How to configure with Spring an api not based on Spring

HOW TO CONFIGURE WITH SPRING AN API NOT BASED ON SPRING Jose María Arranz Santamaría Madrid (Spain) February 17-18, 2011 1

THE PROBLEM 2

THE PROBLEM• Spring was born as a tool to configure and integrate disparate technologies• We can not always expect such disparate technologies be ready to be configured “out of the box” with Spring This is the thing Spring was invented for! 3

EL PROBLEMA• ItsNat is a Java web framework with a custom non-Spring configuration system• ItsNat configuration is the most powerful and flexible approach ever invented: Calling methods!• As of day 0 ItsNat configuration was conceived to be “overloaded” with higher level configuration techniques and APIs, for instance… Spring! 4

DO NOT WORRY THIS IS NOT GOING TO BE AN ItsNat COURSE!  6

WE ARE GOING TO LEARN SOME Spring TRICKS 7

BUT WE MUST KNOW HOW TO CONFIGURE A WEB PROJECT BASED ON ItsNat TO CONFIGURE IT LATER WITH SpringWe will pick the “core” example in the ItsNat Reference Manual 8

“PURE” ItsNat EXAMPLE: the servlet• ItsNat does not define a concrete servlet, developer must create one (or more) – Configuration is done in method init • In this example most of configuration is optional, just used to show ItsNat configuration optionspublic class servlet extends HttpServletWrapper{ public void init(ServletConfig config) throws ServletException { super.init(config); ItsNatHttpServlet itsNatServlet = getItsNatHttpServlet(); ItsNatServletConfig itsNatConfig = itsNatServlet.getItsNatServletConfig(); ItsNatServletContext itsNatCtx = itsNatConfig.getItsNatServletContext(); 9

“PURE” ItsNat EXAMPLE: the servlet• ItsNatHttpServlet, ItsNatServletConfig y ItsNatServletContext are the roots (and singletons) of ItsNat configuration itsNatCtx.setMaxOpenDocumentsBySession(6); String serverInfo = getServletContext().getServerInfo(); boolean gaeEnabled = serverInfo.startsWith( "Google App Engine"); itsNatCtx.setSessionReplicationCapable(gaeEnabled); itsNatCtx.setSessionSerializeCompressed(false); itsNatCtx.setSessionExplicitSerialize(false); 10

“PURE” ItsNat EXAMPLE: the servlet itsNatConfig.setDebugMode(true); itsNatConfig.setClientErrorMode( ClientErrorMode.SHOW_SERVER_AND_CLIENT_ERRORS); itsNatConfig.setLoadScriptInline(true); itsNatConfig.setFastLoadMode(true); itsNatConfig.setCommMode(CommMode.XHR_ASYNC_HOLD); itsNatConfig.setEventTimeout(-1); itsNatConfig.setOnLoadCacheStaticNodes("text/html",true); itsNatConfig.setOnLoadCacheStaticNodes("text/xml",false); itsNatConfig.setNodeCacheEnabled(true); 11

“PURE” ItsNat EXAMPLE: the servletitsNatConfig.setDefaultEncoding("UTF-8");itsNatConfig.setUseGZip(UseGZip.SCRIPT);itsNatConfig.setDefaultDateFormat( DateFormat.getDateInstance(DateFormat.DEFAULT,Locale.US));itsNatConfig.setDefaultNumberFormat( NumberFormat.getInstance(Locale.US));itsNatConfig.setEventDispatcherMaxWait(0);itsNatConfig.setEventsEnabled(true);itsNatConfig.setScriptingEnabled(true);itsNatConfig.setUsePatternMarkupToRender(false);itsNatConfig.setAutoCleanEventListeners(true); 12

“PURE” ItsNat EXAMPLE: the servlet• Now we register in the servlet an ItsNat template core_example.xhtml and associated document loader CoreExampleLoadListener – Just a simple example of HTML page with AJAX String pathPrefix = getServletContext().getRealPath("/"); pathPrefix += "/WEB-INF/pages/manual/"; ItsNatDocumentTemplate docTemplate; docTemplate = itsNatServlet.registerItsNatDocumentTemplate( "manual.core.example","text/html", pathPrefix + "core_example.xhtml"); docTemplate.addItsNatServletRequestListener( new CoreExampleLoadListener()); 13

