reader listener support

Author: frantuma

modules/swagger-jaxrs2/src/main/java/io/swagger/jaxrs2/Reader.java

@@ -132,10 +132,37 @@ public int compare(Class<?> class1, Class<?> class2) {
         });
         sortedClasses.addAll(classes);
 
+        Map<Class<?>, ReaderListener> listeners = new HashMap<>();
+
+        for (Class<?> cls : sortedClasses) {
+            if (ReaderListener.class.isAssignableFrom(cls) && !listeners.containsKey(cls)) {
+                try {
+                    listeners.put(cls, (ReaderListener) cls.newInstance());
+                } catch (Exception e) {
+                    LOGGER.error("Failed to create ReaderListener", e);
+                }
+            }
+        }
+
+        for (ReaderListener listener : listeners.values()) {
+            try {
+                listener.beforeScan(this, openAPI);
+            } catch (Exception e) {
+                LOGGER.error("Unexpected error invoking beforeScan listener [" + listener.getClass().getName() + "]", e);
+            }
+        }
+
         for (Class<?> cls : sortedClasses) {
             read(cls, "");
         }
 
+        for (ReaderListener listener : listeners.values()) {
+            try {
+                listener.afterScan(this, openAPI);
+            } catch (Exception e) {
+                LOGGER.error("Unexpected error invoking afterScan listener [" + listener.getClass().getName() + "]", e);
+            }
+        }
         return openAPI;
     }
 

modules/swagger-jaxrs2/src/main/java/io/swagger/jaxrs2/ReaderListener.java

@@ -0,0 +1,33 @@
+package io.swagger.jaxrs2;
+
+import io.swagger.oas.models.OpenAPI;
+
+/**
+ * Listener providing hooks for customizing automatically generated OpenAPI definitions in a JAX-RS
+ * environment. Any classes picked up during the scanning process implementing this interface will
+ * be instantiated via newInstance() and invoked before and after generating OpenAPI definitions, allowing
+ * code to add additional data or change the generated definition.
+ */
+
+public interface ReaderListener {
+
+    /**
+     * Called before the OpenAPI definition gets populated from scanned classes. Use this method to
+     * pre-process the OpenAPI definition before it gets populated.
+     *
+     * @param reader  the reader used to read annotations and build the openAPI definition
+     * @param openAPI the initial OpenAPI definition
+     */
+
+    void beforeScan(Reader reader, OpenAPI openAPI);
+
+    /**
+     * Called after a OpenAPI definition has been populated from scanned classes. Use this method to
+     * post-process OpenAPI definitions.
+     *
+     * @param reader  the reader used to read annotations and build the OpenAPI definition
+     * @param openAPI the configured OpenAPI definition
+     */
+
+    void afterScan(Reader reader, OpenAPI openAPI);
+}

modules/swagger-jaxrs2/src/test/java/io/swagger/jaxrs2/annotations/readerListener/ReaderListenerTest.java

@@ -0,0 +1,24 @@
+package io.swagger.jaxrs2.annotations.readerListener;
+
+import io.swagger.jaxrs2.Reader;
+import io.swagger.jaxrs2.resources.ReaderListenerResource;
+import io.swagger.oas.models.OpenAPI;
+import org.testng.annotations.Test;
+
+import java.util.Collections;
+
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertNotNull;
+
+public class ReaderListenerTest {
+
+    @Test(description = "test a readerListener resource")
+    public void testReaderListener() throws Exception{
+        Reader reader = new Reader(new OpenAPI());
+        OpenAPI openAPI = reader.read(Collections.singleton(ReaderListenerResource.class));
+        assertNotNull(openAPI);
+        assertEquals(openAPI.getTags().get(0).getName(), "Tag-added-before-read");
+        assertEquals(openAPI.getTags().get(1).getName(), "Tag-added-after-read");
+    }
+
+}

modules/swagger-jaxrs2/src/test/java/io/swagger/jaxrs2/resources/ReaderListenerResource.java

@@ -0,0 +1,45 @@
+package io.swagger.jaxrs2.resources;
+
+import io.swagger.jaxrs2.Reader;
+import io.swagger.jaxrs2.ReaderListener;
+import io.swagger.oas.annotations.Operation;
+import io.swagger.oas.annotations.Parameter;
+import io.swagger.oas.annotations.media.Schema;
+import io.swagger.oas.models.OpenAPI;
+import io.swagger.oas.models.tags.Tag;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Response;
+
+public class ReaderListenerResource implements ReaderListener {
+
+	@GET
+	@Path("/")
+	@Operation(operationId = "operationId",
+			summary = "Operation Summary",
+			description = "Operation Description")
+	public Response getSummaryAndDescription(@QueryParam("subscriptionId") @Parameter(in = "path", name = "subscriptionId",
+			required = true, description = "parameter description",
+			allowEmptyValue = true, allowReserved = true,
+			schema = @Schema(
+					type = "string",
+					format = "uuid",
+					description = "the generated UUID",
+					readOnly = true)
+	) String subscriptionId,
+											 @QueryParam("description") String description) {
+		return Response.ok().entity("ok").build();
+	}
+
+	@Override
+	public void beforeScan(Reader reader, OpenAPI openAPI) {
+		openAPI.addTagsItem(new Tag().name("Tag-added-before-read"));
+	}
+
+	@Override
+	public void afterScan(Reader reader, OpenAPI openAPI) {
+		openAPI.addTagsItem(new Tag().name("Tag-added-after-read"));
+	}
+}