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

/*
 * Copyright 2006 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.directwebremoting.spring;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import org.directwebremoting.create.NewCreator;
import org.directwebremoting.filter.ExtraLatencyAjaxFilter;
import org.directwebremoting.util.Logger;
import org.springframework.beans.FatalBeanException;
import org.springframework.beans.PropertyValue;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.beans.factory.HierarchicalBeanFactory;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionReaderUtils;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.ChildBeanDefinition;
import org.springframework.beans.factory.support.ManagedList;
import org.springframework.beans.factory.support.ManagedMap;
import org.springframework.beans.factory.xml.BeanDefinitionDecorator;
import org.springframework.beans.factory.xml.BeanDefinitionParser;
import org.springframework.beans.factory.xml.BeanDefinitionParserDelegate;
import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import org.springframework.util.xml.DomUtils;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * The Spring namespace handler which handles all elements that are defined as
 * part of the DWR namespace. <br/>
 * The DWR namespace is defined in the <code>spring-dwr-X.X.xsd</code> file. All
 * elements that are encountered in Spring configuration files are automatically
 * converted to their actual bean representation in the Spring bean registry.
 *
 * @author Erik Wiersma
 * @author Bram Smeets
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class DwrNamespaceHandler extends NamespaceHandlerSupport
{
    /* (non-Javadoc)
     * @see org.springframework.beans.factory.xml.NamespaceHandler#init()
     */
    public void init()
    {
        // register bean definition parsers and decorators for all dwr namespace elements
        registerBeanDefinitionParser("configuration", new ConfigurationBeanDefinitionParser());
        registerBeanDefinitionParser("controller", new ControllerBeanDefinitionParser());

        registerBeanDefinitionDecorator("init", new InitDefinitionDecorator());
        registerBeanDefinitionDecorator("create", new CreatorBeanDefinitionDecorator());
        registerBeanDefinitionDecorator("convert", new ConverterBeanDefinitionDecorator());
        registerBeanDefinitionDecorator("signatures", new SignaturesBeanDefinitionDecorator());
        registerBeanDefinitionDecorator("remote", new RemoteBeanDefinitionDecorator());
    }
    
    /*
     *
     */
    protected BeanDefinition registerSpringConfiguratorIfNecessary(BeanDefinitionRegistry registry)
    {
        if (!registry.containsBeanDefinition(DEFAULT_SPRING_CONFIGURATOR_ID))
        {
            BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(SpringConfigurator.class);
            builder.addPropertyValue("creators", new ManagedMap());
            builder.addPropertyValue("converters", new ManagedMap());
            registry.registerBeanDefinition(DEFAULT_SPRING_CONFIGURATOR_ID, builder.getBeanDefinition());
        }
        return registry.getBeanDefinition(DEFAULT_SPRING_CONFIGURATOR_ID);
    }

    /**
     * Registers a new {@link org.directwebremoting.extend.Creator} in the registry using name <code>javascript</code>.
     * @param registry The definition of all the Beans
     * @param javascript The name of the bean in the registry.
     * @param beanCreator The {@link org.directwebremoting.extend.Creator} to register.
     * @param children The node list to check for nested elements
     */
    protected void registerCreator(BeanDefinitionRegistry registry, String javascript, BeanDefinitionBuilder creatorConfig, Map params,  NodeList children)
    {
        registerSpringConfiguratorIfNecessary(registry);

        List includes = new ArrayList();
        creatorConfig.addPropertyValue("includes", includes);

        List excludes = new ArrayList();
        creatorConfig.addPropertyValue("excludes", excludes);

        Properties auth = new Properties();
        creatorConfig.addPropertyValue("auth", auth);

        // 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 (node.getNodeName().equals("dwr:latencyfilter"))
            {
                BeanDefinitionBuilder beanFilter = BeanDefinitionBuilder.rootBeanDefinition(ExtraLatencyAjaxFilter.class);
                beanFilter.addPropertyValue("delay", child.getAttribute("delay"));
                BeanDefinitionHolder holder2 = new BeanDefinitionHolder(beanFilter.getBeanDefinition(), "__latencyFilter_" + javascript);
                BeanDefinitionReaderUtils.registerBeanDefinition(holder2, registry);