“PURE” ItsNat EXAMPLE: the servlet• Another example, in this case a page with XML docTemplate = itsNatServlet.registerItsNatDocumentTemplate( "manual.core.xmlExample","text/xml", pathPrefix + "xml_example.xml"); docTemplate.addItsNatServletRequestListener( new CoreXMLExampleLoadListener());• This XML example inserts an ItsNat “template fragment” – Template fragments have not “loaders/processors” ItsNatDocFragmentTemplate docFragTemplate; docFragTemplate = itsNatServlet.registerItsNatDocFragmentTemplate( "manual.core.xmlFragExample","text/xml", pathPrefix + "xml_fragment_example.xml"); 14

“PURE” ItsNat EXAMPLE• <root>/WEB-INF/pages/manual/core_example.xhtml<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>ItsNat Core Example</title></head><body> <h3>ItsNat Core Example</h3> <div itsnat:nocache="true" xmlns:itsnat="http://itsnat.org/itsnat"> <div id="clickableId1">Clickable Elem 1</div> <br /> <div id="clickableId2">Clickable Elem 2</div> </div></body></html> 15

“PURE” ItsNat EXAMPLE• CoreExampleLoadListener is just a simple launcher of document processors, called per page loadedpublic class CoreExampleLoadListener implements ItsNatServletRequestListener{ public CoreExampleLoadListener() {} public void processRequest(ItsNatServletRequest request, ItsNatServletResponse response) { ItsNatHTMLDocument itsNatDoc = (ItsNatHTMLDocument)request.getItsNatDocument(); new CoreExampleDocument(itsNatDoc); }} 16

“PURE” ItsNat EXAMPLE• CoreExampleDocument manages the page (document) state receiving AJAX eventspublic class CoreExampleDocument implements EventListener{ protected ItsNatHTMLDocument itsNatDoc; protected Element clickElem1; protected Element clickElem2; public CoreExampleDocument(ItsNatHTMLDocument itsNatDoc) { this.itsNatDoc = itsNatDoc; load(); } ... 17

“PURE” ItsNat EXAMPLE 18

“PURE” ItsNat EXAMPLE• <root>/WEB-INF/pages/manual/xml_example.xml<?xml version=1.0 encoding=UTF-8 ?><discs> <itsnat:include name="manual.core.xmlFragExample" xmlns:itsnat="http://itsnat.org/itsnat" /> <cdList> <cd> <title>Tittle</title> <artist>Artist</artist> <songs> <song>Song Pattern</song> </songs> </cd> </cdList></discs> 19

“PURE” ItsNat EXAMPLE• <root>/WEB-INF/pages/manual/xml_fragment_example.xml<?xml version=1.0 encoding=UTF-8 ?><root> <title>CD List</title> <subtitle>in XML</subtitle></root> 20

“PURE” ItsNat EXAMPLE• CoreXMLExampleLoadListener : in this case (XML page) there is no AJAX events, we do not need a class wrapping the document. This example includes the template fragment "manual.core.xmlFragExample"public class CoreXMLExampleLoadListener implements ItsNatServletRequestListener{ public CoreXMLExampleLoadListener() { } public void processRequest(ItsNatServletRequest request, ItsNatServletResponse response) { ItsNatDocument itsNatDoc = request.getItsNatDocument(); Document doc = itsNatDoc.getDocument(); Element discsElem = doc.getDocumentElement(); ... 21

“PURE” ItsNat EXAMPLE 22

ItsNat Springization 23

OBJETIVES1. Build a single reused generic servlet : itsnatspring.itsnatservlet2. Configuration is fully done in a XML configuration file of Spring in classpath: itsnatex/spring.xml3. The only user defined Java classes will be the document wrappers/containers: itsnatex.CoreExampleDocument itsnatex.CoreXMLExampleDocument 24

