| org.apache.cocoon.components.flow.Interpreter
All known Subclasses: org.apache.cocoon.components.flow.AbstractInterpreter,
| Interpreter | | public interface Interpreter (Code) | | The interface to the flow scripting languages. This interface is
for a component, which implements the appropriate language to be
used for describing the flow. A system could have multiple
components that implement this interface, each of them for a
different scripting language.
A flow script defines what is the page flow in an interactive
Web application. Usually the flow is defined in a high level
programming language which provides the notion of continuations,
which allows for the flow of the application to be described as a
simple procedural program, without having to think about the
application as a finite state machine which changes its internal
state on each HTTP request from the client browser.
However an implementation may choose to use its own
representation of an application, which may include XML
representations of finite state machines. Note: this API has no
provision for such implementations.
The component represented by this interface is called in three
situations:
-
From the sitemap, to invoke a top level function defined in a
given implementation language of the flow. This is done from
the * sitemap using the construction:
<map:call function="..." language="..."/>
The language attribute can be ignored if the *
default language is used.
-
From the sitemap, to continue a previously started
computation. A previously started computation is saved in the
form of a continuation inside the flow implementation language.
This case is similar with the above one, but the function
invoked has a special name, specific to each language
implementation. See the language implementation for more
information on the function name and the arguments it receives.
-
From a program in the flow layer. This is done to invoke a
pipeline defined in the sitemap, to generate the response of the
request.
author:
Ovidiu Predescu
since:
March 11, 2002
version:
CVS $Id: Interpreter.java 433543 2006-08-22 06:22:54Z crossley $ |
| Inner Class :public static class Argument | |
| callFunction | | void callFunction(String funName, List params, Redirector redirector) throws Exception(Code) | | This method is called from the sitemap, using the syntax
<map:call function="..."/>
The method will execute the named function, which must be defined
in the given language. There is no assumption made on how various
arguments are passed to the function.
The params argument is a List object
that contains Interpreter.Argument instances,
representing the parameters to be passed to the called
function. An Argument instance is a key-value pair,
where the key is the name of the parameter, and the value is its
desired value. Most languages will ignore the name value and
simply pass to the function, in a positional order, the values of
the argument. Some languages however can pass the arguments in a
different order than the original prototype of the function. For
these languages the ability to associate the actual argument with
a formal parameter using its name is essential.
A particular language implementation may decide to put the
environment, request, response etc. objects in the dynamic scope
available to the function at the time of the call. Other
implementations may decide to pass these as arguments to the
called function.
The current implementation assumes the sitemap implementation
is TreeProcessor.
Parameters:
funName - a String value, the name of thefunction to call
Parameters:
params - a List object whose components areCallFunctionNode.Argument instances. The interpretation of theparameters is left to the actual implementation of theinterpreter.
Parameters:
redirector - a Redirector used to call views |
| forwardTo | | void forwardTo(String uri, Object bizData, WebContinuation continuation, Redirector redirector) throws Exception(Code) | | Forward the request to a Cocoon pipeline.
Parameters:
uri - a String, the URI of the forwarded request
Parameters:
bizData - an Object, the business data objectto be made available to the forwarded pipeline
Parameters:
continuation - a WebContinuation, thecontinuation to be called to resume the processing
Parameters:
redirector - a Redirector used to call views
exception:
Exception - if an error occurs |
| getInterpreterID | | String getInterpreterID()(Code) | | the unique ID for this interpreter. |
| handleContinuation | | void handleContinuation(String continuationId, List params, Redirector redirector) throws Exception(Code) | | Continues a previously started processing. The continuation
object where the processing should start from is indicated by the
continuationId string.
Parameters:
continuationId - a String value
Parameters:
params - a List value, containing theparameters to be passed when invoking the continuation. Asopposed to the parameters passed by callFunction,these parameters will only become available in the language'senvironment, if at all.
Parameters:
redirector - a Redirector used to call views
exception:
Exception - if an error occurs |
| setInterpreterID | | void setInterpreterID(String interpreterID)(Code) | | Set the unique ID for this interpreter.
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