EINDHOVEN JAVA MEETUP18 May 2016

that spin your world!

AGENDA

¢ 17:30 Welcome with diner¢ 18:00 Application development with

Dynamo¢ 19:10 Break¢ 19:20 Apache Spark¢ 20:20 Q&A¢ 21:00 Closing doors

APPLICATION DEVELOPMENTWITH THE DYNAMO FRAMEWORKEindhoven, 18th of May 2016

that spin your world!

SPEAKER INTRODUCTION

¢ Patrick Deenen� R&D Director @ Open Circle Solutions

¢ Roles� Software Architect� Consultant� Software Engineer

¢ Experience� 25 years experience with custom application development� Mostly administrative systems� Background in 4GL (before 1998)� and web technology (since 1998, Java)� Focused on productivity, custom apps and architecture

JAVA SOFTWARE DEVELOPMENT

• Mature language• Backwards compatible• Large number of available libraries

• But….• Development of new features goes rather slowly• Lacks some of the cooler features of new languages• Rather verbose• Standard Java web framework (JSF) is impopular

(DE FACTO) STANDARDS

¢ JPA (Hibernate/EclipseLink) is widely used for ORM¢ Several mature and viable application frameworks are

available:� Java EE 7� Spring� Blueprint

¢ Many different user interface technologies: JSP, JSF, Wicket, Tiles, Tapestry

JAVASCRIPT AND RESTFUL SERVICES

¢ JavaScript and HTML(5) have come a long way (e.g. AngularJS)

¢ Representational State Transfer (REST) services offer aneasy way of communicating with a Java backend

¢ Well suited for consumer websites¢ Less suitable (we think) for complex business applications

PRODUCTIVITY

• Java EE and many libraries typically provide a fairly low level of abstraction

• Java is a verbose language that lacks many advancedfeatures found in more modern languages

• Naive approach leads to lots of boilerplate, code duplication, and busywork

• Java 8 adds some very welcome improvements (but is itenough?)

PRODUCTIVITY (2)

• Use (Open Source) libraries and products to increaseproductivity

• Use code generators to generate the scaffolding/boilerplate• Use fourth-generation languages (4GL)• Develop your own framework to increase abstraction level:

• Convention over configuration• Declarative programming• Don’t repeat yourself (DRY)

INTRODUCING

• Open Source pure Java framework based on proven productive technologies

• Leverages power of JPA 2 and Spring Framework• Offers base classes for Data Access layer and Service layer• Uses Vaadin for building rich user interfaces• Uses an adaptable metadata model called the Entity Model

as the basis for powerful composite user interface components

SUPPORTED USE CASES BY DYNAMO

• Search structured information (variable number of entities)• User can enter filter criteria• Results can be displayed and sorted

• Display specific information (exactly one entity)• After user selection in search result• After user selection of static hyper link• Supports master-detail

• Create, update and delete information (one or more entities)• Validate information before commit• Supports master-detail

• Most in several different presentation structures

DYNAMO TECHNOLOGIES: JPA

• JPA 2.1 is the Java standard for ORM• Hibernate implementation• Powerful model with fairly high degree of abstraction• Convention over configuration, smart use of annotations

DYNAMO TECHNOLOGIES: SPRING

• Spring 4.x is an application framework that we use to tie together the various parts of a Dynamo application

• XML-based and annotation-based configuration• Dependency injection, transaction support, Apache Camel

integration, aspect-oriented programming (AOP)• Lots and lots of utilities and convenience classes

DYNAMO TECHNOLOGIES: VAADIN

• Rich Java user interface library (dialogs, trees, dragand drop, server push etc.) for building single page applications

• Component- and event driven (similar to Swing/Wicket)• Write almost exclusively in Java• Java code runs on the server but automatically

synchronizes with a Javascript client (100% ajax)• Browser-independent without the need to know any

Javascript

VAADIN ARCHITECTURE

DYNAMO TECHNOLOGIES: VAADIN (3)• Extensive component library• Easy styling due to built-in themes• Many add-ons an plugins available in the Vaadin

Marketplace• Support for multiple sessions in separate browser

windows

CONCEPT: ENTITY MODEL

• The Entity Model describes how the user can search for or create/edit an Entity

• Based primarily on the metadata of the object:• Type of a property determines the type of the field (e.g text field,

combo box) that is used to edit the property• @NotNull annotation requires if a field is required• @Temporal determines if you get a date picker, a date picker with

time, or a time field• Etc..

