spring-framework/spring-framework-reference/src/new-in-3.xml

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<chapter id="new-in-3">
  <title>What's new in Spring 3.0?</title>

  <para>If you have been using the Spring Framework for some time, you will be
  aware that Spring has undergone two major revisions: Spring 2.0, released in
  October 2006, and Spring 2.5, released in November 2007. It is now time for
  a third overhaul resulting in Spring 3.0.</para>

  <sidebar id="new-in-3-intro-java">
    <title>Java SE and Java EE Support</title>

    <para>The Spring Framework is now based on Java 5 and Java 6 is fully
    supported.</para>

    <para>Furthermore, Spring is compatible with J2EE 1.4 and Java EE 5, while
    at the same time introducing some early support for Java EE 6.</para>
  </sidebar>

  <section id="new-in-3-intro">
    <title>Java 5</title>

    <para>The entire framework code has been revised to take advantage of Java
    5 features like generics, varargs and other language improvements. We have
    done our best to still keep the code backwards compatible. We now have
    consistent use of generic Collections and Maps, consistent use of
    generified FactoryBeans, and also consistent resolution of bridge methods
    in the Spring AOP API. Generified ApplicationListeners automatically
    receive specific event types only. All callback interfaces such as
    TransactionCallback and HibernateCallback declare a generic result value
    now. Overall, the Spring core codebase is now freshly revised and
    optimized for Java 5.</para>

    <para>Spring's TaskExecutor abstraction has been updated for close
    integration with Java 5's java.util.concurrent facilities. We provide
    first-class support for Callables and Futures now, as well as
    ExecutorService adapters, ThreadFactory integration, etc. This has been
    aligned with JSR-236 (Concurrency Utilities for Java EE 6) as far as
    possible. Furthermore, we provide support for asynchronous method
    invocations through the use of the new @Async annotation (or EJB 3.1's
    @Asynchronous annotation).</para>
  </section>

  <section id="new-in-3-improved-docs">
    <title>Improved documentation</title>

    <sidebar id="new-in-3-intro-work-in-progress">
      <title>Note:</title>

      <para>The current documentation is a <emphasis>*** WORK IN PROGRESS
      ***</emphasis> and is currently being re-written to reflect all the
      changes in the framework and from now relying on Java 5 features.</para>
    </sidebar>

    <para>The Spring reference documentation has also substantially been
    updated to reflect all of the changes and new features for Spring 3.0.
    While every effort has been made to ensure that there are no errors in
    this documentation, some errors may nevertheless have crept in. If you do
    spot any typos or even more serious errors, and you can spare a few cycles
    during lunch, please do bring the error to the attention of the Spring
    team by <ulink url="http://jira.springframework.org/">raising an
    issue</ulink>.</para>
  </section>

  <section id="new-in-3-modules-build">
    <title>New module organization and build system</title>

    <para>The framework modules have been revised and are now managed
    separately with one source-tree per module jar:</para>

    <itemizedlist>
      <listitem>
        <para>org.springframework.aop</para>
      </listitem>

      <listitem>
        <para>org.springframework.beans</para>
      </listitem>

      <listitem>
        <para>org.springframework.context</para>
      </listitem>

      <listitem>
        <para>org.springframework.context.support</para>
      </listitem>

      <listitem>
        <para>org.springframework.expression</para>
      </listitem>

      <listitem>
        <para>org.springframework.instrument</para>
      </listitem>

      <listitem>
        <para>org.springframework.jdbc</para>
      </listitem>

      <listitem>
        <para>org.springframework.jms</para>
      </listitem>

      <listitem>
        <para>org.springframework.orm</para>
      </listitem>

      <listitem>
        <para>org.springframework.oxm</para>
      </listitem>

      <listitem>
        <para>org.springframework.test</para>
      </listitem>

      <listitem>
        <para>org.springframework.transaction</para>
      </listitem>

      <listitem>
        <para>org.springframework.web</para>
      </listitem>

      <listitem>
        <para>org.springframework.web.portlet</para>
      </listitem>

      <listitem>
        <para>org.springframework.web.servlet</para>
      </listitem>
    </itemizedlist>

    <sidebar id="new-in-3-intro-spring-jar">
      <title>Note:</title>

      <para>The spring.jar artifact that contained almost the entire framework
      is no longer provided.</para>
    </sidebar>

    <para>We are now using a new Spring build system as known from Spring Web
    Flow 2.0. This gives us:</para>

    <itemizedlist>
      <listitem>
        <para>Ivy-based "Spring Build" system</para>
      </listitem>

      <listitem>
        <para>consistent deployment procedure</para>
      </listitem>

      <listitem>
        <para>consistent dependency management</para>
      </listitem>

      <listitem>
        <para>consistent generation of OSGi manifests</para>
      </listitem>
    </itemizedlist>
  </section>

  <section id="new-in-3-features-overview">
    <title>Overview of new features</title>

    <para>This is a list of new features for Spring 3.0. We will cover these
    features in more detail later in this section.</para>

    <itemizedlist>
      <listitem>
        <para>Spring Expression Language</para>
      </listitem>

      <listitem>
        <para>IoC enhancements/Spring JavaConfig</para>
      </listitem>

      <listitem>
        <para>Comprehensive REST support</para>
      </listitem>

      <listitem>
        <para>@MVC additions</para>
      </listitem>

      <listitem>
        <para>Declarative model validation</para>
      </listitem>

      <listitem>
        <para>Early support for Java EE 6</para>
      </listitem>
    </itemizedlist>

