[Java] Class AbstractHttpServlet
- groovy.servlet.AbstractHttpServlet
- All Implemented Interfaces and Traits:
- 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:
{
- value:
- #INIT_PARAM_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
Field Summary
Modifiers | Name | Description |
---|---|---|
static String | CONTENT_TYPE_TEXT_HTML | Content type of the HTTP response. |
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 |
static String | INIT_PARAM_RESOURCE_NAME_REGEX | |
static String | INIT_PARAM_RESOURCE_NAME_REGEX_FLAGS | |
protected String | encoding | Encoding to use, becomes charset part of contentType. |
protected String | namePrefix | a.fink: it was in removeNamePrefix, but was extracted to var for optimization |
protected boolean | reflection | Mirrors the static value of the reflection flag in MetaClass. |
protected Pattern | resourceNamePattern | Either null or a compiled pattern read from "{@value #INIT_PARAM_RESOURCE_NAME_REGEX}" and used in AbstractHttpServlet.getScriptUri. |
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
Constructor and description |
---|
AbstractHttpServlet
() Initializes all fields with default values. |
Methods Summary
Type Params | Return Type | Name and description |
---|---|---|
protected String |
applyResourceNameMatcher(String uri) | |
protected void |
generateNamePrefixOnce() | |
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 String |
removeNamePrefix(String name) | |
protected void |
setVariables(ServletBinding binding) Override this method to set your variables to the Groovy binding. |
Field Detail
public static final String CONTENT_TYPE_TEXT_HTML
Content type of the HTTP response.
public static final String INC_PATH_INFO
Servlet API include key name: path_info
public static final String INC_REQUEST_URI
public static final String INC_SERVLET_PATH
Servlet API include key name: servlet_path
public static final String INIT_PARAM_RESOURCE_NAME_REGEX
public static final String INIT_PARAM_RESOURCE_NAME_REGEX_FLAGS
protected String encoding
Encoding to use, becomes charset part of contentType.
protected String namePrefix
a.fink: it was in removeNamePrefix, but was extracted to var for optimization
protected boolean reflection
Mirrors the static value of the reflection flag in MetaClass. See AbstractHttpServlet#logGROOVY861
protected Pattern resourceNamePattern
Either null
or a compiled pattern read from "{
- value:
- #INIT_PARAM_RESOURCE_NAME_REGEX}" and used in AbstractHttpServlet.getScriptUri.
protected boolean resourceNameReplaceAll
The replace method to use on the matcher.
true - replaceAll(resourceNameReplacement); (default) false - replaceFirst(resourceNameReplacement);
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 Detail
public AbstractHttpServlet()
Initializes all fields with default values.
Method Detail
protected String applyResourceNameMatcher(String uri)
protected void generateNamePrefixOnce()
public URLConnection getResourceConnection(String name)
Interface method for ResourceContainer. This is used by the GroovyScriptEngine.
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
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).
public void init(ServletConfig config)
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
protected String removeNamePrefix(String name)
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
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Licensed under the Apache license.
https://docs.groovy-lang.org/2.5.14/html/gapi/groovy/servlet/AbstractHttpServlet.html