org.directwebremoting.struts.StrutsCreator 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.struts;

import java.lang.reflect.Method;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.ActionForm;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.util.RequestUtils;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.extend.AbstractCreator;
import org.directwebremoting.extend.Creator;
import org.directwebremoting.util.FakeHttpServletRequestFactory;
import org.directwebremoting.util.LocalUtil;
import org.directwebremoting.util.Loggers;

/**
 * StrutsCreator
 * @author Ariel O. Falduto
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class StrutsCreator extends AbstractCreator implements Creator
{
    /**
     *
     */
    public StrutsCreator()
    {
        try
        {
            Class moduleUtilsClass = LocalUtil.classForName("org.apache.struts.util.ModuleUtils");
            getInstanceMethod = moduleUtilsClass.getMethod("getInstance");
            getModuleNameMethod = moduleUtilsClass.getMethod("getModuleName", String.class, ServletContext.class);
            getModuleConfigMethod = moduleUtilsClass.getMethod("getModuleConfig", String.class, ServletContext.class);

            Loggers.STARTUP.debug("Using Struts 1.2 based ModuleUtils code");
        }
        catch (Exception ex)
        {
            getInstanceMethod = null;
            getModuleNameMethod = null;
            getModuleConfigMethod = null;

            Loggers.STARTUP.debug("Failed to find Struts 1.2 ModuleUtils code. Falling back to 1.1 based code");
        }
    }

    /**
     * Struts formBean to be retrieved
     * @param formBean Struts bean form related.
     */
    public void setFormBean(String formBean)
    {
        this.formBean = formBean;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Creator#getType()
     */
    public Class getType()
    {
        synchronized (this)
        {
            if (moduleConfig == null)
            {
                WebContext wc = WebContextFactory.get();

                if (getInstanceMethod != null)
                {
                    try
                    {
                        // ModuleUtils utils = ModuleUtils.getInstance();
                        Object utils = getInstanceMethod.invoke(null);

                        // String moduleName = utils.getModuleName("/", wc.getServletContext());
                        String moduleName = (String) getModuleNameMethod.invoke(utils, "/", wc.getServletContext());

                        // moduleConfig = utils.getModuleConfig(moduleName, wc.getServletContext());
                        moduleConfig = (ModuleConfig) getModuleConfigMethod.invoke(utils, moduleName, wc.getServletContext());
                    }
                    catch (Exception ex)
                    {
                        throw new IllegalArgumentException(ex);
                    }
                }
                else
                {
                    HttpServletRequest request = wc.getHttpServletRequest();
                    if (request == null)
                    {
                        Loggers.STARTUP.warn("Using a FakeHttpServletRequest as part of setup");
                        request = FakeHttpServletRequestFactory.create();
                    }

                    moduleConfig = RequestUtils.getModuleConfig(request, wc.getServletContext());
                }
            }
        }

        try
        {
            return LocalUtil.classForName(moduleConfig.findFormBeanConfig(formBean).getType());
        }
        catch (ClassNotFoundException ex)
        {
            throw new IllegalArgumentException("Class not found: " + moduleConfig.findFormBeanConfig(formBean).getType(), ex);
        }
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Creator#getInstance()
     */
    public Object getInstance() throws InstantiationException
    {
        // fills for the first time the moduleConfig
        ActionForm formInstance = (ActionForm) WebContextFactory.get().getSession().getAttribute(formBean);
        if (formInstance == null)
        {
            throw new InstantiationException("Can't find formInstance  for " + formBean);
        }

        return formInstance;
    }

    /**
     * The FormBean that we lookup to call methods on
     */
    private String formBean = null;

    /**
     * moduleConfig allows us to do the lookup
     */
    private ModuleConfig moduleConfig = null;

    /**
     * Reflection access to 1.2 code for compatibility with 1.1
     */
    private Method getInstanceMethod;

    /**
     * Reflection access to 1.2 code for compatibility with 1.1
     */
    private Method getModuleNameMethod;

    /**
     * Reflection access to 1.2 code for compatibility with 1.1
     */
    private Method getModuleConfigMethod;
}