Date: 2004-10-11T08:26:10 Editor: DewiRoberts <[EMAIL PROTECTED]> Wiki: Cocoon Wiki Page: SpringBeansFromFlowScript URL: http://wiki.apache.org/cocoon/SpringBeansFromFlowScript
no comment New Page: ##language:en == Spring Framework from FlowScript == This is a short introduction on how you can access Spring Framework beans from your flowscript. See http://www.springframework.org for more information about Spring, and the SpringPetstore example. === Why use Spring? === Spring lets you configure and instantiate Java objects using an ''application context'' XML file. This can be a simple list of your ''Singleton'' Java classes for which there should only ever be one instance created throughout the entire application. An example of a Singleton would be a class which interacts with a database - each instance of that class would have its own database connection, so having more than one would be a waste of resources. The Spring Framework allows you to create exactly one instance of each singleton, passing it any parameters needed; which could be a simple text value, a list of values, or a reference to another bean defined in the application context. All you have to do to let Spring inject a value is to add a setter and getter method for the properties you want set. === Example applicationContext.xml === {{{ <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd";> <beans> <!-- Define your data source --> <bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName"> <value>org.hsqldb.jdbcDriver</value> </property> <property name="url"> <value>jdbc:hsqldb:hsql://localhost:9002</value> </property> <property name="username"> <value>sa</value> </property> <property name="password"> <value></value> </property> </bean> <!-- Pass a reference to the data source to a Data Access Object --> <bean id="userDAO" class="org.myapp.UserDAOImpl"> <property name="dataSource"> <ref bean="myDataSource"/> </property> </bean> <!-- Pass a reference to the data access object to your application --> <bean id="myApp" class="org.myapp.MyAppImpl"> <property name="userDAO"> <ref bean="userDAO"/> </property> </bean> </beans> }}} === Accessing your application bean from Flowscript === Since Cocoon currently uses Avalon, you must create a wrapper object which it initializes on startup. You can then access this wrapper from your flowscript and retrieve a reference to your application bean, which has been injected with properties by Spring. {{{ public class MyAppWrapper implements Initializable { private MyAppService service; public MyAppService getService() { return service; } public synchronized void initialize() throws Exception { BeanFactoryLocator bfl = org.springframework.beans.factory.access.SingletonBeanFactoryLocator .getInstance("net/sanctuarytechnology/timesheets/spring/beanRefFactory.xml"); BeanFactory beanFactory = bfl.useBeanFactory("org.myapp.spring.appCtx").getFactory(); service = (MyAppService ) beanFactory.getBean(" LocalSessionFactoryBean lsfb = (LocalSessionFactoryBean) service.initializeDatabase(lsfb); } } }}} then in your flowscript {{{ importClass(Packages.org.myapp.MyAppWrapper); var myApp = cocoon.createObject(MyAppWrapper).service; }}}
