Question

In my Spring 3.1 application, I sometime need to change the default behavior of some of the Spring namespaces in my context files. To do that, I create custom classes that implement some interfaces or that extend the default classes Spring uses.

But I find it hard to know exactly what are those classes that Spring uses behind its namespaces! What is the steps required to find them?

For example, the security namespace :

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:sec="http://www.springframework.org/schema/security"
       xsi:schemaLocation="http://www.springframework.org/schema/beans 
                           http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                           http://www.springframework.org/schema/security 
                           http://www.springframework.org/schema/security/spring-security-3.1.xsd">

and something like :

<sec:http>
    ...
    <sec:logout />
</sec:http>

How do I find what classes are used by the “<sec:logout />” namespace? I don’t find the information by looking at http://www.springframework.org/schema/security/spring-security-3.1.xsd !

Where should I look?

Answer 1

Every Spring namespace has an associated NamespaceHandler implementation. The namespace schemas are mapped to schema files inside Spring JARs in various spring.schemas files (see also Spring DI applicationContext.xml how exactly is xsi:schemaLocation used?).

The XML schema namespaces are also mapped to handler classes in spring.handlers files (several as each Spring JAR might introduce different namespaces). For your convenience here is a list of most common namespaces:

Spring core

• aop – AopNamespaceHandler
• c – SimpleConstructorNamespaceHandler
• cache – CacheNamespaceHandler
• context – ContextNamespaceHandler
• jdbc – JdbcNamespaceHandler
• jee – JeeNamespaceHandler
• jms – JmsNamespaceHandler
• lang – LangNamespaceHandler
• mvc – MvcNamespaceHandler
• oxm – OxmNamespaceHandler
• p – SimplePropertyNamespaceHandler
• task – TaskNamespaceHandler
• tx – TxNamespaceHandler
• util – UtilNamespaceHandler

Spring Security

• security – SecurityNamespaceHandler
• oauth – OAuthSecurityNamespaceHandler

Spring integration

• int – IntegrationNamespaceHandler
• amqp – AmqpNamespaceHandler
• event – EventNamespaceHandler
• feed – FeedNamespaceHandler
• file – FileNamespaceHandler
• ftp – FtpNamespaceHandler
• gemfire – GemfireIntegrationNamespaceHandler
• groovy – GroovyNamespaceHandler
• http – HttpNamespaceHandler
• ip – IpNamespaceHandler
• jdbc – JdbcNamespaceHandler
• jms – JmsNamespaceHandler
• jmx – JmxNamespaceHandler
• mail – MailNamespaceHandler
• redis – RedisNamespaceHandler
• rmi – RmiNamespaceHandler
• script – ScriptNamespaceHandler
• security – IntegrationSecurityNamespaceHandler
• sftp – SftpNamespaceHandler
• stream – StreamNamespaceHandler
• twitter – TwitterNamespaceHandler
• ws – WsNamespaceHandler
• xml – IntegrationXmlNamespaceHandler
• xmpp – XmppNamespaceHandler

If you browse to the source of each of these classes you will quickly discover various BeanDefinitionParser implementations responsible for parsing actual XML definitions.