[wip] initial commit

extracted useful snippets from other projects

src/de/pzzz/vertx/RestDataAccess.java

@@ -0,0 +1,154 @@
+package de.pzzz.vertx;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+
+import io.vertx.core.Vertx;
+import io.vertx.core.eventbus.Message;
+import io.vertx.core.eventbus.MessageConsumer;
+import io.vertx.core.json.Json;
+import io.vertx.ext.web.Router;
+import io.vertx.ext.web.RoutingContext;
+
+public class RestDataAccess<T extends SerializableWithId> {
+    private Map<String, T> dataMap = new HashMap<>();
+    protected final Class<T> classReference;
+
+    public RestDataAccess(final Class<T> classReference) {
+        this.classReference = classReference;
+    }
+
+    public void registerRoutes(final Router router, final String baseUrl) {
+		router.get(baseUrl).handler(this::list);
+        router.post(baseUrl).handler(this::add);
+        router.get(baseUrl + "/:id").handler(this::get);
+        router.put(baseUrl + "/:id").handler(this::update);
+        router.delete(baseUrl + "/:id").handler(this::delete);
+    }
+
+    /**
+     * Returns bus address.
+     *
+     * @param vertx
+     * @return
+     */
+	public String setupConsumer(final Vertx vertx) {
+        final String busAddress = this.getClass().getName() + "." + UUID.randomUUID();
+		MessageConsumer<RestDataRequest<T>> consumer = vertx.eventBus()
+				.consumer(busAddress);
+		consumer.handler(this::handleMessage);
+		return busAddress;
+	}
+
+    public Collection<T> list() {
+        return dataMap.values();
+    }
+
+    public T get(final String id) {
+        return dataMap.get(id);
+    }
+
+    public boolean contains(final String id) {
+        return dataMap.containsKey(id);
+    }
+
+    public void add(final T data) {
+        dataMap.put(data.getId(), data);
+    }
+
+    public void update(final T newData) {
+        dataMap.put(newData.getId(), newData);
+    }
+
+    public void delete(final String id) {
+        dataMap.remove(id);
+    }
+
+    protected void update(final String id, final RoutingContext context) {
+        T newData = Json.decodeValue(context.getBody(), classReference);
+        if (!newData.getId().equals(id)) {
+            context.fail(400);
+        }
+        update(newData);
+    }
+
+    protected T getDataFromRequest(final RoutingContext context) {
+    	return Json.decodeValue(context.getBody(), classReference);
+    }
+
+    private void handleMessage(final Message<RestDataRequest<T>> request) {
+        switch (request.body().getCommand()) {
+            case LIST:
+                request.reply(new ArrayList<>(list()));
+                break;
+            case GET:
+                request.reply(get(request.body().getId()));
+            default:
+                request.fail(500, "Unsupported request type");
+                break;
+        }
+    }
+
+    private void list(final RoutingContext context) {
+		if (context.response().ended()) {
+			return;
+		}
+		context.response().end(Json.encodePrettily(list()));
+    }
+
+    private void add(final RoutingContext context) {
+		if (context.response().ended()) {
+			return;
+		}
+        T data = getDataFromRequest(context);
+		if (context.response().ended()) {
+			return;
+		}
+        add(data);
+		context.response().setStatusCode(201).end();
+    }
+
+    private void get(final RoutingContext context) {
+		if (context.response().ended()) {
+			return;
+		}
+        final String id = context.pathParam("id");
+        if (!dataMap.containsKey(id)) {
+            context.fail(404);
+            return;
+        }
+		context.response().end(Json.encodePrettily(get(id)));
+    }
+
+    private void update(final RoutingContext context) {
+		if (context.response().ended()) {
+			return;
+		}
+        final String id = context.pathParam("id");
+        if (!dataMap.containsKey(id)) {
+            context.fail(404);
+            return;
+        }
+        update(id, context);
+		if (context.response().ended()) {
+			return;
+		}
+		context.response().setStatusCode(204).end();
+    }
+
+    private void delete(final RoutingContext context) {
+		if (context.response().ended()) {
+			return;
+		}
+        final String id = context.pathParam("id");
+        if (!dataMap.containsKey(id)) {
+            context.fail(404);
+            return;
+        }
+        delete(id);
+		context.response().setStatusCode(204).end();
+    }
+}