bes
Updated for version 3.17.0
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Entry point into BES, building responses to given requests. More...
#include <BESInterface.h>
Public Member Functions | |
virtual void | dump (ostream &strm) const |
dumps information about this object More... | |
virtual int | execute_request (const string &from) |
virtual int | finish_with_error (int status) |
Static Public Member Functions | |
static void | add_end_callback (p_bes_end end) |
static void | add_init_callback (p_bes_init init) |
Protected Member Functions | |
BESInterface (ostream *strm) | |
virtual void | build_data_request_plan ()=0 |
Build the data request plan. More... | |
virtual void | clean () |
Clean up after the request. | |
virtual void | end_request () |
End the BES request. More... | |
virtual int | exception_manager (BESError &e) |
Manage any exceptions thrown during the whole process. More... | |
virtual void | execute_data_request_plan () |
Execute the data request plan. More... | |
virtual int | finish (int status) |
virtual void | initialize () |
Initialize the BES object. More... | |
virtual void | invoke_aggregation () |
Aggregate the resulting response object. | |
virtual void | log_status () |
Log the status of the request. | |
virtual void | report_request () |
Report the request and status of the request to BESReporterList::TheList() More... | |
virtual void | transmit_data () |
Transmit the resulting response object. More... | |
virtual void | validate_data_request () |
Validate the incoming request information. | |
Protected Attributes | |
BESDataHandlerInterface * | _dhi |
BESTransmitter * | _transmitter |
BESInterface is an abstract class providing the entry point into the retrieval of information using the BES framework. There are eight steps to retrieving a response to a given request:
The way in which the response is generated is as follows. A BESResponseHandler is found that knows how to build the requested response object. The built-in response handlers are for the response objects das, dds, ddx, data, help, version. These response handlers are added to a response handler list during initialization. Additional response handlers can be added to this list. For example, in Cedar, response handlers are registered to build flat, tab, info, and stream responses.
To build the response objects a user can make many requests. For example, a das object can be built using as many different files as is requested, say for file1,file2,file3,file4. And each of these files could be of a different data type. For example, file1 and file3 could be cedar files, file2 could be cdf file and file4 could be a netcdf file.
The structure that holds all of the requested information is the BESDataHandlerInterface. It holds on to a list of containers, each of which has the data type (cedar, cdf, nph, etc...) and the file to be read. The BESDataHandlerInterface is built in the build request method.
The response handlers know how to build the specified response object, such as DAS, DDS, help, status, version, etc...
For each container in the BESDataHandlerInterface find the request handler (BESRequestHandler) for the containers data type. Each request handler registers functions that know how to fill in a certain type of response (DAS, DDS, etc...). Find that function and invoke it. So, for example, there is a CedarRequestHandler class that registers functions that knows how to fill in the different response objects from cedar files.
Once the response object is filled it is transmitted using a specified BESTransmitter.
The status is then logged (default is to not log any status. It is up to derived classes of BESInterface to implement the log_status method.)
The request and status are then reported. The default action is to pass off the reporting to BESReporterList::TheList(), which has a list of registered reporters and passes off the information to each of those reporters. For example, if the Cedar project wants to report on any cedar access then it can register a reporter with BESReporterList::TheList().
Definition at line 123 of file BESInterface.h.
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protectedpure virtual |
It is the responsibility of the derived class to build the request plan. In other words, the container list must be filled in and the action set in the BESDataHandlerInterface structure.
Implemented in BESBasicInterface, and BESXMLInterface.
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virtual |
Displays the pointer value of this instance along with information about BESDataHandlerInterface, the BESTransmitter being used, and the number of initialization and termination callbacks.
strm | C++ i/o stream to dump the information to |
Implements BESObj.
Reimplemented in BESBasicInterface, and BESXMLInterface.
Definition at line 740 of file BESInterface.cc.
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protectedvirtual |
This method allows developers to add callbacks at the end of a request, to do any cleanup or do any extra work at the end of a request
Definition at line 687 of file BESInterface.cc.
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protectedvirtual |
Specific responses are generated given a specific Exception caught. If additional exceptions are thrown within derived systems then implement those in the derived exception_manager methods. This is a catch-all manager and should be called once derived methods have caught their exceptions.
e | BESError to be managed |
Definition at line 727 of file BESInterface.cc.
References BESExceptionManager::handle_exception().
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protectedvirtual |
Given the information in the BESDataHandlerInterface, execute the request. To do this we simply find the response handler given the action in the BESDataHandlerInterface and tell it to execute.
If no BESResponseHandler can be found given the action then an exception is thrown.
Reimplemented in BESBasicInterface, and BESXMLInterface.
Definition at line 525 of file BESInterface.cc.
References BESResponseHandler::execute(), BESContextManager::get_context(), and BESStopWatch::start().
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protectedvirtual |
This method must be called by all derived classes as it will initialize the environment
Reimplemented in BESBasicInterface, and BESXMLInterface.
Definition at line 479 of file BESInterface.cc.
References BESStopWatch::start().
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protectedvirtual |
If interested in reporting the request and status of the request then one must register a BESReporter with BESReporterList::TheList().
If no BESReporter objects are registered then nothing happens.
Reimplemented in BESXMLInterface.
Definition at line 668 of file BESInterface.cc.
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protectedvirtual |
The derived classes are responsible for specifying a transmitter object for use in transmitting the response object. Again, the BESResponseHandler knows how to transmit itself.
If no response handler or no response object or no transmitter is specified then do nothing here.
Reimplemented in BESBasicInterface, and BESXMLInterface.
Definition at line 608 of file BESInterface.cc.
References BESStopWatch::start().