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BrEventIOclass description - source file - inheritance tree class BrEventIO : public BrIOModule
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Data Members
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Class DescriptionBrEventIO Class to write/read BrEvent data on/from a ROOT TFile. The class is derived from the BrIOModule class, so that it conforms to the regular BrModule interface. Description: ------------ This class is meant to simplify writing BRAHMS output in ROOT format. The user simply creates the object which has defaults that work. Several options are also provided in case they are needed. Usage (recommended): ------------------- The recommended way of using the class is like using any other BrModule: Create an object and add it to some module container (BrModuleContainer), for example the BrMainModule container singleton. 1 to any number of files to can be specified (See BrIOModule::AddFile). If more than one file is added to the module, one should set the BrIOModule::kBrRunFile flag in the file IO mode (see BrIOModule::SetIOMode). If only one file is opened by the module, then the BrIOModule::kBrJobFile flag should be set. Here's and example using the BrMainModule container object mainModule: BrEventIO* inputModule = new BrEventIO("input", ""); inputModule->SetIOMode(BrIOModule::kBrJobFile|BrIOModule::kBrWriteFile); inputModule->AddFile("foo.root"); mainModule->AddModule(inputModule); ... other modules follow BrEventIO* outputModule = new BrEventIO("output", ""); outputModule->SetIOMode(BrIOModule::kBrJobFile|BrIOModule::kBrWriteFile); outputModule->AddFile("bar.root"); mainModule->AddModule(outputModule); Usage (depreciated): ------------------- The old, and depreciated, way of using this class, is to create an object (BrEventIO::BrEventIO), open the file (BrEventIO::Open) and then use the BrEventIO::Event(BrEvent* event) method for event by event writing of event objects. Finally, the file must be closed using BrEventIO::Close. The file can be opened either in READ mode for readonly operations or in RECREATE mode for write operations. The TFile APPEND option is not currently supported. The default file mode is a ROOT tree. The mode can be manually selected using the SetFileMode(option) method. Example: BrEventIO *io = new BrEventIO("input"); if (!input->Open("foo.root","READ")) return; ... More modules while (kTRUE) { BrEvent* inEvent = new BrEvent("ev,0,0); BrEvent* outEvent = new BrEvent("ev,0,0); input->Event(inEvent); if (input->IsError()) return; if (input->IsEof()) return; ... More follows here delete inEvent; delete outEvent; } input->Close(); BrEventIO() : fTopLevel(kTRUE) Default constructor BrEventIO(const Char_t *name, const Char_t* title) : BrIOModule(BREVENTIO_NAME, name), fTopLevel(kTRUE) Constructor. name becomes Name and Title for the Module. No data file is opened this has to be done in the Open() method. Option can by "READ" "RECREATE" ~BrEventIO() Destructor for BrEventIO. Close the file if open. Delete the TFile object Bool_t Open(const Char_t *fname,const Option_t *option) Open the file with fname. Returns kFALSE if the file can't be opened. Otherwise the fFileName data member is set to the corresponding filepointer. Options: READ for readonly mode or RECREATE for write mode. RECREATE mode: If option is RECREATE, a new file is created. This object is written out to indicate the file mode (Tree or Serial). If file mode is to be different than the default (Tree), the SetFileMode(mode) needs to be used before the Open method. READ mode: if option is READ, existing file is opened. This object is read in to get information on file mode. Bool_t InitializeRootSerialFile() Routine to Initialize ROOT serial file This routine does nothing if in write mode. If in read mode, a list of Keys is found from the event file and stored in fListOfKeys. The file header key is removed from the list of keys void SetTreeParameters(Int_t bufSize, Int_t split) Set the TTree parameters buffer size and split level. For the exact meaning of these, please refer to the TTree class description, and the ROOT Users Guide, chapter 12 [1]. The default values should do fine for most applications. /* References: Bool_t InitializeRootTreeFile() Routine to initialize ROOT tree file (default writing mode) if file opened in write mode: Create the tree Initialize some counters Set up a single branch with fSplit=1. Setting branches by hand is not yet supported. if file opened in read mode. Get the tree object from the file Set counter of the number of entries in the file Initialize some counters and flags Bool_t Close() Close the file Opened by the object. Return kFALSE if no file was open. Bool_t SkipEvent(Int_t numevt) Skip events on input only void Event(BrEvent* event) Reads or writes one event depending on whether we are in read mode or write mode void ProcessRootSerialFile(BrEvent *event) Do Serial File specific actions to read or write the file depending on mode if write mode, simply write the object and increment number of events written. if read mode, get the next key, Create a dummy event using key->ReadObj(); Copy the dummy event into the event we are passing back. increment number of events read void ProcessRootTreeFile(BrEvent *event) Do Tree File specific actions to read or write the file depending on mode if Write mode, set the branch address to the event argument, then fTree->Fill(); if Read mode, set branch address to event argument, then fTree->GetEvent(fEventNumber); void SetFileMode(BrFileTag::EFileMode mode) Set file mode. mode can be either BrFileTag::kTree or BrFileTag::kSerial mode must be set before opening the file. void Browse(TBrowser* b) void Print(Option_t* option) const Print information on this module Options: Z Print file tag T Print tree info (TTree::Print) F Print file info (TFile::Print) See also BrIOModule::Print. Inline Functions
BrFileTag::EFileMode GetFileMode() const
TFile* GetROOTFile()
Bool_t IsFolder() const
TClass* Class()
TClass* IsA() const
void ShowMembers(TMemberInspector& insp, char* parent)
void Streamer(TBuffer& b)
void StreamerNVirtual(TBuffer& b)
BrEventIO BrEventIO(BrEventIO&)
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Copyright ; 2002 BRAHMS Collaboration
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