JMeter5.1核心类ValueReplacer源码分析

    // CompoundFunction类
    private final CompoundVariable masterFunction = new CompoundVariable();

    // 变量列表
    private Map<String, String> variables = new HashMap<>();

    public ValueReplacer() {
    }

    public ValueReplacer(TestPlan tp) {
        setUserDefinedVariables(tp.getUserDefinedVariables());
    }

    boolean containsKey(String k){
        return variables.containsKey(k);
    }

    public void setUserDefinedVariables(Map<String, String> variables) {
        this.variables = variables;
    }

    private void setProperties(TestElement el, Collection<JMeterProperty> newProps) {
        // 清除原来的JMeterProperty类属性
        el.clear();
        for (JMeterProperty jmp : newProps) {
            // 重新赋值
            el.setProperty(jmp);
        }
    }

    public void replaceValues(TestElement el) throws InvalidVariableException {
        // 调用ReplaceStringWithFunctions类对TestElement类的JMeterProperty属性进行替换
        Collection<JMeterProperty> newProps = replaceValues(el.propertyIterator(), new ReplaceStringWithFunctions(masterFunction,
                variables));
        setProperties(el, newProps);
    }

    private Collection<JMeterProperty> replaceValues(PropertyIterator iter, ValueTransformer transform) throws InvalidVariableException {
        List<JMeterProperty> props = new LinkedList<>();
        while (iter.hasNext()) {
            JMeterProperty val = iter.next();
            if (log.isDebugEnabled()) {
                log.debug("About to replace in property of type: {}: {}", val.getClass(), val);
            }       
            if (val instanceof StringProperty) {
                // Must not convert TestElement.gui_class etc
                if (!val.getName().equals(TestElement.GUI_CLASS) &&
                        !val.getName().equals(TestElement.TEST_CLASS)) {
                    // 参数替换
                    val = transform.transformValue(val);
                    log.debug("Replacement result: {}", val);
                }
            } else if (val instanceof NumberProperty) {
                val = transform.transformValue(val);
                log.debug("Replacement result: {}", val);
            } else if (val instanceof MultiProperty) {
                MultiProperty multiVal = (MultiProperty) val;
                // 递归调用
                Collection<JMeterProperty> newValues = replaceValues(multiVal.iterator(), transform);
                multiVal.clear();
                for (JMeterProperty jmp : newValues) {
                    multiVal.addProperty(jmp);
                }
                log.debug("Replacement result: {}", multiVal);
            } else {
                log.debug("Won't replace {}", val);
            }
            props.add(val);
        }
        return props;
    }