dwrnamespacehandler.java

反向的AJAX。最大的特性是我们成为反向的Ajax。DWR1.x允许你用javascript异步的访问java代码。DWR2.0在这上允许你建立异步java访问javascript代码。 反向的Aj

            for (Iterator i = signatureElements.iterator(); i.hasNext();)
            {
                Element signatureElement = (Element) i.next();
                decorate(signatureElement, new BeanDefinitionHolder(beanDefinition, DEFAULT_SPRING_CONFIGURATOR_ID), parserContext);
            }

            return beanDefinition;
        }
    }

    protected class ControllerBeanDefinitionParser implements BeanDefinitionParser
    {
        public BeanDefinition parse(Element element, ParserContext parserContext)
        {
            BeanDefinitionBuilder dwrController = BeanDefinitionBuilder.rootBeanDefinition(DwrController.class);
            List configurators = new ManagedList();
            configurators.add(new RuntimeBeanReference(DEFAULT_SPRING_CONFIGURATOR_ID));
            dwrController.addPropertyValue("configurators", configurators);

            String debug = element.getAttribute("debug");
            if (StringUtils.hasText(debug))
            {
                dwrController.addPropertyValue("debug", debug);
            }

            String beanName = element.getAttribute(BeanDefinitionParserDelegate.ID_ATTRIBUTE);
            String nameAttr = element.getAttribute(BeanDefinitionParserDelegate.NAME_ATTRIBUTE);
            String[] aliases = null;
            if (!StringUtils.hasText(beanName))
            {
                beanName = element.getAttribute("name");
            }
            else
            {
                String aliasName = element.getAttribute("name");
                if (StringUtils.hasText(aliasName))
                {
                    aliases = StringUtils.tokenizeToStringArray(nameAttr, BeanDefinitionParserDelegate.BEAN_NAME_DELIMITERS);
                }
            }

            parseControllerParameters(dwrController, element);
            
            BeanDefinitionHolder holder = new BeanDefinitionHolder(dwrController.getBeanDefinition(), beanName, aliases);
            BeanDefinitionReaderUtils.registerBeanDefinition(holder, parserContext.getRegistry());

            return dwrController.getBeanDefinition();
        }
        
        protected void parseControllerParameters(BeanDefinitionBuilder dwrControllerDefinition, Element parent)
        {
            NodeList children = parent.getChildNodes();
            Map params = new HashMap();
            for (int i = 0; i < children.getLength(); i++)
            {
                Node node = children.item(i);

                if (node.getNodeType() == Node.TEXT_NODE || node.getNodeType() == Node.COMMENT_NODE)
                {
                    continue;
                }

                Element child = (Element) node;
                if (child.getNodeName().equals("dwr:config-param"))
                {
                    String paramName = child.getAttribute("name");
                    String value = child.getAttribute("value");
                    params.put(paramName, value);
                }
                else
                {
                    throw new RuntimeException("an unknown dwr:controller sub node was found: " + node.getNodeName());
                }
            }
            dwrControllerDefinition.addPropertyValue("configParams", params);
        }
    }

    protected class RemoteBeanDefinitionDecorator implements BeanDefinitionDecorator
    {
        /**
         * Registers an &lt;dwr:remote ... /&gt; element.
         */
        public BeanDefinitionHolder decorate(Node node, BeanDefinitionHolder definition, ParserContext parserContext)
        {
            Element element = (Element) node;

            String javascript = element.getAttribute("javascript");

            BeanDefinitionBuilder beanCreator = BeanDefinitionBuilder.rootBeanDefinition(BeanCreator.class);

            try
            {
                String beanClassName = resolveBeanClassname(definition.getBeanDefinition(), parserContext.getRegistry());
                if (beanClassName == null) 
                {
                    throw new FatalBeanException("Unabled to find type for beanName '" + definition.getBeanName() + 
                                                 "'. " + "Check your bean has a correctly configured parent or provide a class for " + 
                                                 " the bean definition");
                }
                beanCreator.addPropertyValue("beanClass", ClassUtils.forName(beanClassName));
            }
            catch (ClassNotFoundException e)
            {
                throw new FatalBeanException("Unable to create DWR bean creator for '" + definition.getBeanName() + "'.", e);
            }

