When Framework is Overkill

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When Framework is Overkill

Dapeng Liu

Feb. 03, 09 · Java Zone ·

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Recently there have been some hot articles about frameworks: Better Java Web Frameworks and Better Java Web Frameworks: ItsNat. Sometimes I've found that frameworks just make life harder. Recently I was assigned a job to create a company's site from scratch. The requirement is relatively simple, less than 10 static HTML pages, literally no server side processing.

I decided to write a simple mini "framework" to aid my client's designer, instead of adpoting an off-the-shelf web framework.

The idea is pretty much the same as most CMS: to keep a big template out and to only let the user (the maintanence designer) touch the content of the page. Yet, I want to provide flexibility to some degree. For example, at least I wanted to do some simple SEO to every page.

Template:

<html>
<head>
	<title>{{title}}</title>
	<meta name="description" content="{{description}}" />
</head>
<body>
	<div id="head">
		... ignored for simplicity... 
	</div>
	<div id="content">{{body}}</div>
	<div id="footer">... </div>
</body>
</html>

And with the template, the actual page needs only to provide the information like TITLE, BODY, DESCRIPTION:

e.g., "about-us.html":

{{title}} About Us
{{description}} what ever information that you want search engine know

{{body}} ... here is the real content, ignored for simplicity...

So I need a ServletFilter to intercept the request and to wrap the response from "about-us.html" and to make any necessary subsititutions. I search the default servlet's output for anything like {{ABC}} and use "String.replace" to try to replace/insert into the template string. Once all is done, I dump the result to the original response.

I have included my source code below. The BufferedServletOutputStream class is copy-and-pasted from a Google search result, sorry I couldn't find the author's name:

public class StaticSiteTemplate implements Filter {
    private Map defaultParameters = new HashMap();
    private String template = "";

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        ...
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        CapturedHttpResponseWrapper wrapper = new CapturedHttpResponseWrapper((HttpServletResponse) response);
        chain.doFilter(request, wrapper);
// find tagString originalContent = wrapper.toString();
        Pattern pattern = Pattern.compile( < a
        href = "file://%7b//%7B//w+//%7D//%7D"
        mce_href = "file://%7b//%7B//w+//%7D//%7D" >\\{\\{\\w +\\}\\}</a >);
        Matcher matcher = pattern.matcher(originalContent);
        String result = template;
        if (matcher.find()) {
            ArrayList breakpointList = new ArrayList();
            breakpointList.add(new TemplateBreakupPoint(matcher.group(), matcher.end(), originalContent.length()));
            while (matcher.find()) {
                breakpointList.get(breakpointList.size() - 1).end = matcher.start();
                breakpointList.add(new TemplateBreakupPoint(matcher.group(), matcher.end(), originalContent.length()));
            }
            for (TemplateBreakupPoint tbp : breakpointList) {
                result = result.replace(tbp.key, originalContent.substring(tbp.start, tbp.end).trim());
            }
        } else {// assume all belong to bodyresult = template.replace("{{body}}", originalContent);}
// replace default params
            for (String key : defaultParameters.keySet()) {
                result = result.replace(key, defaultParameters.get(key));
            }
// dump outputbyte[] buffer = result.getBytes(response.getCharacterEncoding());
            response.setContentLength(buffer.length);
            response.getOutputStream().write(buffer);
        }

    public void loadTemplate() throws IOException {...}

    ...
}