Package org.apache.turbine.pipeline
Interface Valve
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- All Known Implementing Classes:
CleanUpValve
,DefaultACLCreationValve
,DefaultLoginValve
,DefaultSessionTimeoutValve
,DefaultSessionValidationValve
,DefaultSetEncodingValve
,DetermineActionValve
,DetermineRedirectRequestedValve
,DetermineTargetValve
,ExecutePageValve
,URLMapperValve
- Functional Interface:
- This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public interface Valve
A Valve is a request processing component. A series of Valves are generally associated with each other into a Pipeline. The detailed contract for a Valve is included in the description of the
HISTORICAL NOTE: The "Valve" name was assigned to this concept because a valve is what you use in a real world pipeline to control and/or modify flows through it.invoke()
method below.- Author:
- Craig R. McClanahan, Gunnar Rjnning, Peter Donald, Daniel Rall
- See Also:
invoke(PipelineData, ValveContext)
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Method Summary
All Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description default void
initialize()
Initialize the valve before using in a pipeline.void
invoke(PipelineData pipelineData, ValveContext context)
Perform request processing as required by this Valve.
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Method Detail
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invoke
void invoke(PipelineData pipelineData, ValveContext context) throws IOException, TurbineException
Perform request processing as required by this Valve.
An individual Valve MAY perform the following actions, in the specified order:
- Examine and/or modify the properties of the specified Request and Response.
- Examine the properties of the specified Request, completely generate the corresponding Response, and return control to the caller.
- Examine the properties of the specified Request and Response, wrap either or both of these objects to supplement their functionality, and pass them on.
- If the corresponding Response was not generated (and control was not
returned, call the next Valve in the pipeline (if there is one) by
executing
context.invokeNext()
. - Examine, but not modify, the properties of the resulting Response
(which was created by a subsequently invoked Valve via a
call to
context.invokeNext()
).
A Valve MUST NOT do any of the following things:
- Change request properties that have already been used to direct the flow of processing control for this request.
- Create a completed Response AND pass this Request and Response on to the next Valve in the pipeline.
- Consume bytes from the input stream associated with the Request, unless it is completely generating the response, or wrapping the request before passing it on.
- Modify the HTTP headers included with the Response after the
invokeNext()
method has returned. - Perform any actions on the output stream associated with the
specified Response after the
invokeNext()
method has returned.
- Parameters:
pipelineData
- The run-time information, including the servlet request and response we are processing.context
- The valve context used to invoke the next valve in the current processing pipeline- Throws:
IOException
- Thrown by a subsequent Valve.TurbineException
- Thrown by a subsequent Valve.
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initialize
default void initialize() throws Exception
Initialize the valve before using in a pipeline.- Throws:
Exception
- if initialization fails
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