jmeter系列二(jmeter engine相关)

准备知识org.apache.jorphan.collections下的类，engine会使用到

Data类:模拟table存储数据

HashTree类：将对象以树形存储

HashTreeTraverser接口：实现了该接口的类可以获得HashTree中的存储的对象

SearchByClass类：实现了SearchByClass接口，engine会大量用到

第一篇讲的是界面相关的问题，当点击启动按钮jmeter将执行测试开始

这个toolbar是类org.apache.jmeter.gui.util.JMeterMenuBar实现的，看类中的makeRunMenu方法中代码

run_start = makeMenuItemRes("start", 'S', ActionNames.ACTION_START, KeyStrokes.ACTION_START);

private static JMenuItem makeMenuItemRes(String resource, int mnemonic, String actionCommand, KeyStroke keyStroke){
        JMenuItem menuItem = new JMenuItem(JMeterUtils.getResString(resource), mnemonic);
        menuItem.setName(resource);
        menuItem.setActionCommand(actionCommand);
        menuItem.setAccelerator(keyStroke);
        menuItem.addActionListener(ActionRouter.getInstance());
        return menuItem;
    }

menu的响应事件的类是ActionRouter，从前面文章可以知道在org.apache.jmeter.gui.action下找到类Start

public void doAction(ActionEvent e) {
        if (e.getActionCommand().equals(ActionNames.ACTION_START)) {
            popupShouldSave(e);
            startEngine(false);
        } else if (e.getActionCommand().equals(ActionNames.ACTION_START_NO_TIMERS)) {
            popupShouldSave(e);
            startEngine(true);
        } else if (e.getActionCommand().equals(ActionNames.ACTION_STOP)) {
            if (engine != null) {
                log.info("Stopping test");
                GuiPackage.getInstance().getMainFrame().showStoppingMessage("");
                engine.stopTest();
            }
        } else if (e.getActionCommand().equals(ActionNames.ACTION_SHUTDOWN)) {
            if (engine != null) {
                log.info("Shutting test down");
                GuiPackage.getInstance().getMainFrame().showStoppingMessage("");
                engine.askThreadsToStop();
            }
        }
    }

追踪到startEngine方法，其中经过一系列HashTree的相互转换和配置(前提看懂HashTree类的代码)，engine开始测试

runTest方法

public void runTest() throws JMeterEngineException {
        if (host != null){
            long now=System.currentTimeMillis();
            System.out.println("Starting the test on host " + host + " @ "+new Date(now)+" ("+now+")");
        }
        try {
            Thread runningThread = new Thread(this, "StandardJMeterEngine");
            runningThread.start();
        } catch (Exception err) {
            stopTest();
            throw new JMeterEngineException(err);
        }
    }

最后看到JmeterThread类中run方法，run方法大概流程

1.通过controller获取Sampler

2.执行preprocess(PreProcessor)

3.执行sampler(Sampler)

4.执行postprocess(PostProcessor)

5.调用SampleListeners(Visualizer)

6.调用controller的isDone方法判断是否loop

其中的这些元素都是通过HashTree来存储