Do It The jAPS Way
Copyright © 2010 Tzente s.r.l.
Legal Notice
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the Appendix entitled "GNU Free Documentation License".
2010-03-24
| Revision History | ||
|---|---|---|
| Revision 1.1 | 2010-03-18 | MEM |
|
Revision for the release of jAPS 2.0.10 | ||
| Revision 1.0 | 2009-11-26 | MEM |
|
English translation | ||
Table of Contents
List of Examples
- 4.1. Package Manager Card
- 4.2. name of the Manager Card
- 4.3. Manager Card class
- 4.4. Implementation of the init method
- 4.5. Definition of the name of a manager through a constant
- 4.6. Methods signature
- 4.7. DAO Class
- 4.8. Full definition of the Manager
- 4.9. Extension of the User Manager using the same id of the core service (UserManager)
- 4.10. Create a package for the Action classes for the Card service
- 4.11. Package containing the class Action for Card management
- 4.12. Definition of the action bean
- 4.13. Action definitions in the file card.xml
- 4.14. Example of actions definition in the file PortalExample.xml
- 4.15. jsp of the card manager service
- 4.16. Declaration of the Menu
- 4.17. Redefinition of the "Pages Tree" interface
Table of Contents
The aim of this document is to give a detailed description of the architectural model of jAPS 2.0 and the steps to follow to create a new application service.
This document is for developers aiming to build a new Application Service su jAPS 2.0.
In order to take the maximum advantage of the present document, it is necessary to have a basic knowledge about: the Java platform, the Eclipse IDE, the Apache Tomcat servlet container, the PosgreSQL DBMS and the jAPS 2.0 framework.
Additional informations may be obtained through the following mailing-lists:
<japs-devs@lists.sourceforge.net>, focused on developers<japs-users@lists.sourceforge.net>, focused on final users
Is it also possible to refer to the documentation found in the:
We define the jAPS Manager as a part of the jAPS Core which implements a basic system funtionality. A jAPS Manger is also the main handler of that particular functionality.
The main services belong to one of the following groups:
Basic services:
AuthenticationProviderManager: authenticator service..
BaseConfigManager: configuration service. Load the configuration parameters from system database, making it available to the invoker.
CacheManager: cache handler service.
CategoryManager: category handler service.
ControllerManager: this service supervises the execution of a request coming from the client.
GroupManager: group handler.
I18nManager: this service returns the localized strings upon request
KeyGeneratorManager: this service superintends the generation of primary keys
LangManager: this service handles the various languages of the system
NotifyManager: event notification dispatcher service
PageManager: page handler
PageModelManager: this service handles the various page models
RoleManager: role manager
ShowletTypeManager: this service manages the showlets (ShowletTypes) types defined in the system
UrlManager: this manager creates a URL to page of the Portal from essential informations.
UserManager: account manager
CMS services (served by the jACMS plugin):
ContentManager: contents manager
ContentPageMapperManager: this service manages the map of the contents published in the pages of the portal
LinkResolverManager: this manager resolves the symbolic links
ResourceManager: resources (audio, video, images etc.) handler
SearcheEngineManager: this service creates the indexes of all the objects which will be later parsed by the search engine.
The services defined in the system are initialized during system start-up through the Factory provided by the Spring Framework.
It's important to underline that each service has one and only one instance. The invocation of a service can
be obtained in either two ways: through the "Dependency Injection" technique favored by Spring or using the appropriate
elements of the system like ApsWebApplicationUtils.
Every jAPS manager is described through a specific interface and every object class access a service always
using the appropriate interface, never invoking the class directly.
The manager (o jAPS Manager) is the only linking point between the system data -whatever their origin is- and the functionality which use them.
An example of service is the PageManager which manages the tree of the portal pages. Every operation
involving the pages, such as addition, removal, displaying and so on is handled by the PageManager.
