Let a data object to be converted from JSON with a factory method ins…

…tead of a constructor. This enables interfaces to be data object and be convertible from JSON in data objects containing them.

In addition we also allow an interface to be annotated both with @VertxGen and @dataobject, this can be useful for avoiding to break backward compatibility.

vertx-codegen-json/src/test/java/io/vertx/test/codegen/converter/AutoMapped.java

@@ -0,0 +1,46 @@
+package io.vertx.test.codegen.converter;
+
+import io.vertx.codegen.annotations.DataObject;
+import io.vertx.core.json.JsonObject;
+
+import java.util.Objects;
+
+@DataObject
+public interface AutoMapped {
+
+  static AutoMapped fromJson(JsonObject json) {
+    int port = json.getInteger("port", -1);
+    String host = json.getString("host");
+    return of(host, port);
+  }
+
+  static AutoMapped of(String host, int port) {
+    return new AutoMapped() {
+      @Override
+      public int port() {
+        return port;
+      }
+      @Override
+      public String host() {
+        return host;
+      }
+      @Override
+      public int hashCode() {
+        return host.hashCode() + port;
+      }
+      @Override
+      public boolean equals(Object obj) {
+        AutoMapped that = (AutoMapped) obj;
+        return Objects.equals(host(), that.host()) && port() == that.port();
+      }
+    };
+  }
+
+  int port();
+
+  String host();
+
+  default JsonObject toJson() {
+    return new JsonObject().put("port", port()).put("host", host());
+  }
+}

vertx-codegen-json/src/test/java/io/vertx/test/codegen/converter/AutoMappedWithVertxGen.java

@@ -0,0 +1,49 @@
+package io.vertx.test.codegen.converter;
+
+import io.vertx.codegen.annotations.DataObject;
+import io.vertx.codegen.annotations.VertxGen;
+import io.vertx.core.json.JsonObject;
+
+import java.util.Objects;
+
+@DataObject
+@VertxGen
+public interface AutoMappedWithVertxGen {
+
+  static AutoMappedWithVertxGen fromJson(JsonObject json) {
+    int port = json.getInteger("port", -1);
+    String host = json.getString("host");
+    return of(host, port);
+  }
+
+  static AutoMappedWithVertxGen of(String host, int port) {
+    return new AutoMappedWithVertxGen() {
+      @Override
+      public int port() {
+        return port;
+      }
+      @Override
+      public String host() {
+        return host;
+      }
+      @Override
+      public int hashCode() {
+        return host.hashCode() + port;
+      }
+      @Override
+      public boolean equals(Object obj) {
+        AutoMappedWithVertxGen that = (AutoMappedWithVertxGen) obj;
+        return Objects.equals(host(), that.host()) && port() == that.port();
+      }
+    };
+  }
+
+
+  int port();
+
+  String host();
+
+  default JsonObject toJson() {
+    return new JsonObject().put("port", port()).put("host", host());
+  }
+}