Class AbstractHttpServlet

  • All Implemented Interfaces:
    ResourceConnector, Serializable, Servlet, ServletConfig
    Direct Known Subclasses:
    GroovyServlet, TemplateServlet

    public abstract class AbstractHttpServlet
    extends HttpServlet
    implements ResourceConnector
    A base class dealing with common HTTP servlet API housekeeping aspects.

    Resource name mangling (pattern replacement)

    Also implements Groovy's ResourceConnector in a dynamic manner. It allows you to modify the resource name that is searched for with a replace all operation. See Pattern and Matcher for details. The servlet init parameter names are:

     "" = empty - defaults to null = empty - defaults to null = true (default) | false means replaceFirst()
    Note: If you specify a regex, you have to specify a replacement string too! Otherwise an exception gets raised.

    Logging and bug-hunting options

    This implementation provides a verbosity flag switching log statements. The servlet init parameter name is:

     verbose = false(default) | true

    In order to support class-loading-troubles-debugging with Tomcat 4 or higher, you can log the class loader responsible for loading some classes. See GROOVY-861 for details. The servlet init parameter name is:

     log.GROOVY861 = false(default) | true

    If you experience class-loading-troubles with Tomcat 4 (or higher) or any other servlet container using custom class loader setups, you can fallback to use (slower) reflection in Groovy's MetaClass implementation. Please contact the dev team with your problem! Thanks. The servlet init parameter name is:

     reflection = false(default) | true
    See Also:
    Serialized Form
    • Field Detail


        public static final String INIT_PARAM_RESOURCE_NAME_REGEX_FLAGS
        See Also:
        Constant Field Values

        public static final String CONTENT_TYPE_TEXT_HTML
        Content type of the HTTP response.
        See Also:
        Constant Field Values

        public static final String INC_SERVLET_PATH
        Servlet API include key name: servlet_path
        See Also:
        Constant Field Values
      • servletContext

        protected ServletContext servletContext
        Servlet (or the web application) context.
      • resourceNameReplacement

        protected String resourceNameReplacement
        The replacement used by the resource name matcher.
      • resourceNameReplaceAll

        protected boolean resourceNameReplaceAll
        The replace method to use on the matcher.
         true - replaceAll(resourceNameReplacement); (default)
         false - replaceFirst(resourceNameReplacement);
      • verbose

        protected boolean verbose
        Controls almost all log output.
      • encoding

        protected String encoding
        Encoding to use, becomes charset part of contentType.
      • reflection

        protected boolean reflection
        Mirrors the static value of the reflection flag in MetaClass. See AbstractHttpServlet#logGROOVY861
    • Constructor Detail

      • AbstractHttpServlet

        public AbstractHttpServlet()
        Initializes all fields with default values.
    • Method Detail

      • generateNamePrefixOnce

        protected void generateNamePrefixOnce()
      • getScriptUri

        protected String getScriptUri​(HttpServletRequest request)
        Returns the include-aware uri of the script or template file.
        request - the http request to analyze
        the include-aware uri either parsed from request attributes or hints provided by the servlet container
      • applyResourceNameMatcher

        protected String applyResourceNameMatcher​(String uri)
      • getScriptUriAsFile

        protected File getScriptUriAsFile​(HttpServletRequest request)
        Parses the http request for the real script or template source file.
        request - the http request to analyze
        a file object using an absolute file path name, or null if the servlet container cannot translate the virtual path to a real path for any reason (such as when the content is being made available from a .war archive).
      • init

        public void init​(ServletConfig config)
                  throws ServletException
        Overrides the generic init method to set some debug flags.
        Specified by:
        init in interface Servlet
        init in class GenericServlet
        config - the servlet configuration provided by the container
        ServletException - if init() method defined in super class javax.servlet.GenericServlet throws it
      • setVariables

        protected void setVariables​(ServletBinding binding)
        Override this method to set your variables to the Groovy binding.

        All variables bound the binding are passed to the template source text, e.g. the HTML file, when the template is merged.

        The binding provided by TemplateServlet does already include some default variables. As of this writing, they are (copied from ServletBinding):

        • "request" : HttpServletRequest
        • "response" : HttpServletResponse
        • "context" : ServletContext
        • "application" : ServletContext
        • "session" : request.getSession(false)

        And via implicit hard-coded keywords:

        • "out" : response.getWriter()
        • "sout" : response.getOutputStream()
        • "html" : new MarkupBuilder(response.getWriter())

        The binding also provides convenient methods:

        • "forward(String path)" : request.getRequestDispatcher(path).forward(request, response);
        • "include(String path)" : request.getRequestDispatcher(path).include(request, response);
        • "redirect(String location)" : response.sendRedirect(location);

        Example binding all servlet context variables:

         class MyServlet extends TemplateServlet {
           protected void setVariables(ServletBinding binding) {
             // Bind a simple variable
             binding.setVariable("answer", new Long(42));
             // Bind all servlet context attributes...
             ServletContext context = (ServletContext) binding.getVariable("context");
             Enumeration enumeration = context.getAttributeNames();
             while (enumeration.hasMoreElements()) {
               String name = (String) enumeration.nextElement();
               binding.setVariable(name, context.getAttribute(name));
        binding - to be modified