Architectural model of the jAPS 2.0
To fully understand this document it's necessary to describe the architectural model of jAPS: jAPS is mainly composed by 3 layers:
Data Access Layer: It is composed by all the elements which superintend the Persistence Layer. The main component are the DAO classes (Data Access Object) which are the only linking element between the framework and the data sources (Database, Filesystem, LDAP service directory etc.)
Business Layer: This is the core of the system. Here the concept of jAPS service as manager of every macro functionality, takes place. This layer is built upon the Spring Framework, whose listener, during the system start-up, initializes all the services and injects them in the web application context as
beans. The Business Layer utilizes the Data Access layer to get the data needed, gives to the higher layer (the Presentation layer) the elements to display and supports it in the execution of actions.Presentation Layer: The aim of this layer is to build the graphic interfaces which represent the mean through which the users interact with the system. This layer gives a pure View layer (that is, a jsp without any business logic) and a "slim" controller (which checks the consistency of the data submitted and serves the data produced); both of them provide support to the layer below, the Business Layer. In the jAPS framework this layer is divided in two parts: the Portal View (referred as Front-end) and the Administration View (Back-end). These views, which differs by functionality and architecture, are completely independent from each other.
Every application service must be developed in the total respect of the architectural schema above, placing every part in the right layer. The presence of the elements of the new service in all of the three layers depends on characteristics of the service itself. The typical service which needs the usual addition, removal, editing and searching operations will have elements in each layer - take as reference the "Personal Card" management service explained further in this document and found implemented in the "Portal Example" demo. Moreover the "Personal Card" service has customized elements in the "View" layer, both in the Portal and the Administration area. The LDAP plugin, on the contrary, has elements in the Business layer only.
This is the part of the presentation layer where the results of the queries to system services are displayed mainly through the Showlets. Showlets are the preferred method to use to make the system services interact with users. The tasks of the Portal View are to provide services based on the current user permissions (every element of the Portal Layer incorporates the rules which govern the access to services) and to serve content as fast as possible (using content caching mechanism). The portal view is handled by a specialized servlet (ControllerServlet) whose primary target is to invoke a precise succession of services (coherency of the URL, user privilege checks etc) which will finally result in the rendering of the requested page.
This is the area reserved for administration of the various elements of the Portal (Pages, Contents, Resources etc.) whose access is reserved to a restricted pool of users. The view of the Adminstration Area, comprehensive of the controller logic) has been completely redesigned: the reference framework, firmly tied to the Spring framework, is now Struts2. The View has been modified to met the (Italian) Public Administration requisites of accessibility - taking as a firm point the respect of all the W3C standards.
The source files, with the exclusion of the test packages and certain supporting elements (eg. the static resources and the templates directories etc.), are enclosed in two packages:
com.agiletec.aps: here can be found all the elements of the Data Access Layer, Business and presentation Layer (the last limited to the Portal View only)com.agiletec.apsadmin: this package contains all the elements need to manage the presentation layer of the Administration View
A similar division exists in the directory WEB-INF of the web application:
here are contained, including the supporting folders, the usual aps (which contains
all the jsp and the tld files of the Portal View layer) and apsadmin (containing all
the jsp files belonging to the Administration Area).
The following paragraphs explain in detail how to create a new service in the jAPS 2.0 framework.
The main objective of the present document is to allow the jAPS-Developers a fast development of new services to integrate with existing ones, without modifying the Base Core sources (java classes, jsp files, configurations, etc).
During the process of the creation of a new service, the following procedure starts from the implementation of the Business and Data Layer of the new functionality.
Active elements: the classes involved are <NAME_OF_THE_HANDLED_OBJECT>Manager (the name of the service) which must extend the AbstractService class. In a similar manner, if the DAO classes are needed, the <NAME_OF_THE_HANDLED_OBJECT>DAO must extend the AbstractDao class.
Create the package, external to the core classes, respecting the same schema used by the core.
Example 4.1. Package Manager Card
If the new service is called Card, the resulting name
will be it.projectname.aps.system.services.card.
