[GitHub] [jmeter] vlsi opened a new issue, #5946: Add API to declare TestElement schemas

["vlsi (via GitHub)" <gi...@apache.org>]

vlsi opened a new issue, #5946:
URL: https://github.com/apache/jmeter/issues/5946

   ### Use case
   
   Currently, JMeter has two approaches for creating test elements:
   * `implements TestBean`
   * `implements TestElement`
   
   `TestBean`-based elements do not mange `JMeterProperty` themselves, and they rely on `Introspector` and `BeanInfo` to manage the properties.
   
   `TestElement`-based elements (e.g. the ones that extend `AbstractTestElement`) have manage their properties on their own.
   There are several issues with that:
   1. The is no clear way to see which properties are "well-known". Sometimes the elements declare something like `public static final String PORT = "HTTPSampler.port"`, however, it is unclear what is the expected property type, the default value is not there, and sometimes the strings are even `private` (see `TestPlan`, `private static final String FUNCTIONAL_MODE = "TestPlan.functional_mode";`)
   2. Currently, the default value should be passed on every property get and set. For instance, see `ResultCollector`, `getPropertyAsBoolean(SUCCESS_ONLY_LOGGING,false)`. In that case, all users of `SUCCESS_ONLY_LOGGING` should pass the same `false` default value.
   3. Test elements often provide getters and setters for primitive values only. For instance, `org.apache.jmeter.testelement.TestPlan#isSerialized() return boolean` and `org.apache.jmeter.testelement.TestPlan#setSerialized(boolean)` accept only `boolean` values, and they do not allow users to configure `FunctionProperty` for `isSerialized` property.
   
   ### Possible solution
   
   Add API so the plugin authors could configure schema for their elements:
   
   ```kotlin
   public interface PropertyDescriptor {
       public val propertyName: String
       public val defaultValue: Any?
   }
   
   public data class BooleanPropertyDescriptor(
       public override val propertyName: String,
       /** Default value, null means there's no default */
       public override val defaultValue: Boolean?
   ): PropertyDescriptor
   
   public data class StringPropertyDescriptor(
       public override val propertyName: String,
       /** Default value, null means there's no default */
       public override val defaultValue: String?
   ): PropertyDescriptor
   ```
   
   ```kotlin
   /** Similar to Java's Object */
   public abstract class JMeterElementClass {
       private val propertyDescriptors: MutableMap<String, PropertyDescriptor> = mutableMapOf()
       protected fun string(name: String): StringPropertyDescriptor =
           StringPropertyDescriptor(name, null).also {
               propertyDescriptors[name] = it
           }
   
       @JvmOverloads
       protected fun boolean(name: String, default: Boolean? = null): BooleanPropertyDescriptor =
           BooleanPropertyDescriptor(name, null).also {
               propertyDescriptors[name] = it
           }
   }
   
   
   public open class AbstractTestElementClass protected constructor(): JMeterElementClass() {
       public companion object {
           @JvmField
           public val INSTANCE: AbstractTestElementClass = AbstractTestElementClass()
       }
       public val name: StringPropertyDescriptor = string("TestElement.name")
       public val comments: StringPropertyDescriptor = string("TestElement.comments")
       public val guiClass: StringPropertyDescriptor = string("TestElement.gui_class")
       public val testClass: StringPropertyDescriptor = string("TestElement.testClass")
       public val enabled: BooleanPropertyDescriptor = boolean("TestElement.enabled", default = true)
   }
   
   public open class TestPlanClass protected constructor() : AbstractTestElementClass() {
       public companion object {
           @JvmField
           public val INSTANCE: TestPlanClass = TestPlanClass()
       }
       public val isSerialized: BooleanPropertyDescriptor = boolean("isserialized")
   }
   ```
   
   Then users would be able to access the properties like `TestPlanClass.INSTANCE.isSerialized` or `TestPlanClass.INSTANCE.comments`.
   
   `AbstractTestElement` could expose `JMeterElementClass` as well.
   
