ProjectionDFA Class Reference

Represents the DFA used for stream preprojection. More...

#include <projectiondfa.h>

Collaboration diagram for ProjectionDFA:

[legend]

List of all members.

Public Member Functions
	ProjectionDFA (ProjectionTree *_pt, PassiveProjectionTree *_ppt)
	Constructor.
virtual	~ProjectionDFA ()
void	print (OutputStream &dos)
	Debug prints the projection DFA to.
ProjectionDFAState *	getInitialState ()
	Returns the initial (starting) state of the projection DFA.
Private Attributes
ProjectionDFAState *	initial
	The initial (starting) state of the projection DFA.

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Detailed Description

Represents the DFA used for stream preprojection.

The information from the statical analysis phase are compiled into this (lazily constructed) DFA. The DFA then can be used to determine whether tokens must be loaded into the buffer or can be projected away when successively processing the input stream/file.

Author:

Michael Schmidt

Gunnar Jehl

Version:

2.1

License:

Software License Agreement (BSD License)

Definition at line 53 of file projectiondfa.h.

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Constructor & Destructor Documentation

ProjectionDFA::ProjectionDFA	(	ProjectionTree *	_pt,
		PassiveProjectionTree *	_ppt
	)

Constructor.

Constructor - creating object using the ProjectionTree object that has been computed in the statical analysis phase. Note that the ProjectionDFA is computed lazily while projecting the input stream, in order to avoid unnecessary computations (the projection DFA may be unlimited in size and therefore cannot even be computed in advance)

Parameters:

[in]	_pt	The ProjectionTree object that contains information on required paths as well as role information.
[in]	_ppt	The PassiveProjectionTree object that contains required paths.

Definition at line 37 of file projectiondfa.cpp.

ProjectionDFA::~ProjectionDFA

(

)

[virtual]

Destructor.

Definition at line 41 of file projectiondfa.cpp.

References initial.

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Member Function Documentation

ProjectionDFAState * ProjectionDFA::getInitialState

(

)

[inline]

Returns the initial (starting) state of the projection DFA.

Returns the initial (starting) state of the projection DFA, i.e. the state corresponfing to thevirtual XML document root.

Return values:

ProjectioDFAState*

The starting state of the projection DFA.

Definition at line 92 of file projectiondfa.h.

References initial.

Referenced by Buffer::Buffer().

void ProjectionDFA::print

(

OutputStream &

dos

)

Debug prints the projection DFA to.

Note that only those parts of the projection DFA will be output that have been computed so far. This means that the shape of the ProjectionDFA does not only depend on the input query, but also on the current state in reading the input document and the input document itself.

Parameters:

[in]

dos

Reference to the (debug) OutputStream.

Return values:

void

Definition at line 45 of file projectiondfa.cpp.

References initial, and ProjectionDFAState::print().

Referenced by Executor::finalDebugPrint(), and Executor::initProjectionDFA().

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Member Data Documentation

ProjectionDFAState * ProjectionDFA::initial [private]

The initial (starting) state of the projection DFA.

This state corresponds to the (virtual) document root of the XML document.

Definition at line 100 of file projectiondfa.h.

Referenced by getInitialState(), print(), and ~ProjectionDFA().