Create an interface, namely Firma del Servizio, which respects the following syntax
I<NAME_OF_THE_HANDLED_OBJECT>Manager.
This interface includes all the public methods (and the costants, if present) of the service which will be
accessible from the outside. Every use of the implemented methods must happen through the invocation of this
interface.
Create the class of the service <NAME_OF_THE_HANDLED_OBJECT>Manager which extends in turn the
AbstractService and implements the methods declared in the interface seen before.
Example 4.3. Manager Card class
public class CardManager extends AbstractService implements ICardManager {
....
}
Take care to implement the init method of the abstract service (which allows the
correct initialization of the service), and the methods declared in the interface properly
Example 4.4. Implementation of the init method
/**
* Service initialization
*/
public void init() throws Exception {
.....
}
Add, in the class (or interface) <PROJECT_NAME>SystemConstants contained in a sub-package aps.system
of the project, the constant <NAME_OF_THE_HANDLED_OBJECT>_MANAGER which uniquely identifies the name of the
service within the project.
Example 4.5. Definition of the name of a manager through a constant
public interface MyProjectSystemConstants {
public static final String CARD_MANAGER = "CardManager";
.......
}
Add the service in a new configuration file, which will be later parsed by Spring. The configuration files
must be inserted in a directory under the /WEB-INF/<PROJECT_NAME>/conf/ following
the same pattern used for the configuration files of the core.
The new Manager must be inserted in the Spring context using a syntax similar to the one shown below:
<bean id="CardManager" class="it.projectname.aps.system.services.card.CardManager" parent="abstractService" > </bean>
where the id is the value of the constant defined previously.
Important
Care must be taken in the definition of the bean since it must not match any other existing ids in the system unless we intend to extend an existing service on purpose.
Make the system aware of the new service by instructing Spring to load every xml file in the configuration
directories of your service. This is typically done editing the /WEB-INF/web.xml and adding
to the xml attribute param-value of the parameter contextConfigLocation the
file pattern string WEB-INF/<PROJECT_NAME>/conf/**/**.xml. This definition must be added in
the last position.
The same pattern must be inserted in method getSpringConfigFilePaths of the class
test.com.agiletec.aps.ConfigUtils. This class is used to setup the proper environment
for the test suites; again, the definition must be placed in the last position.
If the new service uses a DAO (Data Access Object) so that it adds new elements in the Data Layer, the first thing to do is to crate an interface Firma del DAO using this declaration I<NAME_OF_THE_HANDLED_OBJECT>DAO and add, in the class which implements that interface, an instance variable of the same type of the newly created one. This variable must have both getter and setter, with the former being rigorously public.
Example 4.6. Methods signature
public void setCardDao(ICardDAO cardDao); protected ICardDAO getCardDao();
Create the DAO class <NAME_OF_THE_HANDLED_OBJECT>DAO which implements the interface just created.
If we are willing to use a standard JDBC, the class DAO just created must extend the class AbstractDAO.
Inject the new DAO in the bean of the service previously described.
Example 4.8. Full definition of the Manager
<bean id="CardManager" class="it.projectname.aps.system.services.card.CardManager" parent="abstractService" > <property name="cardDao"> <bean class="it.projectname.aps.system.services.card.CardDAO" > <property name="dataSource" ref="dataSourceBeanName" /> </bean> </property> </bean>
NOTE: inject the datasource having care to choose the proper reference between the default "portDataSource" or
"servDataSource" (which always exist in a jAPS installation) and the new data sources eventually created
for the new service.
