How to create a cucumber-java custom formatter to get cucumber tags - cucumber-jvm

Question

I have a cucumber project and I want to get al the tags in the project to be able to choose them as parameters.
I found this question where cucumber had an option to get the tags but I found that doesn't work anymore, then I found this other question where I found I need a custom formatter to get my tags, but it is for ruby, and I need it for Java, so then I found this article on how to create a custom formatter, but I found that this worked for the cukes version and I'm using the io one.
So I searched inside the cucumber packages and created a custom formatter from a copy of the JSONFormatter inside the package cucumber.runtime.formatter, here is my code:
import cucumber.api.TestCase;
import cucumber.api.event.*;
import cucumber.api.formatter.Formatter;
import cucumber.api.formatter.NiceAppendable;
import gherkin.deps.com.google.gson.Gson;
import gherkin.deps.com.google.gson.GsonBuilder;
import gherkin.pickles.PickleTag;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
public class TagsFormatter implements Formatter {
private String currentFeatureFile;
private final Gson gson = new GsonBuilder().setPrettyPrinting().create();
private final NiceAppendable out;
private List<String> tags = new ArrayList<>();
private EventHandler<TestCaseStarted> caseStartedHandler = this::handleTestCaseStarted;
private EventHandler<TestRunFinished> runFinishedHandler = event -> finishReport();
public TagsFormatter(Appendable out) {
this.out = new NiceAppendable(out);
}
#Override
public void setEventPublisher(EventPublisher publisher) {
publisher.registerHandlerFor(TestCaseStarted.class, caseStartedHandler);
publisher.registerHandlerFor(TestRunFinished.class, runFinishedHandler);
}
private void handleTestCaseStarted(TestCaseStarted event) {
if (currentFeatureFile == null || !currentFeatureFile.equals(event.testCase.getUri())) {
currentFeatureFile = event.testCase.getUri();
collectTags(event.testCase);
}
}
private void finishReport() {
out.append(gson.toJson(tags));
out.close();
}
private void collectTags(TestCase testCase) {
testCase.getTags();
tags.addAll(testCase.getTags()
.stream()
.map(PickleTag::getName)
.collect(Collectors.toList()));
}
}
I copied the libraries I need to run cucumber in a lib folder inside my project and tried running it using my formatter like this:
java -cp .\lib\cucumber-core-2.4.0.jar;.\lib\gherkin-5.0.0.jar;.\lib\cucumber-java-2.4.0.jar;.\lib\cucumber-jvm-deps-1.0.6.jar cucumber.api.cli.Main -p "com.myproject.formatters.TagsFormatter:tags.txt"
But Im getting a class not found exception:
λ java -cp .\lib\cucumber-core-2.4.0.jar;.\lib\gherkin-5.0.0.jar;.\lib\cucumber-java-2.4.0.jar;.\lib\cucumber-jvm-deps-1.0.6.jar cucumber.api.cli.Main -p "com.myproject.formatters.TagsFormatter:tags.txt"
Exception in thread "main" cucumber.runtime.CucumberException: Couldn't load plugin class: com.myproject.formatters.TagsFormatter
at cucumber.runtime.formatter.PluginFactory.loadClass(PluginFactory.java:181)
at cucumber.runtime.formatter.PluginFactory.pluginClass(PluginFactory.java:166)
at cucumber.runtime.formatter.PluginFactory.getPluginClass(PluginFactory.java:223)
at cucumber.runtime.formatter.PluginFactory.isFormatterName(PluginFactory.java:201)
at cucumber.runtime.RuntimeOptions$ParsedPluginData.addPluginName(RuntimeOptions.java:471)
at cucumber.runtime.RuntimeOptions.parse(RuntimeOptions.java:157)
at cucumber.runtime.RuntimeOptions.<init>(RuntimeOptions.java:115)
at cucumber.runtime.RuntimeOptions.<init>(RuntimeOptions.java:108)
at cucumber.runtime.RuntimeOptions.<init>(RuntimeOptions.java:100)
at cucumber.api.cli.Main.run(Main.java:31)
at cucumber.api.cli.Main.main(Main.java:18)
Caused by: java.lang.ClassNotFoundException: com.myproject.formatters.TagsFormatter
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at cucumber.runtime.formatter.PluginFactory.loadClass(PluginFactory.java:174)
... 10 more
So, how can I create this formatter in a way it is recognized? or at least get the tags list from cucumber from console?
Thanks

Answer 1

By just eyeballing your code, I don't think there is anything wrong with it. However your command does not appear to include a compiled version of the TagsFormatter on the class path.
If your compiled sources are in .\bin\ make sure to include that folder ie:
java -cp .\lib\cucumber-core-2.4.0.jar;.\lib\gherkin-5.0.0.jar;.\lib\cucumber-java-2.4.0.jar;.\lib\cucumber-jvm-deps-1.0.6.jar;.\bin\* cucumber.api.cli.Main -p "com.myproject.formatters.TagsFormatter:tags.txt"