
//该操作发生的概率
double rate() default 0;
}
//Report.java
package com.sigh.test;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Created by sigh on 2015/6/10.
*/
//在所有@Run运行完之后报告结果
@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.METHOD})
public @interface Report {
}
这三个注解就是对外提供的全部接口了。
2 测试类
//First.java
package com.sigh.test;
import org.springframework.stereotype.Service;
/**
* Created by sigh on 2015/6/9.
*/
@Simulation
@Service
public class First {
@Run(rate = 0.5)
boolean run() {
System.out.println("first");
return true;
}
@Report
void report() {
System.out.println("report first");
}
}
//Second.java
package com.sigh.test;
import org.springframework.stereotype.Service;
/**
* Created by sigh on 2015/6/9.
*/
@Simulation
@Service
public class Second {
@Run(rate = 0.5)
long doWork() {
System.out.println("second");
return 3;
}
@Report
void display() {
System.out.println("display second");
}
}
比较特殊的是rate，用于提供一种概率性的运行方式。
3 框架核心代码
package com.sigh.test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Created by sigh on 2015/6/10.
*/
public class SimulationFacade {
interface RunMethod {
void run();
double getRate();
}
interface ReportMethod {
void report();
}
private static List<Object> classes = null;
private static List<RunMethod> runMethods = null;
private static List<ReportMethod> reportMethods = null;
private final static int MAX_OPERATION_TIMES = 100;
static {
classes = new ArrayList<>();
ApplicationContext applicationContext = new FileSystemXmlApplicationContext("src/spring-config.xml");
Map<String, Object> beanNames = applicationContext.getBeansWithAnnotation(Simulation.class);
for (Object o : beanNames.values()) {
classes.add(o);
}
System.out.println(beanNames);
runMethods = new ArrayList<RunMethod>();
reportMethods = new ArrayList<ReportMethod>();
for (final Object o : classes) {
Method[] methods = o.getClass().getDeclaredMethods();
for (final Method method : methods) {
if (method.isAnnotationPresent(Run.class)) {
runMethods.add(new RunMethod() {
@Override
public void run() {
try {
method.invoke(o);
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
@Override
public double getRate() {
return method.getAnnotation(Run.class).rate();
}
});
} else if (method.isAnnotationPresent(Report.class)) {
reportMethods.add(new ReportMethod() {
@Override
public void report() {
try {
method.invoke(o);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
});
}
}
}
}
public void run() {
double rate = Math.random();
for (RunMethod method : runMethods) {
if (rate <= method.getRate()) {
method.run();
break;
} else {
rate -= method.getRate();
}
}
}
public void report() {
for (ReportMethod method : reportMethods) {
method.report();
}
}
public static class MulTiThreadSimulation {
private final static int THREAD_NUM = 10;
SimulationFacade simulationFacade = new SimulationFacade();
static AtomicInteger operationTimes = new AtomicInteger(0);
public void run() {
List<Thread> threadList = new ArrayList<Thread>();
for (int i = 0; i < THREAD_NUM; i++) {
Thread thread = new Thread(new Runnable() {
@Override public void run() {
while (operationTimes.getAndIncrement() < SimulationFacade.MAX_OPERATION_TIMES) {
try {
//仿真测试
simulationFacade.run();
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
thread.start();
threadList.add(thread);
}
for (Thread thread : threadList) {
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public void report() {
simulationFacade.report();
}
}
public static void main(String[] args) throws InvocationTargetException, IllegalAccessException, InstantiationException {
MulTiThreadSimulation mulTiThreadSimulation = new MulTiThreadSimulation();
mulTiThreadSimulation.run();
mulTiThreadSimulation.report();
}
}
基本的思路也相对比较清晰，所以也没有太多需要解释的地方。
java的内部类确实有很多很有意思的地方，许多地方现在想来还是有些复杂。估计还需要一段时间来慢慢理解java的内存模型了。
