org.directwebremoting.spring.namespace.ConfigurationParser Maven / Gradle / Ivy

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DWR is easy Ajax for Java. It makes it simple to call Java code directly from Javascript. It gets rid of almost all the boiler plate code between the web browser and your Java code.
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/*
 * Copyright 2010 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.namespace;

import java.util.List;

import org.directwebremoting.spring.SpringConfigurator;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.ManagedList;
import org.springframework.beans.factory.support.ManagedMap;
import org.springframework.beans.factory.xml.BeanDefinitionParser;
import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.util.Assert;
import org.springframework.util.xml.DomUtils;
import org.w3c.dom.Element;

/**
 * Parses a <dwr:configuration> tag and all its children.
 *
 * @author Jose Noheda [[email protected]]
 */
public final class ConfigurationParser implements BeanDefinitionParser
{

    /**
     * Provided bean name for the configuration tag.
     */
    public static final String DEFAULT_SPRING_CONFIGURATOR_ID = "__dwrConfiguration";

    private final NamespaceHandlerSupport handler;

    /**
     * Configures the namespace handler for this context.
     *
     * @param handler a non null instance
     */
    public ConfigurationParser(NamespaceHandlerSupport handler) {
        Assert.notNull(handler);
        this.handler = handler;
    }

    /**
     * Registers the configuration object and recursively processes children.
     */
    public BeanDefinition parse(Element configurationElement, ParserContext parserContext)
    {
        BeanDefinitionRegistry registry = parserContext.getRegistry();
        BeanDefinition configuration = registerConfigurationIfNecessary(registry);
        parseConfigurationChildren(configurationElement, configuration, parserContext);
        return configuration;
    }

    /**
     * Checks if a configuration object (usually from a <dwr:configuration> tag) has already
     * been processed. If not it registers one automatically.
     *
     * @param registry a non null instance
     * @return the configuration bean definition currently in the context (cannot be null)
     */
    public static BeanDefinition registerConfigurationIfNecessary(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());
            builder.addPropertyValue("filters", new ManagedList());
            registry.registerBeanDefinition(DEFAULT_SPRING_CONFIGURATOR_ID, builder.getBeanDefinition());
        }
        return registry.getBeanDefinition(DEFAULT_SPRING_CONFIGURATOR_ID);
    }

    private void parseConfigurationChildren(Element configurationElement, BeanDefinition configuration, ParserContext parserContext)
    {
        parseInit(configurationElement, configuration, parserContext);
        parseFilters(configurationElement, configuration, parserContext);
        parseSignatures(configurationElement, configuration, parserContext);
        parseConverters(configurationElement, configuration, parserContext);
    }

    private void parseInit(Element configurationElement, BeanDefinition configuration, ParserContext parserContext)
    {
        Element initElement = DomUtils.getChildElementByTagName(configurationElement, "init");
        if (initElement != null)
        {
            handler.decorate(initElement, new BeanDefinitionHolder(configuration, DEFAULT_SPRING_CONFIGURATOR_ID), parserContext);
        }
    }

    @SuppressWarnings("unchecked")
    private void parseFilters(Element configurationElement, BeanDefinition configuration, ParserContext parserContext)
    {
        List filterElements = DomUtils.getChildElementsByTagName(configurationElement, "filter");
        for (Element filterElement : filterElements)
        {
            handler.decorate(filterElement, new BeanDefinitionHolder(configuration, DEFAULT_SPRING_CONFIGURATOR_ID), parserContext);
        }
    }

    @SuppressWarnings("unchecked")
    private void parseSignatures(Element configurationElement, BeanDefinition configuration, ParserContext parserContext)
    {
        List signatureElements = DomUtils.getChildElementsByTagName(configurationElement, "signatures");
        for (Element signatureElement : signatureElements)
        {
            handler.decorate(signatureElement, new BeanDefinitionHolder(configuration, DEFAULT_SPRING_CONFIGURATOR_ID), parserContext);
        }
    }

    @SuppressWarnings("unchecked")
    private void parseConverters(Element configurationElement, BeanDefinition configuration, ParserContext parserContext)
    {
        List convertElements = DomUtils.getChildElementsByTagName(configurationElement, "convert");
        for (Element convertElement : convertElements)
        {
            handler.decorate(convertElement, new BeanDefinitionHolder(configuration, DEFAULT_SPRING_CONFIGURATOR_ID), parserContext);
        }
    }

}