groovy.servlet
[Java] Class AbstractHttpServlet

java.lang.Object
  javax.servlet.http.HttpServlet
      groovy.servlet.AbstractHttpServlet

All Implemented Interfaces:

ResourceConnector

public abstract class AbstractHttpServlet
extends HttpServlet

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:

 resource.name.regex = empty - defaults to null
 resource.name.replacement = empty - defaults to null
 resource.name.replace.all = true (default) | false means replaceFirst()
 

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
 

Authors:

Christian Stein

Roshan Dawrani (roshandawrani)

CONTENT_TYPE_TEXT_HTML

public static final String CONTENT_TYPE_TEXT_HTML

Content type of the HTTP response.

INC_PATH_INFO

public static final String INC_PATH_INFO

Servlet API include key name: path_info

INC_REQUEST_URI

public static final String INC_REQUEST_URI

INC_SERVLET_PATH

public static final String INC_SERVLET_PATH

Servlet API include key name: servlet_path

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

resourceNameMatcher

protected Matcher resourceNameMatcher

Either null or a compiled pattern matcher read from "resource.name.regex" and used in AbstractHttpServlet#getScriptUri(HttpServletRequest)#getScriptUri(HttpServletRequest).

resourceNameReplaceAll

protected boolean resourceNameReplaceAll

The replace method to use on the matcher.

 true - replaceAll(resourceNameReplacement); (default)
 false - replaceFirst(resourceNameReplacement);
 

resourceNameReplacement

protected String resourceNameReplacement

The replacement used by the resource name matcher.

servletContext

protected ServletContext servletContext

Servlet (or the web application) context.

verbose

protected boolean verbose

Controls almost all log output.

AbstractHttpServlet

public AbstractHttpServlet()

Initializes all fields with default values.

getResourceConnection

public URLConnection getResourceConnection(String name)

Interface method for ResourceContainer. This is used by the GroovyScriptEngine.

getScriptUri

protected String getScriptUri(HttpServletRequest request)

Returns the include-aware uri of the script or template file.

Parameters:

request - the http request to analyze

Returns:

the include-aware uri either parsed from request attributes or hints provided by the servlet container

getScriptUriAsFile

protected File getScriptUriAsFile(HttpServletRequest request)

Overrides the generic init method to set some debug flags.

throws:

ServletException if init() method defined in super class javax.servlet.GenericServlet throws it

Parameters:

config - the servlet configuration provided by the container

init

public void init(ServletConfig config)

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));
     }
   }
 }
 

Parameters:

binding - to be modified