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/*
 * The contents of this file are subject to the terms 
 * of the Common Development and Distribution License 
 * (the License).  You may not use this file except in
 * compliance with the License.
 * 
 * You can obtain a copy of the license at 
 * https://jsftemplating.dev.java.net/cddl1.html or
 * jsftemplating/cddl1.txt.
 * See the License for the specific language governing 
 * permissions and limitations under the License.
 * 
 * When distributing Covered Code, include this CDDL 
 * Header Notice in each file and include the License file 
 * at jsftemplating/cddl1.txt.  
 * If applicable, add the following below the CDDL Header, 
 * with the fields enclosed by brackets [] replaced by
 * you own identifying information: 
 * "Portions Copyrighted [year] [name of copyright owner]"
 * 
 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
 */
package com.sun.jsftemplating.util.fileStreamer;

import com.sun.jsftemplating.util.LogUtil;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.StringTokenizer;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/**
 *  	This Servlet provides the ability to stream information
 *	from the server to the client.  It provides the ability to set the
 *	Content-type of the streamed content, if not specified, it will attempt
 *	to guess based on the extension (if possible).  It requires the
 *	{@link ContentSource} of the data to stream to be specified by
 *	passing in a ServletRequest parameter named
 *	{@link ServletStreamerContext#CONTENT_SOURCE_ID}.  The
 *	{@link ContentSource} provides a plugable way of obtaining data from
 *	any source (i.e. the filesystem, generated data, from the network, a
 *	database, etc.).  The available {@link ContentSource} implemenatations
 *	must be specified via a Servlet init parameter named
 *	{@link Context#CONTENT_SOURCES}.
 */
public class ServletStreamer extends HttpServlet {

    /**
     *	 Default Constructor.
     */
    public ServletStreamer() {
	super();
    }

    /**
     *	 Servlet initialization method.
     */
    public void init(ServletConfig config) throws ServletException {
	super.init(config);

	// Register ContentSources
	String sources = config.getInitParameter(Context.CONTENT_SOURCES);
	if ((sources != null) && (sources.trim().length() != 0)) {
	    FileStreamer fs = FileStreamer.getFileStreamer(config.getServletContext());
	    StringTokenizer tokens = new StringTokenizer(sources, " \t\n\r\f,;:");
	    while (tokens.hasMoreTokens()) {
		fs.registerContentSource(tokens.nextToken());
	    }
	}
    }

    /**
     *	 This method delegates to the {@link #doPost(
     *	    HttpServletRequest, HttpServletResponse)} method.
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	doPost(request, response);
    }

    /**
     *	 This method is the main method for this class when used in an
     *	    HttpServlet environment.  It starts the process, by
     *	    creating a {@link ServletStreamerContext} and invoking
     *	    {@link FileStreamer#streamContent(Context)}.
     *
     *	 The {@link Context#FILE_PATH} will be set to the PATH_INFO of the
     *	    HttpServletRequest.
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	// Get the ServletStreamerContext
	Context context = getServletStreamerContext(request, response);

	// Stream Content
	try {
	    FileStreamer.getFileStreamer(getServletContext()).streamContent(context);
	} catch (FileNotFoundException ex) {
	    if (LogUtil.infoEnabled()) {
		LogUtil.info("JSFT0004", (Object) request.getPathInfo());
	    }
	    response.sendError(HttpServletResponse.SC_NOT_FOUND);
	} catch (IOException ex) {
	    if (LogUtil.infoEnabled()) {
		String path = request.getPathInfo();
		LogUtil.info("JSFT0004", (Object) path);
		if (LogUtil.fineEnabled()) {
		    LogUtil.fine(
			"Resource (" + path + ") not available!", ex);
		}
	    }
// FIXME: send 404?
	}
    }

    /**
     *	 This method instantiates a {@link ServletStreamerContext} and
     *	    initializes it with the ServletConfig,
     *	    HttpServletRequest, and
     *	    HttpServletResponse.
     *
     *	@param	request	    The HttpServletRequest.
     *	@param	response    The HttpServletResponse.
     */
    protected ServletStreamerContext getServletStreamerContext(HttpServletRequest request, HttpServletResponse response) {
	ServletStreamerContext ctx = (ServletStreamerContext)
	    request.getAttribute(SERVLET_STREAMER_CONTEXT);
	if (ctx == null) {
	    ctx = new ServletStreamerContext(
		    request, response, getServletConfig());
	    request.setAttribute(SERVLET_STREAMER_CONTEXT, ctx);
	}

	// This is every time b/c the response may initially be null,
	// subsequent calls may provide this a non-null value.
	ctx.setServletResponse(response);

	return ctx;
    }

    /**
     *	 HttpServlet defines this method.  This method gets
     *	    called before the doGet / doPost methods.  This requires us to
     *	    create the {@link Context} here.  However, we do not have the
     *	    HttpServletResponse yet, so we will pass in
     *	    null.
     */
    @Override
    protected long getLastModified(HttpServletRequest request) {
	// Get the ServletStreamerContext
	Context context = getServletStreamerContext(request, null);

	// Get the ContentSource
	ContentSource source = context.getContentSource();
	
	// Calculate the last modified date
	return source.getLastModified(context);
    }


    /**
     *	 This String ("servletStreamerContext") is the name if the
     *	    ServletRequest attribute used to store the
     *	    {@link Context} object for this request.
     */
    public static final String SERVLET_STREAMER_CONTEXT	    = "servletStreamerContext";

    /**
     *	 The Default Content-type ("application/octet-stream").
     */
    public static final String DEFAULT_CONTENT_TYPE =
	    "application/octet-stream";
}