org.directwebremoting.guice.DwrGuiceServletModule 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 2007 Tim Peierls
 *
 * 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.guice;

import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.directwebremoting.ScriptSession;
import org.directwebremoting.ServerContext;
import org.directwebremoting.ServerContextFactory;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;

import com.google.inject.Provider;
import com.google.inject.TypeLiteral;

import static org.directwebremoting.guice.DwrGuiceUtil.*;
import static org.directwebremoting.guice.DwrScopes.*;

/**
 * Configures DWR scopes and creates bindings for commonly
 * used objects related to those scopes: request, response,
 * script session, session, servlet context, and web context.
 * 
 * Since Guice's ServletModule makes its own bindings for requests,
 * responses, and sessions, this class has a constructor that lets
 * the user specify whether to avoid conflicts by not binding these types.
 * 
 * @author Tim Peierls [tim at peierls dot net]
 */
class DwrGuiceServletModule extends AbstractDwrModule
{
    /**
     * Creates a module to configure DWR scopes and bindings;
     * might produce conflicts with the bindings provided by
     * Guice's ServletModule if {@code bindPotentiallyConflictingTypes}
     * is true. In addition, this module always binds the potentially
     * conflicting types (ServletRequest, ServletResponse, HttpSession,
     * HttpServletRequest, and HttpServetResponse) with a distinguishing
     * {@link Dwr @Dwr} annotation.
     */
    DwrGuiceServletModule(boolean bindPotentiallyConflictingTypes)
    {
        this.bindPotentiallyConflictingTypes = bindPotentiallyConflictingTypes;
    }


    @Override
    protected void configure()
    {
        bindScope(RequestScoped.class, REQUEST);
        bindScope(SessionScoped.class, SESSION);
        bindScope(ScriptSessionScoped.class, SCRIPT);
        bindScope(ApplicationScoped.class, APPLICATION);
        bindScope(GlobalApplicationScoped.class, GLOBAL);

        if (bindPotentiallyConflictingTypes)
        {
            bind(ServletRequest.class)
                .toProvider(requestProvider);
            bind(HttpServletRequest.class)
                .toProvider(requestProvider);
            bind(ServletResponse.class)
                .toProvider(responseProvider);
            bind(HttpServletResponse.class)
                .toProvider(responseProvider);
            bind(HttpSession.class)
                .toProvider(sessionProvider);
            bind(ServletContext.class)
                .toProvider(servletContextProvider);
        }

        bind(ServletRequest.class)
            .annotatedWith(Dwr.class)
            .toProvider(requestProvider);
        bind(HttpServletRequest.class)
            .annotatedWith(Dwr.class)
            .toProvider(requestProvider);
        bind(ServletResponse.class)
            .annotatedWith(Dwr.class)
            .toProvider(responseProvider);
        bind(HttpServletResponse.class)
            .annotatedWith(Dwr.class)
            .toProvider(responseProvider);
        bind(HttpSession.class)
            .annotatedWith(Dwr.class)
            .toProvider(sessionProvider);
        bind(ServletContext.class)
            .annotatedWith(Dwr.class)
            .toProvider(servletContextProvider);

        bind(new TypeLiteral>() {})
            .annotatedWith(RequestParameters.class)
            .toProvider(requestParametersProvider);

        bind(ScriptSession.class)
            .toProvider(scriptSessionProvider);
        bind(WebContext.class)
            .toProvider(webContextProvider);
        bind(ServerContext.class)
            .toProvider(serverContextProvider);
    }


    private final Provider requestProvider = new Provider()
    {
        public HttpServletRequest get()
        {
            WebContext webcx = WebContextFactory.get();
            return webcx.getHttpServletRequest();
        }

        @Override
        public String toString()
        {
            return "RequestProvider";
        }
    };

    private final Provider responseProvider = new Provider()
    {
        public HttpServletResponse get()
        {
            WebContext webcx = WebContextFactory.get();
            return webcx.getHttpServletResponse();
        }

        @Override
        public String toString()
        {
            return "ResponseProvider";
        }
    };

    private final Provider sessionProvider = new Provider()
    {
        public HttpSession get()
        {
            WebContext webcx = WebContextFactory.get();
            return webcx.getSession();
        }

        @Override
        public String toString()
        {
            return "SessionProvider";
        }
    };

    private final Provider> requestParametersProvider = new Provider>()
    {
        @SuppressWarnings({"unchecked"})
        public Map get()
        {
            WebContext webcx = WebContextFactory.get();
            return webcx.getHttpServletRequest().getParameterMap();
        }

        @Override
        public String toString()
        {
            return "RequestParametersProvider";
        }
    };

    private final Provider scriptSessionProvider = new Provider()
    {
        public ScriptSession get()
        {
            WebContext webcx = WebContextFactory.get();
            return webcx.getScriptSession();
        }

        @Override
        public String toString()
        {
            return "ScriptSessionProvider";
        }
    };

    private final Provider servletContextProvider = new Provider()
    {
        public ServletContext get()
        {
            // Can work even if WebContext isn't found.
            return getServletContext();
        }

        @Override
        public String toString()
        {
            return "ServletContextProvider";
        }
    };

    private final Provider webContextProvider = new Provider()
    {
        public WebContext get()
        {
            return WebContextFactory.get();
        }

        @Override
        public String toString()
        {
            return "WebContextProvider";
        }
    };

    private final Provider serverContextProvider = new Provider()
    {
        public ServerContext get()
        {
            return ServerContextFactory.get();
        }

        @Override
        public String toString()
        {
            return "ServerContextProvider";
        }
    };
}