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 fall back 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:
  • Field Details


      public static final String INIT_PARAM_RESOURCE_NAME_REGEX
      See Also:

      public static final String INIT_PARAM_RESOURCE_NAME_REGEX_FLAGS
      See Also:

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

      public static final String INC_PATH_INFO
      Servlet API include key name: path_info
      See Also:

      public static final String INC_REQUEST_URI
      See Also:

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

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

      protected Pattern resourceNamePattern
      Either null or a compiled pattern read from """" and used in getScriptUri(HttpServletRequest).
    • 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
    • namePrefix

      protected String namePrefix
      a.fink: it was in removeNamePrefix(java.lang.String), but was extracted to var for optimization
  • Constructor Details

    • AbstractHttpServlet

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

    • generateNamePrefixOnce

      protected void generateNamePrefixOnce()
    • removeNamePrefix

      protected String removeNamePrefix(String name) throws ResourceException
    • getResourceConnection

      public URLConnection getResourceConnection(String name) throws ResourceException
      Interface method for ResourceContainer. This is used by the GroovyScriptEngine.
      Specified by:
      getResourceConnection in interface ResourceConnector
    • 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