在nanowar中引入AOP

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  通过nanocontainer的nanowar和其struts插件完美的实现了IoC模式的透明,但无法在标准的nanowar中引入nanoaop不得不说是一种遗憾。看了一下nanocontainer的代码,决定自己动手给nanowar添加aop的支持。要在组件和实例中支持AOP,首先要引入interceptor chains。可以考虑在XML定义中引入<aspect interceptor='InterceptorName' pointcuts='Filter'/>标签。这个<aspect>标签与组件或实例的<parameter>标签在同一级别上。其中interceptor指出Lan截器的名称。Lan截器的实现可以通过标准组件方式在同一个配置文件中进行注册。pointcuts是拦截方法的过滤表达式(perl5的正则表达式,和nanoaop预定义几个过滤规则)。在nanowar中实现这个<aspect>标签,需要修改ScopedCotainerComposer, XMLContainerBuilder, ContainerRecorder, ServletContainerListener, DefaultLifecycleContainerBuider类。由于Lan截器无法在IoC容器初始化的过程中得到实例。因此,还需要引入一个新的通用Lan截器类(InterceptorDelegate),作为真正的Lan截器实例和需被拦截的组件的调用桥梁。由于对源代码改动量较大,索性就在原来类的前面加上Aspectable前缀引入新的类,但除了AOP部分,其他的保持不变。ScopedCotainerComposer => AspectableScopedContainerComposer.java    public AspectableScopedContainerComposer() throws ClassNotFoundException {        this(new DynaopAspectablePicoContainerFactory().createContainer());    }XMLContainerBuilder => AspectableXMLContainerBuilder.javaprotected PicoContainer createContainerFromScript( ....            AspectablePicoContainerFactory containerFactory = new DynaopAspectablePicoContainerFactory();            AspectablePicoContainer childContainer = containerFactory                    .createContainer(componentAdapterFactory, parentContainer);            cuts = childContainer.getPointcutsFactory(); ....}    private void registerComponentImplementation(NanoContainer container,            Element element) throws ClassNotFoundException,            MalformedURLException {    ......    Map interceptors = createInterceptors(element);    ......     if (interceptors != null) {            registerComponentInterceptor(container, clazz, interceptors);        }    }    .......    private void registerComponentInterceptor(NanoContainer container,            Class component, String pointcuts, String interceptorKey) {        if (notSet(pointcuts)) {            pointcuts = ALL_METHODS;        }        if (container.getPico() instanceof AspectablePicoContainer) {            AspectablePicoContainer aspectContainer = (AspectablePicoContainer) container                    .getPico();            aspectContainer.registerInterceptor(cuts.instancesOf(component),                    getMethodPointcut(pointcuts), new InterceptorDelegate(                            aspectContainer, interceptorKey));        }    }.......    private Map createInterceptors(Element element) {        Map interceptorMap = new HashMap();        NodeList children = element.getChildNodes();        for (int i = 0; i < children.getLength(); i++) {            if (children.item(i) instanceof Element) {                Element childElement = (Element) children.item(i);                if (ASPECT.equals(childElement.getNodeName())) {                    String interceptor = childElement.getAttribute(INTERCEPTOR);                    if (notSet(interceptor))                        throw new NanoContainerMarkupException("'" + KEY                                + "' attribute not specified for "                                + element.getNodeName());                    String pointcuts = childElement.getAttribute(POINTCUTS);                    interceptorMap.put(interceptor, pointcuts);                }            }        }        if (interceptorMap.isEmpty())            return null;        else            return interceptorMap;    }    private MethodPointcut getMethodPointcut(String pointcuts) {        if (OBJECT_METHODS.equals(pointcuts))            return cuts.objectMethods();        if (IS_METHODS.equals(pointcuts))            return cuts.isMethods();        if (ALL_METHODS.equals(pointcuts))            return cuts.allMethods();        if (GET_METHODS.equals(pointcuts))            return cuts.getMethods();        if (SET_METHODS.equals(pointcuts))            return cuts.setMethods();        return cuts.signature(pointcuts);    }ContainerRecorder => AspectableContainerRecorder.java    public MutablePicoContainer getContainerProxy() {        if (this.container instanceof AspectablePicoContainer)            return (MutablePicoContainer) Proxy.newProxyInstance(getClass().getClassLoader(),                    new Class[]{AspectablePicoContainer.class}, invocationRecorder);        else             return (MutablePicoContainer) Proxy.newProxyInstance(getClass().getClassLoader(),                new Class[]{MutablePicoContainer.class}, invocationRecorder);    }DefaultLifecycleContainerBuider => AspectableLifecycleContainerBuider.java    protected PicoContainer createContainer(PicoContainer parentContainer, Object assemblyScope) {        AspectablePicoContainerFactory containerFactory = new DynaopAspectablePicoContainerFactory();        return containerFactory.createContainer(parentContainer);    }ServletContainerListener => AspectableServletContainerListener.javaprivate ContainerBuilder createBuilder(ServletContext context)            throws ClassNotFoundException {    ......    if (initParameter.equals(CONTAINER_COMPOSER)) {        ContainerComposer containerComposer =                createContainerComposer(context);             return new AspectableLifecycleContainerBuilder(containerComposer);        }InterceptorDelegate .javaimport org.aopalliance.intercept.MethodInterceptor;import org.aopalliance.intercept.MethodInvocation;import org.picocontainer.PicoContainer;import dynaop.Interceptor;import dynaop.Invocation;public class InterceptorDelegate implements Interceptor, MethodInterceptor {    private PicoContainer pico;    private Object key;        public InterceptorDelegate(PicoContainer pico, Object key) {        this.pico = pico;        this.key = key;            }    /* (non-Javadoc)     * see dynaop.Interceptor#intercept(dynaop.Invocation)     */    public Object intercept(Invocation invocation) throws Throwable {        return ((Interceptor)pico.getComponentInstance(key)).intercept(invocation);    }    /* (non-Javadoc)     * see org.aopalliance.intercept.MethodInterceptor#invoke(org.aopalliance.intercept.MethodInvocation)     */    public Object invoke(MethodInvocation invocation) throws Throwable {        return ((MethodInterceptor)pico.getComponentInstance(key)).invoke(invocation);    }}



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