org.directwebremoting.spring.SpringContainer 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 2005 Joe Walker
 *
 * 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.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.directwebremoting.Container;
import org.directwebremoting.extend.ContainerConfigurationException;
import org.directwebremoting.extend.UninitializingBean;
import org.directwebremoting.impl.DefaultContainer;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.util.ClassUtils;

/**
 * A Container implementation that looks up all beans from the
 * configuration specified in a Spring context.
 * It loads the configuration from a Spring web application context.
 * @author Bram Smeets
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class SpringContainer extends DefaultContainer implements Container, BeanFactoryAware, UninitializingBean
{
    /* (non-Javadoc)
     * @see org.springframework.beans.factory.BeanFactoryAware#setBeanFactory(org.springframework.beans.factory.BeanFactory)
     */
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException
    {
        this.beanFactory = beanFactory;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.impl.DefaultContainer#addParameter(java.lang.String, java.lang.Object)
     */
    @SuppressWarnings("unchecked")
    @Override
    public void addParameter(String askFor, Object valueParam) throws ContainerConfigurationException
    {
        try
        {
            Class clz = ClassUtils.forName(askFor, ClassUtils.getDefaultClassLoader());

            Map beansOfType = (Map) ((ListableBeanFactory) beanFactory).getBeansOfType(clz);

            if (beansOfType.isEmpty())
            {
                super.addParameter(askFor, valueParam);
            }
            else if (beansOfType.size() > 1)
            {
                // TODO: handle multiple declarations
                throw new ContainerConfigurationException("multiple beans of type '" + clz.getName() + "' were found in the spring configuration");
            }
            else
            {
                beans.put(askFor, beansOfType.values().iterator().next());
            }
        }
        catch (ClassNotFoundException ex)
        {
            super.addParameter(askFor, valueParam);
        }
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.impl.DefaultContainer#getBean(java.lang.String)
     */
    @Override
    public Object getBean(String id)
    {
        Object reply;
        try
        {
            reply = beanFactory.getBean(id);
        }
        catch (BeansException ex)
        {
            // Spring throws on not-found, we return null.
            reply = super.getBean(id);
        }
        catch (IllegalStateException ex)
        {
            // Spring contexts can get shutdown and throw. It's not ideal to
            // hide spring context beans, but we don't have much choice.
            return super.getBean(id);
        }

        return reply;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.impl.DefaultContainer#getBeanNames()
     */
    @Override
    public Collection getBeanNames()
    {
        List names = new ArrayList();

        // Snarf the beans from Spring
        if (beanFactory instanceof ListableBeanFactory)
        {
            try
            {
                ListableBeanFactory listable = (ListableBeanFactory) beanFactory;
                names.addAll(Arrays.asList(listable.getBeanDefinitionNames()));
            }
            catch (IllegalStateException ex)
            {
                log.warn("List of beanNames does not include Spring beans since the BeanFactory was closed when we tried to read it.");
            }
        }
        else
        {
            log.warn("List of beanNames does not include Spring beans since your BeanFactory is not a ListableBeanFactory.");
        }

        // And append the DWR ones
        names.addAll(super.getBeanNames());

        return Collections.unmodifiableCollection(names);
    }

    /**
     * Avoids initialization of lazy-init beans in Spring context.
     */
    @Override
    protected void callInitializingBeans()
    {
        callInitializingBeans(super.getBeanNames());
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.impl.DefaultContainer#destroy()
     */
    @Override
    public void destroy()
    {
        // This override prevents us from trying to poke around in the Spring
        // BeanFactory which gets Spring all confused
        // We're being destroyed, we shouldn't be touching Spring beans
        super.destroy(super.getBeanNames());
    }

    /**
     * The Spring BeanFactory that we read from
     */
    protected BeanFactory beanFactory;

    /**
     * The log stream
     */
    private static final Log log = LogFactory.getLog(SpringContainer.class);
}