jmeter系列五(Config配置元素)

今天研究的核心元素是Config

同样的道理在jmeter中每个testelement元素都对应着他的gui，Config也不例外，可以定位到包org.apache.jmeter.config和org.apache.jmeter.config.gui

包下面的类全部都是有关于Config这个元素,Config的元素的界面使用到了Jmete的两种界面策略（用到了TestBean和继承AbstractJMeterGuiComponent的实现方式）

前面分析了AbstractJMeterGuiComponent,TestBean后面会独立开篇分析

Config元素的TestElement的接口

package org.apache.jmeter.config;

public interface ConfigElement extends Cloneable {

    /**
     * Add a configuration element to this one. This allows config elements to
     * combine and give a "layered" effect. For example,
     * HTTPConfigElements have properties for domain, path, method, and
     * parameters. If element A has everything filled in, but null for domain,
     * and element B is added, which has only domain filled in, then after
     * adding B to A, A will have the domain from B. If A already had a domain,
     * then the correct behavior is for A to ignore the addition of element B.
     *
     * @param config
     *            the element to be added to this ConfigElement
     */
    void addConfigElement(ConfigElement config);

    /**
     * If your config element expects to be modified in the process of a test
     * run, and you want those modifications to carry over from sample to sample
     * (as in a cookie manager - you want to save all cookies that get set
     * throughout the test), then return true for this method. Your config
     * element will not be cloned for each sample. If your config elements are
     * more static in nature, return false. If in doubt, return false.
     *
     * @return true if the element expects to be modified over the course of a
     *         test run
     */
    boolean expectsModification();

    Object clone();
}

一般的实现

public class ConfigTestElement extends AbstractTestElement implements Serializable, ConfigElement {
    private static final long serialVersionUID = 240L;

    public static final String USERNAME = "ConfigTestElement.username";

    public static final String PASSWORD = "ConfigTestElement.password";

    public ConfigTestElement() {
    }

    @Override
    public void addTestElement(TestElement parm1) {
        if (parm1 instanceof ConfigTestElement) {
            mergeIn(parm1);
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void addConfigElement(ConfigElement config) {
        mergeIn((TestElement) config);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean expectsModification() {
        return false;
    }
}

Config的所有TestElement都会继承这个实现比如Arguments，CSVDataSet等

---------------------------------------------------------------现在是Config元素在engine中的执行情况----------------------------------------------------------------

PreCompiler类涉及到ConfigTestElement的操作，PreCompiler类中的AddNode方法的中涉及到Arguments的代码

if (node instanceof Arguments) {
            ((Arguments)node).setRunningVersion(true);
            Map<String, String> args = ((Arguments) node).getArgumentsAsMap();
            replacer.addVariables(args);
            JMeterContextService.getContext().getVariables().putAll(args);
        }

总之，Config元素的作用就是设置参数将其放在JMeterContext中，供后面的JMeter元素使用