ServletBinding (groovy 2.2.0 API)

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Groovy 2.2.0

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groovy.servlet
[Java] Class ServletBinding

java.lang.Object
  groovy.lang.GroovyObjectSupport
      groovy.lang.Binding
          groovy.servlet.ServletBinding

public class ServletBinding
extends Binding

Servlet-specific binding extension to lazy load the writer or the output stream from the response.

Eager variables

"request" : the HttpServletRequest object
"response" : the HttpServletRequest object
"context" : the ServletContext object
"application" : same as context
"session" : shorthand for request.getSession(false) - can be null!
"params" : map of all form parameters - can be empty
"headers" : map of all request header fields

Lazy variables

"out" : response.getWriter()
"sout" : response.getOutputStream()
"html" : new MarkupBuilder(response.getWriter()) - expandEmptyElements flag is set to true
"json" : new JsonBuilder()

As per the Servlet specification, a call to response.getWriter() should not be done if a call to response.getOutputStream() has already occurred or the other way around. You may wonder then how the above lazy variables can possibly be provided - since setting them up would involve calling both of the above methods. The trick is catered for behind the scenes using lazy variables. Lazy bound variables can be requested without side effects; under the covers the writer and stream are wrapped. That means response.getWriter() is never directly called until some output is done using 'out' or 'html'. Once a write method call is done using either of these variable, then an attempt to write using 'sout' will cause an IllegalStateException. Similarly, if a write method call on 'sout' has been done already, then any further write method call on 'out' or 'html' will cause an IllegalStateException.

Reserved internal variable names (see "Methods" below)

"forward"
"include"
"redirect"

If response.getWriter() is called directly (without using out), then a write method call on 'sout' will not cause the IllegalStateException, but it will still be invalid. It is the responsibility of the user of this class, to not to mix these different usage styles. The same applies to calling response.getOutputStream() and using 'out' or 'html'.

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)

Authors:: Guillaume Laforge; Christian Stein; Jochen Theodorou

Method Summary
`def`	`ServletBinding(HttpServletRequest request, HttpServletResponse response, ServletContext context)` Initializes a servlet binding.
`void`	`forward(String path)`
`Object`	`getVariable(String name)` @return a writer, an output stream, a markup builder or another requested object
`Map`	`getVariables()`
`void`	`include(String path)`
`void`	`redirect(String location)`
`void`	`setVariable(String name, Object value)`

Methods inherited from class Binding
getProperty, getVariable, getVariables, hasVariable, setProperty, setVariable

Methods inherited from class GroovyObjectSupport
getMetaClass, getProperty, invokeMethod, setMetaClass, setProperty

Methods inherited from class Object
wait, wait, wait, equals, toString, hashCode, getClass, notify, notifyAll

Method Detail

ServletBinding

public def ServletBinding(HttpServletRequest request, HttpServletResponse response, ServletContext context)

Initializes a servlet binding.

Parameters:: request - the HttpServletRequest object; response - the HttpServletRequest object; context - the ServletContext object

forward

public void forward(String path)

getVariable

@Override
public Object getVariable(String name)

Returns:: a writer, an output stream, a markup builder or another requested object

getVariables

@Override
public Map getVariables()

include

public void include(String path)

redirect

public void redirect(String location)

setVariable

@Override
public void setVariable(String name, Object value)

groovy.servlet [Java] Class ServletBinding