SONARJAVA-5294 Create rule S7185: @eventlistener methods should have …

…one parameter (#4618)

rules/S7185/java/metadata.json

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+{
+  "title": "@EventListener methods should have one parameter at most",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "spring"
+  ],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-7185",
+  "sqKey": "S7185",
+  "scope": "All",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "RELIABILITY": "HIGH"
+    },
+    "attribute": "LOGICAL"
+  }
+}

rules/S7185/java/rule.adoc

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+== Why is this an issue?
+
+Spring provides the `@EventListener` annotation as a simpler alternative to implementing the `ApplicationListener` interface for handling events. The `@EventListener` annotation registers a method as an event handler.
+This allows to skip the implementation of the `ApplicationListener` interface, making it easier to handle events.
+
+The `@EventListener` annotation can only be used on methods that have at most one parameter, which should be the specific event that we want to handle.
+To listen to several types of events, use the `classes` argument of the `@EventListener` annotation.
+
+This rule raises an issue on all methods annotated with `@EventListener` that have more than one parameter.
+
+== How to fix it
+
+=== Code examples
+
+==== Noncompliant code example
+
+[source,java,diff-id=1,diff-type=noncompliant]
+----
+@EventListener
+void handleEvent(CustomerEvent customerEvent, ExceptionalEvent exceptionalEvent) { // Non compliant, this will cause a runtime error
+    //... some event handling
+}
+----
+
+==== Compliant solution
+
+[source,java,diff-id=1,diff-type=compliant]
+----
+@EventListener(classes = {CustomerEvent.class, ExceptionalEvent.class})
+void handleEvent(ApplicationEvent event) { // Only one parameter, of the super type `ApplicationEvent`
+    //... some event handling
+}
+----
+
+== Resources
+=== Documentation
+
+Spring API - https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/context/event/EventListener.html[@EventListener]

rules/S7185/metadata.json

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+{
+}