overview.adoc

Overview

The ESPD application is composed of two Maven modules:

• espd-docs contains the documentation of the application

• espd-web contains the source code to generate the deployable web archive (WAR) of the application

The Java library eu.europa.ec.grow.espd.exchange-model contains the JAXB classes of the ESPD Exchange Data Model.

The ESPD web application is quite simple in nature and can be deployed as an executable JAR file (with an embedded Tomcat server) or as a standard WAR file on a compliant Servlet 3 container like Tomcat, Jetty, Weblogic, Wildfly etc.

The main responsibilities of the application are handled as follows:

• Infrastructural support at the application level and dependency injection via the Spring framework

• Configuration of the application via Spring Boot

• Logging with the SLF4J API and Logback as implementation

• The view part uses Spring MVC, JSP files, Apache Tiles, Javascript, jQuery and Twitter Bootstrap

• The data model uses JAXB to convert Java objects to XML and vice versa

• REST calls to external services are handled with the Spring Rest Template client

• Monitoring and analytics via Java Melody and Piwik

• Optimization of static resources with Spring asset pipeline and WRO4J

Java packages overview

The main Java package of the web application is 'eu.europa.ec.grow.espd` found in the espd-web module. It is further subdivided into the following important packages:

• config

• controller

• domain

• ted

• util

• xml

Config package

The config package contains the Java classes which provide the configuration for the global project EspdApplication, Spring MVC web configuration WebConfiguration, the JAXB configuration etc. You will notice that these classes are annotated with @Configuration and they generally define Spring beans that can be injected in other Spring managed classes of the application.

Controller package

The controller package consists of the Spring MVC controllers which are responsible for processing user requests, building an appropriate model and passing it to the view for rendering. Some controllers are REST controllers.

The most important one is EspdController and its responsibilities include dealing with the generation of the ESPD requests and responses, uploading files, printing and error handling. The main flow of the application is handled by this class.

Other controllers which are present in this package are the AboutController that is used to populate the /about page of the application and MessageSourceController which is responsible for loading the i18n messages needed by the client-side i18n engine.

Domain package

The domain package contains the elements involved in the representation of an ESPD request or response in the model (the M part of the MVC architectural pattern) of the web application. An ESPD request/response is represented internally as an EspdDocument which in turn contains fields for all the possible criteria, authority and economic operator information or procurement procedure data.

In the domain.enums sub-package you can find the enumerations holding the criteria, requirement groups, requirements, countries, languages, currencies etc which are used by the application. The criteria definitions load metadata coming from some JSON configuration files under src/main/resources/criteria and store the information dynamically in the criterion enumerations.

TED package

The ted package is responsible for the interaction with the TED REST service which provides the procurement procedure information for an ESPD request or response.

Note	TED is the electronic version of the EU Official Journal dedicated to public procurement.

Util package

The util package contains various utility classes, for example, some of the application properties that are needed by the user interface are loaded by Spring in the EspdConfiguration class. The I18NFunc class loads the i18n messages needed by the client-side internationalization engine.

XML package

The xml package takes care of the marshalling/unmarshalling of the ESPD request and response XML files. It is further divided into a package for request, one for response and a common package with shared functionality between the other two. The classes from this package make use of the Template method design pattern to share common behaviour and design.

The request and response packages contain each an exporting and an importing sub-package. The exporting package is responsible for generating the ESPD request/response XML files while the importing package knows how to parse XML files representing ESPD request or response and convert them into the internal ESPD domain objects.

The EspdExchangeMarshaller is the main class that aggregates all of the classes from this package together and is injected in the EspdController to perform the marshalling/unmarshalling logic.

CriteriaTemplates serves as configuration for the user interface components of the criteria and requirements that are defined in the JSP and Apache Tiles files.

Web overview

The web static resources can be found in the standard Maven location, i.e. src/main/webapp. The static folder contains the CSS and Javascript files referenced by the web application. The JSP files are located in the WEB-INF/views folder where they are subsequently grouped in sub-folders. The src/main/resources folder contains the configuration files relating to internationalization, logging, web resource optimizations and general application properties.