feat: Enable usage of ${...} expressions for checkbox controls

[vlsi]

Description

The checkbox can be converted to an editable field by calling a context menu:

• right-click on the checkbox
• or press shift+F10

The editable box converts back to a checkbox if you select "true" or "false"

Fixes #1252
See #5761

Motivation and Context

Previously, JMeter did not allow users to use ${...} expressions for checkbox elements, however, there are cases when the checkbox should be customizable.
For instance, users might want to test different values enable keepalive setting, and currently it is not possible to configure it from a property file.

How Has This Been Tested?

Only manual testing for now :-/

Screenshots (if appropriate):

The second Run Thread Groups consecutively element is the new checkbox. It behaves like a usual checkbox.

However, it has a popup menu (right-click or shift+F10) so the users can convert it to an expression:

The editable element looks like an editable combobox:

Users can type up, down to select a predefined value, or they can select true or false in which case the element would collapse to a checkbox again:

Open questions

It is unclear what we do with methods like org.apache.jmeter.testelement.TestPlan#setSerialized(boolean) and boolean org.apache.jmeter.testelement.TestPlan#isSerialized().

We might add a second pair of getter and setter for exposing the property as String, so the UI element can propagate the free-form text expression to the test plan configuration.

I remember I had the same issue with OpenModelThreadGroup where I created two properties randomSeed: Long and randomSeedString: String:

jmeter/src/core/src/main/kotlin/org/apache/jmeter/threads/openmodel/OpenModelThreadGroup.kt

Lines 91 to 100 in 4d9d99a

	public val randomSeed: Long get() = getPropertyAsLong(RANDOM_SEED)
	/**
	* Random seed for building reproducible schedules. 0 means random seed.
	*/
	public var randomSeedString: String
	get() = getPropertyAsString(RANDOM_SEED)
	set(value) {
	setProperty(RANDOM_SEED, value)
	}

Duplicating properties does not look nice :-(

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly.

[vdaburon]

Yes interresting feature. Be carreful with compatibility with current Jmeter script.

[vlsi]

I've added property descriptors, and the missing bit is to link "editable combobox" with BooleanPropertyDescriptor somehow

[vlsi]

I got TestPlan working with editable checkboxes.

Output xml:

<?xml version="1.0" encoding="UTF-8"?>
<jmeterTestPlan version="1.2" properties="5.0" jmeter="5.5.1-SNAPSHOT b17bbbe">
  <hashTree>
    <TestPlan guiclass="TestPlanGui" testclass="TestPlan" testname="Test Plan" enabled="true">
      <stringProp name="TestPlan.comments"></stringProp>
      <stringProp name="TestPlan.functional_mode">asdfasdf</stringProp>
      <stringProp name="TestPlan.serialize_threadgroups">${__P(property_name)}</stringProp>
      <elementProp name="TestPlan.user_defined_variables" elementType="Arguments" guiclass="ArgumentsPanel" testclass="Arguments" testname="User Defined Variables" enabled="true">
        <collectionProp name="Arguments.arguments"/>
      </elementProp>
      <stringProp name="TestPlan.user_define_classpath"></stringProp>
      <stringProp name="TestPlan.tearDown_on_shutdown">${variable_name}</stringProp>
    </TestPlan>
    <hashTree/>
  </hashTree>
</jmeterTestPlan>

[vlsi]

I rearranged the commits, and will split them into different PRs soon.

For reference, here are the changes to migrate TestPlan to editable checkboxes: 3943b08

-    private final JCheckBox serializedMode;
+    private final JBooleanPropertyEditor serializedMode =
+            new JBooleanPropertyEditor(TestPlanSchema.INSTANCE.getSerializeThreadgroups(), "testplan.serialized");

-            tp.setSerialized(serializedMode.isSelected());
+            serializedMode.updateElement(tp);

-            serializedMode.setSelected(tp.isSerialized());
+            serializedMode.updateUi(tp);

-        serializedMode.setSelected(false);
+        serializedMode.reset();

It looks good to me.

[vlsi]

Frankly speaking, getPropertyOrNull followed by instanceof NullProperty look strange, however, I do not change it in the current PR.
However, it would probably make sense to revise it later.

[vlsi]

I'm happy with the code and behaviour, so I will merge this soon

[milamberspace]

Perhaps need add refresh the UI when it's switch the checkbox to expression field (and return). See video.

simplescreenrecorder-2023-06-07_09.39.21.mp4

[vlsi]

Good catch. It updates automatically in Darklaf themes, and almost all the others fail to update.

[vlsi]

I've added relayout in f4d312c

[vdaburon]

Hi,
I think this new features (right click : context menu and select box) are not described in the Test Plan help documentation
https://jmeter.apache.org/usermanual/component_reference.html#Test_Plan
and
Http Sampler documentation
https://jmeter.apache.org/usermanual/component_reference.html#HTTP_Request

Regards.