groovy.servlet

Class AbstractHttpServlet

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

groovy.servlet.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:

 resource.name.regex = empty - defaults to null
 resource.name.replacement = empty - defaults to null
 resource.name.replace.all = 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
 

Author:

Christian Stein, Roshan Dawrani (roshandawrani)

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	CONTENT_TYPE_TEXT_HTML Content type of the HTTP response.
protected String	encoding Encoding to use, becomes charset part of contentType.
static String	INC_PATH_INFO Servlet API include key name: path_info
static String	INC_REQUEST_URI
static String	INC_SERVLET_PATH Servlet API include key name: servlet_path
protected boolean	reflection Mirrors the static value of the reflection flag in MetaClass.
protected Matcher	resourceNameMatcher Either null or a compiled pattern matcher read from "resource.name.regex" and used in getScriptUri(HttpServletRequest).
protected boolean	resourceNameReplaceAll The replace method to use on the matcher.
protected String	resourceNameReplacement The replacement used by the resource name matcher.
protected ServletContext	servletContext Servlet (or the web application) context.
protected boolean	verbose Controls almost all log output.

Constructor Summary

Constructors

Constructor and Description
AbstractHttpServlet() Initializes all fields with default values.

Method Summary

Methods

Modifier and Type	Method and Description
URLConnection	getResourceConnection(String name) Interface method for ResourceContainer.
protected String	getScriptUri(HttpServletRequest request) Returns the include-aware uri of the script or template file.
protected File	getScriptUriAsFile(HttpServletRequest request) Parses the http request for the real script or template source file.
void	init(ServletConfig config) Overrides the generic init method to set some debug flags.
protected void	setVariables(ServletBinding binding) Override this method to set your variables to the Groovy binding.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CONTENT_TYPE_TEXT_HTML

public static final String CONTENT_TYPE_TEXT_HTML

Content type of the HTTP response.

See Also:

Constant Field Values

INC_PATH_INFO

public static final String INC_PATH_INFO

Servlet API include key name: path_info

See Also:

Constant Field Values

INC_REQUEST_URI

public static final String INC_REQUEST_URI

See Also:

Constant Field Values

INC_SERVLET_PATH

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.

resourceNameMatcher

protected Matcher resourceNameMatcher

Either null or a compiled pattern matcher read from "resource.name.regex" 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

Constructor Detail

AbstractHttpServlet

public AbstractHttpServlet()

Initializes all fields with default values.

Method Detail

getResourceConnection

public URLConnection getResourceConnection(String name)
                                    throws ResourceException

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

Specified by:

getResourceConnection in interface ResourceConnector

Throws:

ResourceException

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)

Parses the http request for the real script or template source file.

Parameters:

request - the http request to analyze

Returns:

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

Overrides:

init in class GenericServlet

Parameters:

config - the servlet configuration provided by the container

Throws:

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));
     }
   }
 }
 

Parameters:

binding - to be modified