                ManagedList filterList = new ManagedList();
                filterList.add(new RuntimeBeanReference("__latencyFilter_" + javascript));
                creatorConfig.addPropertyValue("filters", filterList);
            }
            else if (node.getNodeName().equals("dwr:include"))
            {
                includes.add(child.getAttribute("method"));
            }
            else if (node.getNodeName().equals("dwr:exclude"))
            {
                excludes.add(child.getAttribute("method"));
            }
            else if (node.getNodeName().equals("dwr:auth"))
            {
                auth.setProperty(child.getAttribute("method"), child.getAttribute("role"));
            }
            else if (node.getNodeName().equals("dwr:convert"))
            {
                Element element = (Element) node;
                String type = element.getAttribute("type");
                String className = element.getAttribute("class");

                ConverterConfig converterConfig = new ConverterConfig();
                converterConfig.setType(type);
                parseConverterSettings(converterConfig, element);
                lookupConverters(registry).put(className, converterConfig);
            }
            else if (node.getNodeName().equals("dwr:filter"))
            {
                Element element = (Element) node;
                String filterClass = element.getAttribute("class");
                BeanDefinitionBuilder beanFilter;
                try
                {
                    beanFilter = BeanDefinitionBuilder.rootBeanDefinition(ClassUtils.forName(filterClass));
                }
                catch (ClassNotFoundException e)
                {
                    throw new IllegalArgumentException("DWR filter class '" + filterClass + "' was not found. " + 
                                                       "Check the class name specified in <dwr:filter class=\"" + filterClass + 
                                                       "\" /> exists");
                }
                BeanDefinitionHolder holder2 = new BeanDefinitionHolder(beanFilter.getBeanDefinition(), "__filter_" + filterClass + "_" + javascript);
                BeanDefinitionReaderUtils.registerBeanDefinition(holder2, registry);

                ManagedList filterList = new ManagedList();
                filterList.add(new RuntimeBeanReference("__filter_" + filterClass + "_" + javascript));
                creatorConfig.addPropertyValue("filters", filterList);
            }
            else if (node.getNodeName().equals("dwr:param"))
            {
                Element element = (Element) node;
                String name = element.getAttribute("name");
                String value = element.getAttribute("value");
                params.put(name, value);
            }
            else
            {
                throw new RuntimeException("an unknown dwr:remote sub node was fouund: " + node.getNodeName());
            }
        }
        creatorConfig.addPropertyValue("params", params);
        
        String creatorConfigName = "__" + javascript;
        BeanDefinitionHolder holder3 = new BeanDefinitionHolder(creatorConfig.getBeanDefinition(), creatorConfigName);
        BeanDefinitionReaderUtils.registerBeanDefinition(holder3, registry);

        lookupCreators(registry).put(javascript, new RuntimeBeanReference(creatorConfigName));
    }

    protected class ConfigurationBeanDefinitionParser implements BeanDefinitionParser
    {
        
        public BeanDefinition parse(Element element, ParserContext parserContext)
        {
            BeanDefinitionRegistry registry = parserContext.getRegistry();
            BeanDefinition beanDefinition = registerSpringConfiguratorIfNecessary(registry);

            Element initElement = DomUtils.getChildElementByTagName(element, "init");
            if (initElement != null)
            {
                decorate(initElement, new BeanDefinitionHolder(beanDefinition, DEFAULT_SPRING_CONFIGURATOR_ID), parserContext);    
            }
            
            List createElements = DomUtils.getChildElementsByTagName(element, "create");
            Iterator iter = createElements.iterator();
            while (iter.hasNext())
            {
                Element createElement = (Element) iter.next();
                decorate(createElement, new BeanDefinitionHolder(beanDefinition, DEFAULT_SPRING_CONFIGURATOR_ID), parserContext);
            }

            List convertElements = DomUtils.getChildElementsByTagName(element, "convert");
            iter = convertElements.iterator();
            while (iter.hasNext())
            {
                Element convertElement = (Element) iter.next();
                decorate(convertElement, new BeanDefinitionHolder(beanDefinition, DEFAULT_SPRING_CONFIGURATOR_ID), parserContext);
            }
            
            List signatureElements = DomUtils.getChildElementsByTagName(element, "signatures");