Package groovy.servlet
Class ServletBinding
java.lang.Object
groovy.lang.GroovyObjectSupport
groovy.lang.Binding
groovy.servlet.ServletBinding
- All Implemented Interfaces:
GroovyObject
Servlet-specific binding extension to lazy load the writer or the output
stream from the response.
Eager variables
- "request" : the
HttpServletRequestobject - "response" : the
HttpServletRequestobject - "context" : the
ServletContextobject - "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())-expandEmptyElementsflag is set to true - "json" :
new JsonBuilder()
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"
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 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)
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Constructor Summary
ConstructorsConstructorDescriptionServletBinding(HttpServletRequest request, HttpServletResponse response, ServletContext context) Initializes a servlet binding. -
Method Summary
Modifier and TypeMethodDescriptionvoidgetVariable(String name) voidvoidvoidsetVariable(String name, Object value) Sets the value of the given variableMethods inherited from class groovy.lang.Binding
getProperty, hasVariable, removeVariable, setPropertyMethods inherited from class groovy.lang.GroovyObjectSupport
getMetaClass, setMetaClassMethods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods inherited from interface groovy.lang.GroovyObject
invokeMethod
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Constructor Details
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ServletBinding
public ServletBinding(HttpServletRequest request, HttpServletResponse response, ServletContext context) Initializes a servlet binding.- Parameters:
request- the HttpServletRequest objectresponse- the HttpServletRequest objectcontext- the ServletContext object
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Method Details
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setVariable
Description copied from class:BindingSets the value of the given variable- Overrides:
setVariablein classBinding- Parameters:
name- the name of the variable to setvalue- the new value for the given variable
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getVariables
- Overrides:
getVariablesin classBinding
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getVariable
- Overrides:
getVariablein classBinding- Parameters:
name- the name of the variable to lookup- Returns:
- a writer, an output stream, a markup builder or another requested object
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forward
- Throws:
ServletExceptionIOException
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include
- Throws:
ServletExceptionIOException
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redirect
- Throws:
IOException
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