• Convention over configuration• Default behaviour (of both entity and its properties) can be

modified by the programmer

CONCEPT: ENTITY MODEL (2)@Entity@Table(name = "meetings")

@AttributeOrder(attributeNames = { "description", "desiredLocation", "meetingDate", "startTime",

"endTime", "attendees", "whiteboard", "videoConferencing", "phoneConferencing", "priority" })@Model(displayProperty = "description")

public class Meeting extends AbstractEntity<Integer> {

• Any JPA entity can be used in the Entity Model• @Model and @AttributeOrder can be used to override

default behaviour

CONCEPT: ENTITY MODEL (3)• The Entity Model is constructed by the Entity Model

Factory singleton• Entity Models are constructed lazily when first requested,

and are effectively immutable singletons

public interface EntityModelFactory {<T> EntityModel<T> getModel(Class<T> entityClass);<T> EntityModel<T> getModel(String reference,

Class<T> entityClass);

ATTRIBUTE SETTINGS

• More than 25 settings are supported• Where does the property show up: in search form, in table,

in edit form• Editable versus read-only• Description, tooltip, prompt, default value• Formatting: decimal precision, percentage signs, date

formatting, custom boolean formatting (Yes/No, On/Off)• Validation: required, min/max length, e-mail check• What edit component to use: text field versus text area,

combobox versus lookup field versus list box.• Control over searching (case sensitivity, substring

matching)

ATTRIBUTE DEFINITIONS@Size(max = 200)@Attribute(searchable = true)private String description;

@Column(name = "meeting_date")private Date meetingDate;

private Boolean videoConferencing = Boolean.FALSE;

EXAMPLE: CHANGE COMPONENT TYPE• selectMode = AttributeSelectMode.LIST

• selectMode = AttributeSelectMode.COMBO

• selectMode = AttributeSelectMode.LOOKUP

MESSAGE BUNDLE OVERWRITES

• Message bundle entries can be used to provide localizationor to overwrite behaviour in special cases

SimulationProgramme.code.readOnly=trueSimulationProgramme.simulationMode.readOnly=trueSimulationProgramme.simulationMode.visible=trueSimulationProgramme.simulationDescription.visible=trueSimulationProgramme.salesOrganisation.readOnly=true

COMPOSITE USER INTERFACECOMPONENTS

• Dynamo can generate search or edit screens based on the Entity Model and a single high level UI component.

• In a typical scenario, a couple of lines of code are enough todefine an entire screen

• Behaviour of the screen can be further customised usingparameters and callback methods• Custom components• Default filters• Filters to be applied to lookup components (combo boxes, popup

search screens)• Change listeners/interfield dependencies• Extra custom buttons

EXAMPLE: SIMPLESEARCHLAYOUT

• Search screen, consisting of search form and results table• Search field is generated automatically for every property

that is defined as “searchable”.• Includes pop-up search fields, three-way booleans, range fields

for dates/numbers• Correct filters are automatically applied when the

“Search” button is clicked

EXAMPLE: SIMPLESEARCHLAYOUT (2)• Component supports editing/adding of entities by

switching to separate detail screen• Parameters can be used to toggle addition/editing/deletion

functionality• Detail screen can be opened in edit mode or read-only

mode.

EXAMPLE: SIMPLESEARCHLAYOUT (3)

FormOptions fo = new FormOptions();

fo.setShowRemoveButton(true);

SimpleSearchLayout<Integer, Meeting> searchLayout = new SimpleSearchLayout<>(meetingService, getModelFactory().getModel(Meeting.class), QueryType.ID_BASED, fo,new SortOrder("description", SortDirection.ASCENDING));mainLayout.addComponent(searchLayout);

EXAMPLE: SPLITLAYOUT

• Screen consisting of a table (with limited search options) and an accompanying edit form

• Table can be displayed either above (VERTICAL) or to the left (HORIZONTAL) of the edit form

• Selecting an item in the table automatically loads the item in the edit view

• Standard buttons for adding, removing• Edit form can be switched between edit mode, read-only

mode, and custom view

OTHER COMPONENTS

• SimpleEditLayout (edit form for editing a single entity)• TabularEditLayout (table that allows direct editing)• LazyTabLayout (tab panel component that loads the

contents of a tab only when needed)• Upload component with progress bar support• Data grid with pivot functionality• Generic functionality for exporting table content to Excel• Multi-level lazy editable tree table• MenuService for declaratively creating menu based on

message bundles• Declarative role-based security

DATA ACCESS

• Components use Vaadin LazyQueryContainer whichprovides lazy loading of data

• Standard paging approach• ID-based querying (driving query pattern) allows efficient

fetching of entity hierarchies

WARNING: NOT A CODE GENERATOR

• Dynamo framework automatically generates screens basedon metadata and declarations

• The metadata and declarations are (of course) defined at design time

• Actual screen generation happens at runtime – no code is generated up front

• Dynamo does provide a Maven archetype for quick project setup

YOUR MILEAGE MAY VARY

• Dynamo is best suited for data entry/administrativeapplications

• Emphasis is on productivity• Not as suitable for end user websites or mostly read-only

systems• Dynamo currently only supports relational databases

(SQL) for storage• Current implementation relies on Spring framework (Java

EE support upcoming)

CHECK OUT GITHUB

• The code of the Dynamo Framework is available in GitHub.• Check out https://github.com/opencirclesolutions/dynamo• Feel free to contribute!

DEMO TIME!¢ Dynamo showcase