Permit Callback.pathItemRef to be any JSON path

core/src/main/java/io/smallrye/openapi/runtime/io/callbacks/CallbackIO.java

@@ -32,7 +32,7 @@ public Callback read(AnnotationInstance annotation) {
         callback.setRef(ReferenceType.CALLBACK.refValue(annotation));
 
         Optional.ofNullable(this.<String> value(annotation, PROP_PATH_ITEM_REF))
-                .map(ReferenceType.PATH_ITEM::referenceOf)
+                .map(ReferenceType.PATH_ITEM::parseRefValue)
                 .ifPresent(ref -> callback.addPathItem(
                         value(annotation, PROP_CALLBACK_URL_EXPRESSION),
                         OASFactory.createPathItem().ref(ref)));

extension-jaxrs/src/test/java/io/smallrye/openapi/runtime/scanner/CallbackScanTests.java

@@ -9,6 +9,8 @@
 import org.eclipse.microprofile.openapi.OASConfig;
 import org.eclipse.microprofile.openapi.annotations.Components;
 import org.eclipse.microprofile.openapi.annotations.OpenAPIDefinition;
+import org.eclipse.microprofile.openapi.annotations.PathItem;
+import org.eclipse.microprofile.openapi.annotations.PathItemOperation;
 import org.eclipse.microprofile.openapi.annotations.callbacks.Callback;
 import org.eclipse.microprofile.openapi.annotations.callbacks.CallbackOperation;
 import org.eclipse.microprofile.openapi.annotations.info.Info;
@@ -47,4 +49,30 @@ public String hello() {
         printToConsole(result);
         assertJsonEquals("callback.reference-component-callback.json", result);
     }
+
+    @Test
+    void testCallbackPathItemReference() throws Exception {
+        @OpenAPIDefinition(info = @Info(title = "Greetings", version = "0.0.1"), components = @Components(pathItems = @PathItem(name = "myPathItem", operations = @PathItemOperation(method = "POST", responses = {
+                @APIResponse(responseCode = "2XX", description = "Ok"),
+                @APIResponse(responseCode = "5XX", description = "Failed"),
+        }))))
+        class App extends Application {
+        }
+
+        @Path("/")
+        class Resource {
+            @GET
+            @Produces(MediaType.TEXT_PLAIN)
+            @Callback(name = "cb1", callbackUrlExpression = "/test1", pathItemRef = "myPathItem")
+            @Callback(name = "cb2", callbackUrlExpression = "/test2", pathItemRef = "#/components/pathItems/myPathItem")
+            public String hello() {
+                return "goodbye";
+            }
+        }
+
+        Index index = indexOf(App.class, Resource.class);
+        OpenAPI result = OpenApiProcessor.bootstrap(dynamicConfig(OASConfig.FILTER, UnusedSchemaFilter.class.getName()), index);
+        printToConsole(result);
+        assertJsonEquals("callback.reference-component-pathitem.json", result);
+    }
 }

extension-jaxrs/src/test/resources/io/smallrye/openapi/runtime/scanner/callback.reference-component-pathitem.json

@@ -0,0 +1,53 @@
+{
+  "openapi" : "3.1.0",
+  "info" : {
+    "title" : "Greetings",
+    "version" : "0.0.1"
+  },
+  "components" : {
+    "pathItems" : {
+      "myPathItem" : {
+        "post" : {
+          "responses" : {
+            "2XX" : {
+              "description" : "Ok"
+            },
+            "5XX" : {
+              "description" : "Failed"
+            }
+          }
+        }
+      }
+    }
+  },
+  "paths" : {
+    "/" : {
+      "get" : {
+        "responses" : {
+          "200" : {
+            "description" : "OK",
+            "content" : {
+              "text/plain" : {
+                "schema" : {
+                  "type" : "string"
+                }
+              }
+            }
+          }
+        },
+        "callbacks" : {
+          "cb1" : {
+            "/test1" : {
+              "$ref" : "#/components/pathItems/myPathItem"
+            }
+          },
+          "cb2" : {
+            "/test2" : {
+              "$ref" : "#/components/pathItems/myPathItem"
+            }
+          }
+        }
+      }
+    }
+  }
+}

model/src/main/java/io/smallrye/openapi/model/ReferenceType.java

@@ -83,15 +83,13 @@ public String referenceOf(String ref) {
     }
 
     /**
-     * Reads a string property named "ref" value from the given annotation and converts it
-     * to a value appropriate for setting on a model's "$ref" property.
+     * Takes the value from a ref property from an annotation, and converts it to a JSON Pointer, suitable for use as a
+     * reference in an OpenAPI model.
      *
-     * @param annotation AnnotationInstance
-     * @return String value
+     * @param ref the ref value read from an annotation
+     * @return a value suitable for use in an OpenAPI model.
      */
-    public String refValue(AnnotationInstance annotation) {
-        String ref = referenceValue(annotation);
-
+    public String parseRefValue(String ref) {
         if (ref == null) {
             return null;
         }
@@ -102,4 +100,16 @@ public String refValue(AnnotationInstance annotation) {
 
         return referenceOf(ref);
     }
+
+    /**
+     * Reads a string property named "ref" value from the given annotation and converts it
+     * to a value appropriate for setting on a model's "$ref" property.
+     *
+     * @param annotation AnnotationInstance
+     * @return String value
+     */
+    public String refValue(AnnotationInstance annotation) {
+        String ref = referenceValue(annotation);
+        return parseRefValue(ref);
+    }
 }