SequenceExpression Class Reference

Represents a sequence of XQuery expressions. More...

#include <sequenceexpression.h>

Inheritance diagram for SequenceExpression:

Collaboration diagram for SequenceExpression:

List of all members.

Public Member Functions

SequenceExpression (Expression *_left, Expression *_right)

Constructor.

virtual ~SequenceExpression ()

virtual void scopeCheck (vector< unsigned > &def_vars, vector< unsigned > &introduced_vars, vector< unsigned > &violating_vars)

virtual void replaceVarId (unsigned old_id, unsigned new_id)

virtual void mergeSequences ()

virtual void extractFSAMap (FSAMap *fsamap, unsigned parent_var)

virtual void extractParVarMap (ParVarMap *parvarmap)

virtual void extractDependencies (vector< DependencySet * > *depset)

virtual Expression * placeSignOffs (vector< SignOffExpression * > &signoffs)

virtual void rewriteWhereExps ()

virtual void rewriteEmptyFuncts ()

virtual void rewriteVarstepCondExps ()

virtual void rewriteAggregateFuncts ()

virtual void rewriteVarsteps ()

virtual void print (OutputStream &dos) const

virtual void init (BufferNode *root)

virtual void eval (OutputStream &eos, Environment *env, unsigned modus)

void insertExp (Expression *exp)

Inserts a new expression to this sequence of XQuery expressions.

void unsetRecursiveDelete ()

Resets recursive delete of this object.

virtual bool containsDirectOutput ()

Private Member Functions

vector< Expression * > * getExps ()

Returns the sequence of XQuery expressions.

Private Attributes

vector< Expression * > exps

The entered (sequence of) XQuery expressions.

bool delete_recursively

Indicator to change delete behaviour when the destructor is called.

Detailed Description

Represents a sequence of XQuery expressions.

Represents a sequence of XQuery expressions, which takes therefore (two) Expression, e.g. $x, $y or //book, fn:count($x), as arguments and returns the strictly sequentially evaluated results of the (two) Expression, i.e. outputs or returns the corresponding Expression values according to their (input) order.

Author:: Michael Schmidt
Gunnar Jehl

Version:: 2.1

License:: Software License Agreement (BSD License)

Definition at line 55 of file sequenceexpression.h.

Constructor & Destructor Documentation

SequenceExpression::SequenceExpression	(	Expression *	_left,
		Expression *	_right
	)

Constructor.

Constructor - creating object for two Expression.

Parameters:

`[in]`	_left	Pointer to a Expression object.
`[in]`	_right	Pointer to a Expression object.

Definition at line 37 of file sequenceexpression.cpp.

References exps.

SequenceExpression::~SequenceExpression ( ) [virtual]

Destructor.

Definition at line 43 of file sequenceexpression.cpp.

References delete_recursively, and exps.

Member Function Documentation

bool SequenceExpression::containsDirectOutput ( ) [virtual]

Returns if the corresponding expression produces direct output.

Returns if the corresponding expression produces direct output. Direct output is meant that this subexpression produces output such as node constructs or strings.

Return values:

bool true if the corresponding expression produces direct output, false otherwise.

Reimplemented from Expression.

Definition at line 212 of file sequenceexpression.cpp.

References exps, and Expression::getType().

void SequenceExpression::eval	(	OutputStream &	eos,
		Environment *	env,
		unsigned	modus
	)			`[virtual]`

Evaluates the expression in the given environment.

Evaluates the expression in the given environment. The evaluation takes place in the environment that is passed to this method. In addition, the parameter modus is one of the following: EVAL_QUERY, EVAL_QUERY_SILENT or EVAL_SIGNOFF (see also the corresponding defines for more information). This method implements the XQuery semantics for the standard expression types, but also the GCX specific extensions like signOff-statements.

Parameters:

`[in]`	eos	Pointer to a OutputStream object.
`[in]`	env	Pointer to an Environment object.
`[in]`	modus	The query evaluation mode.

Exceptions:

RuntimeException

If illegal evaluation mode.

Reimplemented from Expression.

Definition at line 193 of file sequenceexpression.cpp.

References EVAL_QUERY, EVAL_SIGNOFF, and exps.

void SequenceExpression::extractDependencies ( vector< DependencySet * > * depset ) [virtual]

Extracts the needed dependencies of a query.

Extracts the needed dependencies of a query, which are needed for constructing the ProjectionTree.

Parameters:

[in,out] depset Pointer to a vector containing Pointer to DependencySet objects.

Return values:

void

Reimplemented from Expression.

Definition at line 100 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::extractFSAMap	(	FSAMap *	fsamap,
		unsigned	parent_var
	)			`[virtual]`

Extracts the needed first straight ancestor (FSA) variables map.

Extracts the needed first straight ancestor (FSA) variables map, which is needed for correct insertion of SignOffExpression.

Parameters:

`[in,out]`	fsamap	Pointer to a FSAMap object.
`[in]`	parent_var	Parent variable.

Return values:

void

Reimplemented from Expression.

Definition at line 88 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::extractParVarMap ( ParVarMap * parvarmap ) [virtual]

Extracts the needed parent variable (ParVar) map.