Every service in the DAO must be tested in its public methods. In other words it's necessary to:
create a java class named <PROJECT_NAME>ConfigUtils (in the package
test.it.projectname) which extends the classConfigUtils; the methods getSpringConfigFilePaths and closeDataSources must be extended as well. The former provides the path for the configuration files of the new service needed by Spring, the latter handles the database connection closure of the new datasources.create a java class <PROJECT_NAME>BaseTestCase (in the package
test.it.projectname.aps) which extends the classtest.com.agiletec.aps.BaseTestCase. Override the method getConfigUtils so that it returns an instance of <PROJECT_NAME>ConfigUtils (that is, the class previously created).Create the test classes Test<NAME_OF_THE_HANDLED_OBJECT>Manager and, if needed, the Test<NAME_OF_THE_HANDLED_OBJECT>DAO in the package
test.it.projectname.aps.system.services.<NAME_OF_THE_HANDLED_OBJECT>Such classes must extend the classes previously created. Remember to test all the public methods of the new service.
To check a service we have obviously to invoke it in every test class; this is done with the following code:
ImyServiceManager myServiceManager = (ImyServiceManager) this.getService(MyProjectSystemConstants.MY_SERVICE_MANAGER);
To test a DAO is necessary to create it as Spring does, passing to it the datasource and as every requested bean.
DataSource dataSource = (DataSource)
this.getApplicationContext().getBean("dataSourceName");
MyServiceDAO myServiceDao = new MyServiceDAO();
myServiceDao.setDataSource(dataSource);
Two databases, namely jAPStestPort and jAPStestServ, are provided for testing purposes. They reflect their "production" counterparts, the jAPSPort and jAPSServ. If the new service requires additional databases they all must have a test and a production version as well.
For every method of the service to test a corresponding method in the appropriate test class must be created:
public void testNomeMetodoDaTestare() {
........
}
When creating test methods it's important to plan the restore of the data in the state they were prior the execution of the test(s), whatever the result is. This assures the coherence and the correctness of the following test. You don't want a failed test to cause a succession of failures in different classes which previously were just fine.
If the newly born service alters existing managers (by either integrating or modifying functionalities)
you are strongly advised to avoid modifying the core! Create inside the package
it.projectname.aps.system.services of your project, a new manager which extends
the existing one. In the Spring configuration file of your service the id of the service must
perfectly match the one of the existing service (of the core of jAPS) that we are going to extend.
Example 4.9. Extension of the User Manager using the same id of the core service (UserManager)
<bean id="UserManager" class="it.projectname.aps.system.services.user.UserManager" parent="abstractService" > <property name="userDAO" > <bean class="it.projectname.aps.system.services.user.UserDAO"> <property name="dataSource" ref="servDataSource" /> </bean> </property> <property name="configManager" ref="BaseConfigManager"/> </bean>
In the previous example, the new bean id UserManager substitutes, having the same name, the
one of the core of jAPS.
Remember to insert all the properties found in the declaration of the core bean in the new one.
The most of the Application services will need an administration interface. In the core of jAPS, the class which superintend the interface mechanism are all grouped inside the package com.agiletec.aspadmin. This package in turn contains other sub packages organized (and separated) by functionality; each serves a well determined function whose controls are displayed in the Administration Area. The new service must present the sources to manage the back-end interfaces developed following the same structure used in the core.
Create the package -outside the Core path!- respecting the schema used in jAPS 2.0, as stated earlier.
Example 4.10. Create a package for the Action classes for the Card service
Suppose to have the need to create Actions to handle the Cards (defined in the homonym class):
the resulting name of the package will be: it.projectname.apsadmin.card.
Crate the java interface Firma delle Action which respectes the syntax I<NAME_OF_THE_HANDLED_OBJECT>Action.
This interface presents all the public methods and eventually the constants, which will be implemented in the
service class. Every method presented in the interface is an action which can be executed.
If our service provides some search function of the object handled by the service we have to create an additional java interface, namely I<NAME_OF_THE_HANDLED_OBJECT>FinderAction. This is the gate to the finder action class.
Create the action class named <NAME_OF_THE_HANDLED_OBJECT>Action which extends the BaseAction and implements the interface above. If needed, create the finder action class which manages the search operations.
Any action class must have a corresponding Spring configuration file; the syntax to use is close to the one shown in the example below.