  <section id="new-feature-java5">
    <title>Core APIs updated for Java 5</title>

    <para>BeanFactoryinterface returns typed bean 
	instancesas far as possible
	<itemizedlist>
		<listitem><para>T getBean(Stringname, Class&lt;T&gt; requiredType)</para></listitem> 
		<listitem><para>Map&lt;String, T&gt; getBeansOfType(Class&lt;T&gt; type)</para></listitem> 
	</itemizedlist>
	</para>
	
	<para>Spring's TaskExecutorinterface extends 
	<classname>java.util.concurrent.Executor</classname> now
	<itemizedlist>
		<listitem><para>extended AsyncTaskExecutor supports standard Callables with Futures</para></listitem> 
	</itemizedlist>
	</para>
	
	<para>New Java 5 based converter API and SPI 
	<itemizedlist>
		<listitem><para>stateless ConversionService and Converters</para></listitem> 
		<listitem><para>superseding standard JDK PropertyEditors</para></listitem> 
	</itemizedlist>
	</para>
	
	<para>Typed ApplicationListener&lt;E&gt;
	</para>
	
  </section>

  <section id="new-feature-el">
    <title>Spring Expression Language</title>

    <para>Spring introduces an expression language which is similar to Unified
    EL in its syntax but offers significantly more features. The expression
    language can be used when defining XML and Annotation based bean
    definitions and also serves as the foundation for expression language
    support across the Spring portfolio. Details of this new functionality can
    be found in the chapter <link linkend="expressions">Spring Expression
    Language (SpEL).</link></para>

	<para>The Spring Expression Language was created to provide the Spring community with a single well 
	supported expression language that can used across all the products in the Spring portfolio. Its language 
	features are driven by the requirements of the projects in the Spring portfolio, including tooling 
	requirements for code completion support within the eclipse based SpringSource Tool Suite.</para>
	
	<para>The following is an example of how the Expression Language can be used to configure some properties 
	of a database setup
	<programlisting language="xml"><![CDATA[<bean class="mycompany.RewardsTestDatabase">
    <property name="databaseName"
        value="#{systemProperties.databaseName}"/>
    <property name="keyGenerator"
        value="#{strategyBean.databaseKeyGenerator}"/>
</bean>
]]></programlisting>
	</para>
	<para>This functionality is also available if you prefer to configure your components using
	annotations:
	<programlisting language="java"><![CDATA[@Repository 
public class RewardsTestDatabase {

    @Value("#{systemProperties.databaseName}")
    public void setDatabaseName(String dbName) { … }

    @Value("#{strategyBean.databaseKeyGenerator}")
    public voidsetKeyGenerator(KeyGenerator kg) { … }
}
]]></programlisting>
	</para>
  </section>

  <section id="new-feature-java-config">
    <title>The Inversion of Control (IoC) container</title>

    <para>Some core JavaConfig features have been added to the Spring Framework now. This means that the following
	annotations are now directly supported:
	
	<itemizedlist>
		<listitem><para>@Configuration</para></listitem> 
		<listitem><para>@Bean</para></listitem> 
		<listitem><para>@Primary</para></listitem> 
		<listitem><para>@Lazy</para></listitem> 
		<listitem><para>@Import</para></listitem> 
		<listitem><para>@Value</para></listitem> 
	</itemizedlist>
	</para>

	<para>
	Here is an example of a Java class providing basic configuration using the new JavaConfig features:
	<programlisting language="java"><![CDATA[@Configuration 
public class AppConfig{ 
    @Value("#{jdbcProperties.url}") String jdbcUrl; 
    @Value("#{jdbcProperties.username}") String username; 
    @Value("#{jdbcProperties.password}") String password; 

    @Bean 
    public FooServicefooService() { 
        return new FooServiceImpl(fooRepository()); 
    }

    @Bean 
    public FooRepositoryfooRepository() { 
        return new HibernateFooRepository(sessionFactory()); 
    }

    @Bean 
    public SessionFactorysessionFactory() { 
        // wire up a session factory using 
        // AnnotationSessionFactoryBean 
        asFactoryBean.setDataSource(dataSource()); 
        return (SessionFactory) asFactoryBean.getObject(); 
    } 

    @Bean 
    public DataSourcedataSource() { 
        return new DriverManagerDataSource(jdbcUrl, 
        username, password); 
    } 
}
]]></programlisting>

	To get this to work you need to add the following component scanning entry in your minimal
	application context XML file.
	
	<programlisting language="java"><![CDATA[<context:component-scan 
    base-package="com.myco.config"/>]]></programlisting>
	
	</para>

  </section>

  <section id="new-feature-rest">
    <title>The Web Tier</title>

    <para>Work in progress ...</para>

    <section>
      <title>Comprehensive REST support</title>

      <para>Work in progress ...</para>
    </section>

    <section>
      <title>@MVC additions</title>

      <para>Work in progress ...</para>
    </section>
  </section>

  <section id="new-feature-validation">
    <title>Declarative model validation</title>

    <para>Hibernate Validator, JSR 303</para>
  </section>

  <section id="new-feature-jee-6">
    <title>Early support for Java EE 6</title>

    <para>JSF 2.0, JPA 2.0, etc</para>
  </section>
  </section>

</chapter>