CONSEQUENCES• Besides the generic servlet we will need some utility classes also generic and reusable for other ItsNat+Spring projects• These classes are not completed, just to cover the needs of this example – ItsNat has more configuration options 25

THE SERVLETpackage itsnatspring;import javax.servlet.ServletConfig;import javax.servlet.ServletException;import org.itsnat.core.http.HttpServletWrapper;import org.itsnat.core.http.ItsNatHttpServlet;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import org.springframework.context.support.GenericApplicationContext;public class itsnatservlet extends HttpServletWrapper{ public void init(ServletConfig config) throws ServletException { super.init(config); ItsNatHttpServlet itsNatServlet = getItsNatHttpServlet(); GenericApplicationContext rootContext = new GenericApplicationContext(); ItsNatBeansRegistryUtil.registerSingletons(rootContext, itsNatServlet); rootContext.refresh(); 26

EL SERVLET String springXMLPath = config.getInitParameter("spring_config"); if (springXMLPath == null) throw new RuntimeException("spring_config initialization parameter is not specified in web.xml"); ApplicationContext context = new ClassPathXmlApplicationContext( new String[] {springXMLPath},rootContext); }}• ItsNat configuration objects are registered into a generic ApplicationContext (the root), our XML with Spring configuration is loaded by another (child) Spring context 27

ItsNatBeansRegistryUtilpackage itsnatspring;import org.itsnat.core.ItsNatServletConfig;import org.itsnat.core.ItsNatServletContext;import org.itsnat.core.http.ItsNatHttpServlet;import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;import org.springframework.context.ApplicationContext;import org.springframework.context.support.AbstractApplicationContext;public class ItsNatBeansRegistryUtil{ public final static String itsNatHttpServletBean = "itsNatHttpServlet"; public final static String itsNatServletConfigBean = "itsNatServletConfig"; public final static String itsNatServletContextBean = "itsNatServletContext"; public static ItsNatHttpServlet getItsNatHttpServlet(ApplicationContext context) { return context.getBean(itsNatHttpServletBean,ItsNatHttpServlet.class); } public static ItsNatServletConfig getItsNatServletConfig(ApplicationContext context){ return context.getBean(itsNatServletConfigBean,ItsNatServletConfig.class); } public static ItsNatServletContext getItsNatServletContext(ApplicationContext context){ return context.getBean(itsNatServletContextBean,ItsNatServletContext.class); } 28

ItsNatBeansRegistryUtil public static void registerSingletons(AbstractApplicationContext context, ItsNatHttpServlet itsNatServlet) { ItsNatServletConfig itsNatServletCofig = itsNatServlet.getItsNatServletConfig(); ItsNatServletContext itsNatServletContext = itsNatServletCofig.getItsNatServletContext(); ConfigurableListableBeanFactory beanFact = context.getBeanFactory(); beanFact.registerSingleton(itsNatHttpServletBean,itsNatServlet); beanFact.registerSingleton(itsNatServletConfigBean,itsNatServletCofig); beanFact.registerSingleton(itsNatServletContextBean,itsNatServletContext); }}• ItsNat configuration objects are manually registered as singletons in Spring context 29

web.xml<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <servlet> <servlet-name>itsnatservlet</servlet-name> <servlet-class>itsnatspring.itsnatservlet</servlet-class> <init-param> <param-name>spring_config</param-name> <param-value>itsnatex/spring.xml</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>itsnatservlet</servlet-name> <url-pattern>/itsnatservlet</url-pattern> </servlet-mapping> <session-config> <session-timeout>30</session-timeout> </session-config></web-app> 30

spring.xml<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd"><bean class="itsnatspring.ItsNatServletContextBean"> <property name="maxOpenDocumentsBySession" value="10" /> <property name="sessionReplicationCapable" value="false" /> <property name="sessionSerializeCompressed" value="false" /> <property name="sessionExplicitSerialize" value="false" /></bean> 31