   For instance:
   
   ```java
   class AbstractTestElement {
       public JMeterElementClass getType() {
           return AbstractTestElementClass.INSTANCE;
       }
   }
   
   ...
   
   class TestPlan extends AbstractTestElement {
       public TestPlanClass getType() {
           return TestPlanClass.INSTANCE;
       }
   }
   ```
   
   Then it would be slightly easier to access the corresponding `JMeterClass`:
   
   ```java
   // kotlin
   val testPlan: TestPlan = ...;
   // type would return TestPlanClass, so IDE would autocomplete the possible property names
   testPlan.type.isSerialized
   ```
   
   ### Possible workarounds
   
   _No response_
   
   ### JMeter Version
   
   5.5
   
   ### Java Version
   
   _No response_
   
   ### OS Version
   
   _No response_


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[GitHub] [jmeter] vlsi commented on issue #5946: Add API to declare TestElement schemas

["vlsi (via GitHub)" <gi...@apache.org>]

vlsi commented on issue #5946:
URL: https://github.com/apache/jmeter/issues/5946#issuecomment-1578168295

   Partially implemented in https://github.com/apache/jmeter/pull/5944


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[GitHub] [jmeter] vlsi commented on issue #5946: Add API to declare TestElement schemas

["vlsi (via GitHub)" <gi...@apache.org>]

vlsi commented on issue #5946:
URL: https://github.com/apache/jmeter/issues/5946#issuecomment-1565639598

   Java does not allow implementing interface with different type parameters: https://bugs.openjdk.org/browse/JDK-8030724
   That means we can't have something like `TestPlan implements DescribedBy<TestPlanClass>` and `TestElement implements DescribedBy<TestElementClass>` at the same time.


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[GitHub] [jmeter] vlsi commented on issue #5946: Add API to declare TestElement schemas

["vlsi (via GitHub)" <gi...@apache.org>]

vlsi commented on issue #5946:
URL: https://github.com/apache/jmeter/issues/5946#issuecomment-1567341770

   I've some progress in https://github.com/apache/jmeter/pull/5944.
   
   Sample usage in Kotlin.
   
   Note: BeanShellSampler has methods like `setScript(String)`, however, it sets plain Java field instead of passing the value to `setProperty(...)`.
   `props[{ script }] =...` sets a corresponding JMeter property.
   
   ```kotlin
   val sampler = BeanShellSampler().apply {
       name = "BeanShell Sampler"
       props[{ script }] = """ResponseMessage="COUNTER=${"$"}{__counter(FALSE)}""""
       props[{ filename }] = ""
       props[{ parameters }] = ""
       TestElementPropertyTransformer.USE_FUNCTIONS.visit(this)
       isRunningVersion = true
   }
   ```
   
   The same in Java:
   
   ```java
   BeanShellSampler sampler = new BeanShellSampler();
   sampler.setName("BeanShell Sampler");
   sampler.getProps().set(BeanShellSamplerClass::getScript, "ResponseMessage=\"COUNTER=${__counter(FALSE)}\"");
   sampler.getProps().set(BeanShellSamplerClass::getFilename, "");
   sampler.getProps().set(BeanShellSamplerClass::getParameters, "");
   TestElementPropertyTransformer.USE_FUNCTIONS.visit(sampler);
   sampler.setRunningVersion(true);
   ```
   
   In the ideal case, `BeanShellSampler` should expose the proper getters and setters on its own (e.g. `setScript(...)` that would propagate to `JMeterProperty`), however, having a common low-level API would be great.
   
   It would be nice to deprecate older "getPropertyAs(String, ..)` as they are unsafe form the `default value` point of view.
   In other words, if a property has a default value, then `getPropertyAs...` should return that default value instead of returning something else.


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[GitHub] [jmeter] vlsi closed issue #5946: Add API to declare TestElement schemas

["vlsi (via GitHub)" <gi...@apache.org>]

vlsi closed issue #5946: Add API to declare TestElement schemas
URL: https://github.com/apache/jmeter/issues/5946


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