aop_time_cost

using ASM to calculate functions' time costs.

#How to Use

Just add dependiencies:

	<dependencies>
		<!-- https://mvnrepository.com/artifact/org.ow2.asm/asm -->
		<dependency>
			<groupId>org.ow2.asm</groupId>
			<artifactId>asm</artifactId>
			<version>5.1</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.ow2.asm/asm-commons -->
		<dependency>
			<groupId>org.ow2.asm</groupId>
			<artifactId>asm-commons</artifactId>
			<version>5.1</version>
		</dependency>
		<dependency>
    			<groupId>cn.edu.tsinghua</groupId>
    			<artifactId>aopTimeCost</artifactId>
    			<version>0.0.2</version>
		</dependency>
	</dependencies>

Then, compile cn.edu.tsinghua.aop package and src/main/resources/META-INF/MANIFEST.MF as a jar (or add the jar if I publish it in official Maven Repo). I suppose the jar name is aopTimeCost.jar, and the jar is on /Users/yourname/Desktop/aopTimeCost.jar.

Then, find the file path of the jar aopTimeCost-0.0.2.jar (normally it is at your local maven repository: ~/.m2/repository/cn/edu/tsinghua/aopTimeCost/0.0.2/aopTimeCost-0.0.2.jar). Remember this path, I will use to reference it.

Thirdly, if you are using Eclipse, then set the Run Configuration for your Main class: VM arguments: -javaagent:<the aop jar file path>. e.g., VM arguments: -javaagent:/Users/jixuan/.m2/repository/cn/edu/tsinghua/aopTimeCost/0.0.2/aopTimeCost-0.0.2.jar

If you are using Idea, see you tomorrow. (The configuration should be similar, I think.)

Now you can enjoy the powerful of this tool:

For example, you have a class like this:

public class Test {
  public void doanything() {
    System.out.print("Hello World.");
  }
}

And you want to know how many times that the function doanything is called and the total time cost of the fucntion, just modify your code like this:

public class Test {
  @Cost
  public void doanything() {
    System.out.print("Hello World.");
  }
}

It is almost done! By default, I disable the statistics information. To enable the information, There are two options:

1. using the code to enable the statistics:

CostResult.getInstance().startRecord();

and using the code to disable the staticstics again:

CostResult.getInstance().stopRecord();

2. using JMX (e.g., jconsole), the MBean is performance.CostResult, you can click startRecord() to enable it and click stopRecord() to disable the information.

Now it is time to see the result:

If you want to know the statistics information, just open jconsole and find performance.CostResult MBean, these functions are useful:

• getTimes(className, methodName), return the times that the method is called. Notice that, suppose your class is cn.edu.tsinghua.hxd.Test, the the className is cn/edu/tsinghua/hxd/Test.

• getTotalTimeCost(className, methodName), return the total time cost that the method spends. Notice that, suppose your class is cn.edu.tsinghua.hxd.Test, the the className is cn/edu/tsinghua/hxd/Test.

• sortTimes2String() return the called times of all the functions that you are interested. The result is sorted.

• sortTimeCosts2String() return the total time costs for each functions that you are interested. The result is sorted.

• sortTimes, similar with sortTimes2String() while the result is List<IntPair>, you can only call this function by coding rather than jconsole.

• sortTimeCosts2String() , similar with sortTimeCosts2String() while the result is List<LongPair>, you can only call this function by coding rather than jconsole.

• startRecord(), enable the record.

• stopRecord(), disable the record and clear the previous results.