ItsNatServletContextBean• This utility class is used as a singleton to save the specified flags and in the end of bean configuration they are registered calling methods of ItsNatServletContext – Because we need the ApplicationContext we will implement ApplicationContextAware – Because we must to save in ItsNat context our configuration data in the end of bean configuration we need to implement InitializingBean 32

ItsNatServletContextBeanpackage itsnatspring;import org.itsnat.core.ItsNatServletContext;import org.springframework.beans.BeansException;import org.springframework.beans.factory.InitializingBean;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;public class ItsNatServletContextBean implements InitializingBean,ApplicationContextAware{ protected ApplicationContext context; protected Integer maxOpenDocumentsBySession; protected Boolean sessionReplicationCapable; protected Boolean sessionSerializeCompressed; protected Boolean sessionExplicitSerialize; public ItsNatServletContextBean() { } 33

ItsNatServletContextBeanpublic int getMaxOpenDocumentsBySession() { return maxOpenDocumentsBySession;}public void setMaxOpenDocumentsBySession(int maxOpenDocumentsBySession){ this.maxOpenDocumentsBySession = maxOpenDocumentsBySession;}public boolean getSessionReplicationCapable() { return sessionReplicationCapable;}public void setSessionReplicationCapable( boolean sessionReplicationCapable) { this.sessionReplicationCapable = sessionReplicationCapable;}public boolean getSessionSerializeCompressed() { return sessionSerializeCompressed;}public void setSessionSerializeCompressed( boolean sessionSerializeCompressed) { this.sessionSerializeCompressed = sessionSerializeCompressed;} 34

ItsNatServletContextBean public boolean getSessionExplicitSerialize() { return sessionExplicitSerialize; } public void setSessionExplicitSerialize(boolean sessionExplicitSerialize){ this.sessionExplicitSerialize = sessionExplicitSerialize; } @Override public void setApplicationContext(ApplicationContext context) throws BeansException { this.context = context; } @Override public void afterPropertiesSet() throws Exception { ItsNatServletContext itsNatServletContext = ItsNatBeansRegistryUtil.getItsNatServletContext(context); if (maxOpenDocumentsBySession != null) itsNatServletContext.setMaxOpenDocumentsBySession(maxOpenDocumentsBySession); if (sessionReplicationCapable != null) itsNatServletContext.setSessionReplicationCapable(sessionReplicationCapable); if (sessionSerializeCompressed != null) itsNatServletContext.setSessionSerializeCompressed(sessionSerializeCompressed); if (sessionExplicitSerialize != null) itsNatServletContext.setSessionExplicitSerialize(sessionExplicitSerialize); }} 35

spring.xml (cont.)<bean id="defaultLocale" class="itsnatspring.LocaleBean" > <property name="language" value="en" /> <property name="country" value="US" /></bean><bean id="defaultDateFormat" class="itsnatspring.DateFormatBean" > <property name="style" value="2" />  <property name="locale"> <bean factory-bean="defaultLocale" factory-method="getLocale"/> </property></bean><bean id="defaultNumberFormat" class="itsnatspring.NumberFormatBean" > <property name="locale"> <bean factory-bean="defaultLocale" factory-method="getLocale" /> </property></bean>... 36

LocaleBean• This “factory bean” allows configuring a Locale and made public calling the “factory method” getLocale()package itsnatspring;import java.util.Locale;import org.springframework.beans.factory.InitializingBean;public class LocaleBean implements InitializingBean{ protected String language; protected String country; protected Locale locale; public LocaleBean() { } public String getCountry() { return country; } public void setCountry(String country) { this.country = country; } public String getLanguage() { return language; } 37

LocaleBean public void setLanguage(String language) { this.language = language; } public Locale getLocale() { return locale; } @Override public void afterPropertiesSet() throws Exception { Locale[] availablelocales = Locale.getAvailableLocales(); for(Locale locale : availablelocales) if (locale.getLanguage().equals(language) && locale.getCountry().equals(country)) { this.locale = locale; return; } this.locale = new Locale(language,country); }} 38

