org.directwebremoting.impl.DefaultWebContext 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.impl;

import java.io.IOException;
import java.io.StringWriter;

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

import org.directwebremoting.Container;
import org.directwebremoting.ScriptSession;
import org.directwebremoting.extend.RealScriptSession;
import org.directwebremoting.extend.RealWebContext;
import org.directwebremoting.util.SwallowingHttpServletResponse;

/**
 * A default implementation of WebContext.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class DefaultWebContext extends DefaultServerContext implements RealWebContext
{
    /**
     * Create a new DefaultWebContext
     * @param container The IoC container
     * @param request The incoming http request
     * @param response The outgoing http reply
     * @param servletConfig The servlet configuration
     * @param servletContext The servlet context
     * @see org.directwebremoting.WebContextFactory.WebContextBuilder#engageThread(Container, HttpServletRequest, HttpServletResponse)
     */
    protected DefaultWebContext(Container container, HttpServletRequest request, HttpServletResponse response, ServletConfig servletConfig, ServletContext servletContext)
    {
        setServletConfig(servletConfig);
        setServletContext(servletContext);
        setContainer(container);

        this.request = request;
        this.response = response;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.extend.RealWebContext#initialize(java.lang.String, org.directwebremoting.extend.RealScriptSession)
     */
    public void initialize(final String sentPage, RealScriptSession scriptSession)
    {
        this.scriptSession = scriptSession;
        this.page = sentPage;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.WebContext#getCurrentPage()
     */
    public String getCurrentPage()
    {
        if (page == null)
        {
            throw new UnsupportedOperationException("CurrentPage is not supported from a JSON call.");
        }

        return page;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.WebContext#getScriptSession()
     */
    public ScriptSession getScriptSession()
    {
        return scriptSession;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.WebContext#getSession()
     */
    public HttpSession getSession()
    {
        return request.getSession();
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.WebContext#getSession(boolean)
     */
    public HttpSession getSession(boolean create)
    {
        return request.getSession(create);
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.WebContext#getHttpServletRequest()
     */
    public HttpServletRequest getHttpServletRequest()
    {
        return request;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.WebContext#getHttpServletResponse()
     */
    public HttpServletResponse getHttpServletResponse()
    {
        return response;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.WebContext#forwardToString(java.lang.String)
     */
    public String forwardToString(String url) throws ServletException, IOException
    {
        StringWriter sout = new StringWriter();
        StringBuffer buffer = sout.getBuffer();

        HttpServletResponse realResponse = getHttpServletResponse();
        HttpServletResponse fakeResponse = new SwallowingHttpServletResponse(realResponse, sout, realResponse.getCharacterEncoding());

        HttpServletRequest realRequest = getHttpServletRequest();
        realRequest.setAttribute(ATTRIBUTE_DWR, Boolean.TRUE);

        getServletContext().getRequestDispatcher(url).include(realRequest, fakeResponse);

        return buffer.toString();
    }

    /**
     * ScriptSession IDs are too long to be useful to humans. We shorten them
     * to the first 4 characters.
     */
    private String simplifyId(String id)
    {
        if (id == null)
        {
            return "[null]";
        }

        if (id.length() == 0)
        {
            return "[blank]";
        }

        if (id.length() < 4)
        {
            return id;
        }

        return id.substring(0, 4);
    }

    /* (non-Javadoc)
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString()
    {
        return "DefaultWebContext[id=" + simplifyId(scriptSession.getId()) + ", page=" + page + "]";
    }

    /**
     * The unique ID (like a session ID) assigned to the current page
     */
    private RealScriptSession scriptSession;

    /**
     * The URL of the current page
     */
    private String page;

    /**
     * The HttpServletRequest associated with the current request
     */
    private final HttpServletRequest request;

    /**
     * The HttpServletResponse associated with the current request
     */
    private final HttpServletResponse response;
}