Apache DeltaSpike

Proxy Module

Overview

The Proxy Module provides a simple CDI based wrapper for creating dynamic proxies that can be used within other extensions.
The benefit of the DeltaSpike Proxy Module (compared to Javassist or any library) is that the DeltaSpike proxies will execute CDI interceptors.
The Proxy Module also provides the 'DeltaSpikeProxyContextualLifecycle', which enables you to dynamically register a proxy as CDI bean via the DeltaSpike 'BeanBuilder'.

Currently CDI Interceptors applied via @Interceptors, @Intercepted and @Decorator are not supported by our proxies!

1. Declare Proxy Module Dependencies

Add the Proxy module to the list of dependencies in the project pom.xml file using this code snippet:

<dependency>
    <groupId>org.apache.deltaspike.modules</groupId>
    <artifactId>deltaspike-proxy-module-api</artifactId>
    <version>${deltaspike.version}</version>
    <scope>compile</scope>
</dependency>

<dependency>
    <groupId>org.apache.deltaspike.modules</groupId>
    <artifactId>deltaspike-proxy-module-impl-asm</artifactId>
    <version>${deltaspike.version}</version>
    <scope>runtime</scope>
</dependency>

Or if you’re using Gradle, add these dependencies to your build.gradle:

     runtime 'org.apache.deltaspike.modules:deltaspike-proxy-module-impl'
     compile 'org.apache.deltaspike.modules:deltaspike-proxy-module-api'

The currently provided implementation is a wrapper for ASM 5, which gets shaded into the implementation JAR.

2. Extend DeltaSpikeProxyFactory

The key to making the proxy module work is to provide an implementation of DeltaSpikeProxyFactory which will do your proxy work for you.
DeltaSpike ships 3 implementations which demonstrates how its meant to work:

  • org.apache.deltaspike.partialbean.impl.PartialBeanProxyFactory

  • org.apache.deltaspike.proxy.util.EnableInterceptorsProxyFactory

  • org.apache.deltaspike.jsf.impl.injection.proxy.ConverterAndValidatorProxyFactory

3. Using @EnableInterceptors

@EnableInterceptors allows you to enable your bean interceptors for @Produces, which is not supported via the CDI API.
Both interceptors on method and class level are supported.

@MyCustomInterceptor
public SomeServiceImpl implements SomeService
{
    @Transactional
    public void doSomething()
    {
        ....
    }
}
@Produces
@EnableInterceptors
public SomeService produce()
{
    return new SomeServiceImpl();
}

4. Using EnableInterceptorsProxyFactory

@EnableInterceptors is just a API for producers which is built on EnableInterceptorsProxyFactory.
With EnableInterceptorsProxyFactory you can just proxy an existing object and let it execute CDI interceptors, if they are defined on the given object class.

@MyCustomInterceptor
public SomeServiceImpl implements SomeService
{
    @Transactional
    public void doSomething()
    {
        ....
    }
}
public void init()
{
    SomeServiceImpl myService = new SomeServiceImpl();
    myService = EnableInterceptorsProxyFactory.wrap(myService, BeanManagerProvider.getInstance().getBeanManager());
    myService.doSomething(); // will execute the interceptors
}