Example 4.12. Definition of the action bean
<bean id="cardAction" scope=”prototype” class="it.projectname.apsadmin.card.CardAction" parent="abstractBaseAction" > </bean>
Important
The scope of the bean of the action classes must be "prototype" and care must be taken when defining the bean: it must not match any other bean id of the core, unless we are extending an existing service, as we have already seen.
Insert the configuration file in a directory named
/WEB-INF/<PROJECT_NAME>/apsadmin/conf/.
Once again, make spring aware of the new action by adding the followin string WEB-INF/<PROJECT_NAME>/apasadmin/conf/**/**.xml
in the xml attribute param-value of the parameter contextConfigLocation located
in the file /WEB-INF/web.xml. This definition must be placed in the last position.
Create, at the same level of the interfaces and classes, a xml file which contains the definitions of the actions previously implemented. These definitions follow the Struts2 rules; there is one definition for every action which can be triggered by users from the user interface.
Example 4.13. Action definitions in the file card.xml
<struts> <package name="portalExample_do/Card" namespace="/do/Card" extends="japs-default"> <action name="list" class="cardFindingAction"> <result type="tiles">admin.Card.list</result> <interceptor-ref name="japsDefaultStack"> <param name="requestAuth.requiredPermission">superuser</param> </interceptor-ref> </action> ...... <action name="edit" class="cardAction" method="edit"> <result type="tiles">admin.Card.entry</result> <interceptor-ref name="japsDefaultStack"> <param name="requestAuth.requiredPermission">superuser</param> </interceptor-ref> </action> .... </package> </struts>
Note: the name of the Struts2 package must present as prefix the name of the project.
Make use of the stack interceptors defined in the file struts.xml:
japsDefaultStack: this is the default for the actions of the Administration view which need specific permissions to be executed (eg. check for the user permission when accessing the Administration area). This stack does not enforce validation or range check of the submitted parameters. This stack needs the explicit declaration of the permission needed to execute the action in therequiredPermissiontag.japsValidationStack: extension of the japsDefaultStack with the addition of validation checks.japsFreeStack: This stack is to be used for actions both internal and external to the Administration area, which require neither permission nor validation checks.japsFreeValidationStack: Extension of the japsFreeStack stack with validation check enabled.
Create at the same level of the java interface and action classes the appropriate xml files to define the kind and the number of validation checks to perform. These validation files follow the Struts2 syntax for the validation.
Create a new <PROJECT_NAME>-struts.xml in the root of the source files or, in other word, in the same level of the directory where the struts.xml resides. This file must contain all the references to the configuration files of the new actions of the project.
Example 4.14. Example of actions definition in the file PortalExample.xml
<struts> <include file="it/myprojectname/apsadmin/card/card.xml"/> </struts>
The xml file containing the definitions of the various actions of the project must be declared in the
parameter Struts2Config within the /WEB-INF/web.xml file. As always
the definition must be inserted in the last position.
The property files reside in the same directory of the newly created Action classes; theese files provide support for the Internationalization (i18n). These file must follow strictly the rules as specified in documentation released in the Struts2 framework website.
In the properties files must be inserted not only the static labels of the jsp files of the user interfaces,
but all the labels correlated to the validation support.
These labels must be provided for both English and Italian language (the file
package_it.properties and package_en.properties serve this
purpose).
As for the id of the service beans, the keys of the labels must not match any of the common resources keys contained
in the files global-messages_en.properties and global-messages_it.properties.
To avoid problems, you are encouraged to subdivide the label in the following groups:
on menu basis
per titles (h1 e h2)
static strings of the jsp files
string used by the validation files
Create the proper environment and the classes to test new newly created actions. In other words:
create a java class named <PROJECT_NAME>ConfigUtils (or use the class used to test the manager methods) which extends the class
ConfigUtils; the methods getSpringConfigFilePaths and closeDataSources must be extended as well. The former provide the path for the configuration files of the new service needed by Spring, the latter handles the database connection closure of the new datasources.Create a java class <PROJECT_NAME>ApsAdminTestCase (inside the package test.it.projectname.apsadmin) which extends the class test.com.agiletec.apsadmin.ApsAdminTestCase, then override the method getConfigUtils (so that it returns an instance of the class previously created) and the setInitParameters (so to load the definition of your actions and all those defined in the same level of the struts.xml)
Create the Action classes named Test<NAME_OF_THE_HANDLED_OBJECT>Action which extends the class of the previous step. If needed create the test class of the action which uses the search engine of your service; always test all the Actions!
