org.directwebremoting.WebContextFactory Maven / Gradle / Ivy

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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;

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

/**
 * Accessor for the current WebContext.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class WebContextFactory
{
    /**
     * Accessor for the current WebContext.
     * @return The current WebContext or null if the current thread was not
     * started by DWR.
     */
    public static WebContext get()
    {
        if (builder == null)
        {
            return null;
        }

        return builder.get();
    }

    /**
     * Internal method to allow us to get the WebContextBuilder from which we
     * will get WebContext objects.
     * Do not call this method from outside of DWR.
     * @param builder The factory object (from DwrServlet)
     */
    public static void setWebContextBuilder(WebContextBuilder builder)
    {
        WebContextFactory.builder = builder;
    }

    /**
     * The WebContextBuilder from which we will get WebContext objects
     */
    private static WebContextBuilder builder;

    /**
     * Class to enable us to access servlet parameters.
     */
    public interface WebContextBuilder
    {
        /**
         * Make the current thread know what the current request is.
         * This method is only for use internally to DWR.
         * @param request The incoming http request
         * @param response The outgoing http reply
         * @param config The servlet configuration
         * @param context The servlet context
         * @param container The IoC container
         * @see #unset()
         */
        void set(HttpServletRequest request, HttpServletResponse response, ServletConfig config, ServletContext context, Container container);

        /**
         * @return The WebContext that is associated with this thread
         */
        WebContext get();

        /**
         * Unset the current ExecutionContext
         * This method is only for use internally to DWR.
         * @see #set(HttpServletRequest, HttpServletResponse, ServletConfig, ServletContext, Container)
         */
        void unset();
    }
}