            String name = definition.getBeanName();
            if (name.startsWith("scopedTarget."))
            {
                name = name.substring(name.indexOf(".") + 1);
            }
            beanCreator.addPropertyValue("beanId", name);
            beanCreator.addPropertyValue("javascript", javascript);

            BeanDefinitionBuilder creatorConfig = BeanDefinitionBuilder.rootBeanDefinition(CreatorConfig.class);
            creatorConfig.addPropertyValue("creator", beanCreator.getBeanDefinition());            
            registerCreator(parserContext.getRegistry(), javascript, creatorConfig, new HashMap(), node.getChildNodes());

            return definition;
        }
        
        /**
         *  Try getting the beanClassName from the definition and if that fails try to get it from 
         *  the parent (and even parent BeanFactory if we have to).
         *  
         *  @param definition 
         *  @param registry
         *  @return class name or null if not found
         */
        private String resolveBeanClassname(BeanDefinition definition, BeanDefinitionRegistry registry) 
        {
            String beanClassName = definition.getBeanClassName();    
            if (!StringUtils.hasText(beanClassName)) 
            {
                while (definition instanceof ChildBeanDefinition )
                {
                    String parentName = ((ChildBeanDefinition)definition).getParentName();                    
                    BeanDefinition parentDefinition = findParentDefinition(parentName, registry);
                    if (parentDefinition == null)
                    {
                        if (log.isDebugEnabled()) 
                        {
                            log.debug("No parent bean named '" + parentName + "' could be found in the " + 
                                      "hierarchy of BeanFactorys. Check you've defined a bean called '" + parentName + "'");
                        }
                        break;
                    }
                    beanClassName = parentDefinition.getBeanClassName();
                    if (StringUtils.hasText(beanClassName ))
                    {
                        // found the class name we were looking for
                        break;
                    }
                    definition = parentDefinition;
                }
            }
           
            return beanClassName;
        }
        
        private BeanDefinition findParentDefinition(String parentName, BeanDefinitionRegistry registry)
        {   
            if (registry != null) 
            {
                if (registry.containsBeanDefinition(parentName)) 
                {
                    return registry.getBeanDefinition(parentName);
                } 
                else if (registry instanceof HierarchicalBeanFactory) 
                {
                    // Try to get parent definition from the parent BeanFactory. This could return null
                    BeanFactory parentBeanFactory = ((HierarchicalBeanFactory)registry).getParentBeanFactory();
                    return findParentDefinition(parentName, (BeanDefinitionRegistry)parentBeanFactory);
                } 
            }
            
            // we've exhausted all possibilities        
            return null;
        }
    }

    protected class ConverterBeanDefinitionDecorator implements BeanDefinitionDecorator
    {

        public BeanDefinitionHolder decorate(Node node, BeanDefinitionHolder definition, ParserContext parserContext)
        {
            Element element = (Element) node;
            String type = element.getAttribute("type");
            String className = element.getAttribute("class");
            String javascriptClassName = element.getAttribute("javascript");
            
            BeanDefinitionRegistry registry = parserContext.getRegistry();

            ConverterConfig converterConfig = new ConverterConfig();
            converterConfig.setType(type);
            converterConfig.setJavascriptClassName(javascriptClassName);
            parseConverterSettings(converterConfig, element);
            lookupConverters(registry).put(className, converterConfig);

            return definition;
        }
    }

    protected void parseConverterSettings(ConverterConfig converterConfig, Element parent)
    {
        NodeList children = parent.getChildNodes();

        // check to see if there are any nested elements here
        for (int i = 0; i < children.getLength(); i++)
        {
            Node node = children.item(i);

            if (node.getNodeType() == Node.TEXT_NODE || node.getNodeType() == Node.COMMENT_NODE)
            {
                continue;
            }

            Element child = (Element) node;
            if (child.getNodeName().equals("dwr:include"))
            {
                converterConfig.addInclude(child.getAttribute("method"));
            }
            else if (child.getNodeName().equals("dwr:exclude"))
            {
                converterConfig.addExclude(child.getAttribute("method"));
            }
            /* TODO Why is this only a property of ObjectConverter?
             else if (child.getNodeName().equals("dwr:force"))
             {
             converterConfig.setForce(Boolean.parseBoolean(child.getAttribute("value")));
             }
             */
            else
            {
                throw new RuntimeException("an unknown dwr:remote sub node was found: " + node.getNodeName());
            }