All the jsp files composing the user interfaces are located in the directory /WEB-INF/<PROJECT_NAME>/apsadmin/jsp/.
Example 4.15. jsp of the card manager service
cardFinder.jsp: this is the interface for the search card service; the search itself is handled by the Action class CardFinderAction.entryCard.jspgenerates the Card add/remove interface, handled by the Action class CardAction.
The (jsp) interfaces must be declared inside the template called main.layout in the file
/WEB-INF/apsadmin/tiles.xml which specifies the configuration of the pages being invoked
as a result of the action. Such configuration must obey the rules of Tiles2, a Struts2 plugin.
Define a new Tiles configuration file for the pages, <PROJECT_NAME>-tiles.xml inside the folder
/WEB-INF/<PROJECT_NAME>/apsadmin.
The pages must extend the main.layout and the single ids represent the result (in the form of
tiles type) of every action.
The tiles configuration must be declared within the parameter org.apache.tiles.impl.BasicTilesContainer.DEFINITIONS_CONFIG
of the descritptor file web.xml of the web application. Again, it must be placed in the last position.
To add a new element in the Plugin menu create in the directory
/WEB-INF/<PROJECT_NAME>/apsadmin/jsp/common/template/ a file named
subMenu.jsp which contains the new menu item referring to the new application service
(a plugin, in this case)
Then create a new bean (a Spring Object) with id <SERVICE_NAME>SubMenu which refers to the class
PluginSubMenuContainer; this class has a property called submenuFilePath whose value
is the path of the subMenu.jsp just created.
Example 4.16. Declaration of the Menu
<bean id="cardPluginSubMenu" class="com.agiletec.apsadmin.system.plugin.PluginSubMenuContainer" > <property name="subMenuFilePath"> <value>/WEB-INF/demo/apsadmin/jsp/common/template/subMenu.jsp</value> </property> </bean>
Following carefully these steps the new menu item will be included in the Plugin menu in the
administration area.
If the Application service is going to modify exinsting interfaces for any reason (eg. integration of new modules, link or whatever) you are adviced to avoid any modification of the Core interfaces. Create instead in the tiles configuration file <PROJECT_NAME>-tiles.xml a new definition with the same name of the core interface to override. So the element to modify is simply rewritten from scratch.
Example 4.17. Redefinition of the "Pages Tree" interface
copy the following definition in the files <PROJECT_NAME>-tiles.xml:
<definition extends="main.layout" name="admin.Page.viewTree"> <put-attribute name="title" value="title.pageManagement" /> <put-attribute name="extraResources" value="/WEB-INF/apsadmin/jsp/common/template/extraresources/pageTree.jsp" /> <put-attribute name="body" value="/WEB-INF/<PROJECT_NAME>/apsadmin/jsp/page/pageTree.jsp" /> </definition>
where the admin.Page.viewTree is the id of the interface of the page tree handler.
The path of the jsp must be the same of the jsp files of the interface to extend with the solely exclusion
of the root directory of your project.
Nei limiti del possibile, è sconsigliato utilizzare questa tecnica; nel caso di inserimento nuove
funzionalità che integrano alcune preesistenti,
è consigliato utilizzare la tecnica dei SubMenu dei Plugin per creare gli
EntryPoint della funzionalità.
Whenever it's possible please follow these directions; if the new service adds some new functionality
extentending the existing ones, a good practice is to use the submenu technique used for the plugins
so to create the entry point for the new service.