• Some other utility classes are very similar to the previous shown, from now we are just to show only the most interesting• From Spring XML you can figure out how they work under the hood – ItsNat singletons are got through ItsNatBeansRegistryUtil and the Spring ApplicationContext – This context is got implementing ApplicationContextAware 39

spring.xml (cont.)<bean class="itsnatspring.ItsNatServletConfigBean"> <property name="debugMode" value="true" /> <property name="clientErrorMode" value="4" /> <!– ClientErrorMode.SHOW_SERVER_AND_CLIENT_ERRORS --> <property name="defaultEncoding" value="UTF-8" /> <property name="onLoadCacheStaticNodes"> <!– backed by a Properties attr --> <value> text/html=true text/xml=false </value> </property> <property name="defaultDateFormat"> <bean factory-bean="defaultDateFormat" factory-method="getDateFormat"/> </property> <property name="defaultNumberFormat"> <bean factory-bean="defaultNumberFormat" factory-method="getNumberFormat"/> </property></bean> ... 40

spring.xml (cont.)<bean id="coreExamplePath" class="itsnatspring.WebPathBean"> <property name="relativePath" value="/WEB-INF/pages/manual/core_example.xhtml"/></bean><bean id="coreExampleDoc" class="itsnatex.CoreExampleDocument" scope="prototype" > </bean><bean id="coreExampleDocTemplate" class="itsnatspring.ItsNatDocumentTemplateBean"> <property name="name" value="manual.core.example" /> <property name="mime" value="text/html" /> <property name="source"> <bean factory-bean="coreExamplePath" factory-method="getAbsolutePath"/> </property> <property name="itsNatServletRequestListener" > <bean class="itsnatspring.ItsNatServletRequestListenerBean" > <property name="documentBeanName" value="coreExampleDoc" /> </bean> </property></bean> ... 41

ItsNatServletRequestListenerBean• This “local singleton bean” is very interesting becase it works like a generic “ItsNat document loader listener” implementing ItsNatServletRequestListener• To be generic we must invent a simple interface ItsNatDocumentInitialize for the document processors/wrappers:package itsnatspring;import org.itsnat.core.ItsNatServletRequest;import org.itsnat.core.ItsNatServletResponse;public interface ItsNatDocumentInitialize{ public void load(ItsNatServletRequest request, ItsNatServletResponse response);} 42

ItsNatServletRequestListenerBeanpackage itsnatspring;import org.itsnat.core.ItsNatServletRequest;import org.itsnat.core.ItsNatServletResponse;import org.itsnat.core.event.ItsNatServletRequestListener;import org.springframework.beans.BeansException;import org.springframework.beans.factory.InitializingBean;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import org.springframework.context.support.AbstractApplicationContext;public class ItsNatServletRequestListenerBean implements ItsNatServletRequestListener,ApplicationContextAware,InitializingBean{ protected AbstractApplicationContext context; protected String documentBeanName; public ItsNatServletRequestListenerBean() { } 43

ItsNatServletRequestListenerBeanpublic void processRequest(ItsNatServletRequest request, ItsNatServletResponse response) { ItsNatDocumentInitialize docWrapper = context.getBean(documentBeanName,ItsNatDocumentInitialize.class); docWrapper.load(request, response); } public String getDocumentBeanName() { return documentBeanName; } public void setDocumentBeanName(String documentBeanName) { this.documentBeanName = documentBeanName; } 44

ItsNatServletRequestListenerBean @Override public void setApplicationContext(ApplicationContext context) throws BeansException { this.context = (AbstractApplicationContext)context; } @Override public void afterPropertiesSet() throws Exception { // Checking correctly defined: if (documentBeanName == null) throw new RuntimeException("docBeanName property is mandatory"); if (!context.getBeanFactory().isPrototype(documentBeanName)) throw new RuntimeException("Bean " + documentBeanName + " must be "prototype" scoped"); }} 45

ItsNatDocumentTemplateBean• Finally this bean registers the template and the associated “ItsNat document loader listener” configuredpackage itsnatspring;import org.itsnat.core.event.ItsNatServletRequestListener;import org.itsnat.core.http.ItsNatHttpServlet;import org.itsnat.core.tmpl.ItsNatDocumentTemplate;import org.springframework.beans.BeansException;import org.springframework.beans.factory.InitializingBean;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;public class ItsNatDocumentTemplateBean implements InitializingBean,ApplicationContextAware { protected ApplicationContext context; protected String name; protected String mime; protected Object source; protected ItsNatServletRequestListener itsNatServletRequestListener; 46

ItsNatDocumentTemplateBean public ItsNatServletRequestListener getItsNatServletRequestListener(){ return itsNatServletRequestListener; } public void setItsNatServletRequestListener( ItsNatServletRequestListener itsNatServletRequestListener) { this.itsNatServletRequestListener = itsNatServletRequestListener; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getMime() { return mime; } public void setMime(String mime) { this.mime = mime; } public Object getSource() { return source; } public void setSource(Object source) { this.source = source; }@Override public void setApplicationContext(ApplicationContext context) throws BeansException { this.context = context; } 47

ItsNatDocumentTemplateBean @Override public void afterPropertiesSet() throws Exception { // name, mime and source are mandatory ItsNatHttpServlet itsNatHttpServlet = ItsNatBeansRegistryUtil.getItsNatHttpServlet(context); ItsNatDocumentTemplate docTemplate = itsNatHttpServlet.registerItsNatDocumentTemplate(name,mime,source); if (itsNatServletRequestListener != null) docTemplate.addItsNatServletRequestListener( itsNatServletRequestListener); // More config here... }} 48

spring.xml (cont.)<bean id="coreXMLDocExamplePath" class="itsnatspring.WebPathBean"> <property name="relativePath" value="/WEB-INF/pages/manual/xml_example.xml" /></bean><bean id="coreXMLExampleDoc" class="itsnatex.CoreXMLExampleDocument“ scope="prototype"> </bean><bean id="coreXMLExampleDocTemplate" class="itsnatspring.ItsNatDocumentTemplateBean"> <property name="name" value="manual.core.xmlExample" /> <property name="mime" value="text/xml" /> <property name="source"> <bean factory-bean="coreXMLDocExamplePath" factory-method="getAbsolutePath"/> </property> <property name="itsNatServletRequestListener" > <bean class="itsnatspring.ItsNatServletRequestListenerBean" > <property name="documentBeanName" value="coreXMLExampleDoc" /> </bean> </property></bean> ... 49

spring.xml (cont.)<bean id="coreXMLFragExamplePath" class="itsnatspring.WebPathBean"> <property name="relativePath" value="/WEB-INF/pages/manual/xml_fragment_example.xml" /></bean><bean id="coreXMLExampleFragTemplate" class="itsnatspring.ItsNatDocFragmentTemplateBean"> <property name="name" value="manual.core.xmlFragExample" /> <property name="mime" value="text/xml" /> <property name="source"> <bean factory-bean="coreXMLFragExamplePath" factory-method="getAbsolutePath"/> </property></bean></beans> 50

ItsNatDocFragmentTemplateBean• With this class the template fragment is registered...public class ItsNatDocFragmentTemplateBean implements InitializingBean,ApplicationContextAware{ protected ApplicationContext context; protected String name; protected String mime; protected Object source;... @Override public void afterPropertiesSet() throws Exception { // name, mime and source are mandatory ItsNatHttpServlet itsNatHttpServlet = ItsNatBeansRegistryUtil.getItsNatHttpServlet(context); ItsNatDocFragmentTemplate fragTemplate; fragTemplate = itsNatHttpServlet.registerItsNatDocFragmentTemplate( name,mime,source); // More config here... }} 51

CONCLUSIONCan you use Spring to configure “any” API? 52

YES, YOU CAN! 53

QUESTIONS? 54

How to configure with Spring an api not based on Spring

by Jose María Arranz

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