Extracts the needed parent variable (ParVar) map, which is needed for constructing the VariableTree.

Parameters:

[in,out] parvarmap Pointer to a ParVarMap object.

Return values:

void

Reimplemented from Expression.

Definition at line 94 of file sequenceexpression.cpp.

References exps.

vector< Expression * > * SequenceExpression::getExps ( ) [inline, private]

Returns the sequence of XQuery expressions.

Returns the sequence of XQuery expressions, i.e. returns the member variable.

Return values:

vector<Expression*>*

Pointer to a vector object containing Pointer to Expression objects.

Definition at line 176 of file sequenceexpression.h.

References exps.

Referenced by mergeSequences().

void SequenceExpression::init ( BufferNode * root ) [virtual]

Initializes the query for evaluation.

Initializes the query for evaluation. Up to now only all required BufferIterator objects are created to speed up query evaluation.

Parameters:

[in] root Pointer to a BufferNode object.

Return values:

void

Reimplemented from Expression.

Definition at line 187 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::insertExp ( Expression * exp ) [inline]

Inserts a new expression to this sequence of XQuery expressions.

Parameters:

[in] exp Pointer to a Expression object.

Return values:

void

Definition at line 153 of file sequenceexpression.h.

References exps.

void SequenceExpression::mergeSequences ( ) [virtual]

Merges belonging together XQuery sequences into a single sequence.

Merges belonging together XQuery sequences into a single sequence, which is done because of better/nicer output look.

Return values:

void

Reimplemented from Expression.

Definition at line 65 of file sequenceexpression.cpp.

References exps, getExps(), Expression::getType(), and unsetRecursiveDelete().

Expression * SequenceExpression::placeSignOffs ( vector< SignOffExpression * > & signoffs ) [virtual]

Places all signOff-statements in the corresponding query.

Places all signOff-statements in the corresponding query, which are needed for active garbage collection by removing Role from the BufferNode.

Parameters:

[in] signoffs Pointer to a vector containing Pointer to SignOffExpression objects.

Return values:

Expression*

Pointer to a Expression object (following expression in the corresponding query).

Reimplemented from Expression.

Definition at line 106 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::print ( OutputStream & dos ) const [virtual]

Prints the expression.

Parameters:

[in] dos Pointer to a OutputStream object.

Return values:

void

Implements Expression.

Definition at line 156 of file sequenceexpression.cpp.

References decrementIndents(), exps, Expression::getType(), incrementIndents(), NEWLINE, and writeIndents().

void SequenceExpression::replaceVarId	(	unsigned	old_id,
		unsigned	new_id
	)			`[virtual]`

Replaces all matching variable IDs by a new one.

Replaces all matching variable IDs by a new one, which is needed in case of calling method rewriteVarsteps().

Parameters:

`[in]`	old_id	Old variable ID.
`[in]`	new_id	New variable ID, which should be introduced instead.

Return values:

void

Reimplemented from Expression.

Definition at line 59 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::rewriteAggregateFuncts ( ) [virtual]

Rewrites all arguments of all aggregate functions into an equivalent for-clause (with return-clause).

Return values:

void

Reimplemented from Expression.

Definition at line 133 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::rewriteEmptyFuncts ( ) [virtual]

Rewrites all fn:empty XQuery functions into equivalent fn:not(fn:exists) XQuery functions.

Return values:

void

Reimplemented from Expression.

Definition at line 121 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::rewriteVarstepCondExps ( ) [virtual]

Rewrites all if($x) if-conditions into equivalent if(fn:not(fn:empty($x))) XQuery expressions.

Return values:

void

Reimplemented from Expression.

Definition at line 127 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::rewriteVarsteps ( ) [virtual]

Rewrites all varstep expressions, which produces output into an equivalent for-clause (with return-clause).

Rewrites all varstep expressions, which produces output into an equivalent for-clause (with return-clause). This method belongs to the 'earlier execution of signoff-statements' optimization.

Return values:

void

Reimplemented from Expression.

Definition at line 139 of file sequenceexpression.cpp.

References VarExpression::clone(), exps, VarName::getInstance(), and Expression::getType().

void SequenceExpression::rewriteWhereExps ( ) [virtual]

Rewrites all where-clauses in the query into equivalent if-expressions.

Rewrites all where-clauses in the query into equivalent if-expressions, i.e. rewrites all WhereExpression into equivalent IfExpression.

Return values:

void

Reimplemented from Expression.

Definition at line 115 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::scopeCheck	(	vector< unsigned > &	def_vars,
		vector< unsigned > &	introduced_vars,
		vector< unsigned > &	violating_vars
	)			`[virtual]`

Returns if all used variables were previously (through a for-clause) defined or if a variable leaves their defined scope.

Parameters:

`[in]`	def_vars	Vector containing all previously defined variables.
`[in]`	introduced_vars	Vector containing all up to this expression defined variables.
`[in]`	violating_vars	Vector containing all variables which violates the scope condition.

Return values:

void

Reimplemented from Expression.

Definition at line 49 of file sequenceexpression.cpp.

References exps.

void SequenceExpression::unsetRecursiveDelete ( ) [inline]

Resets recursive delete of this object.

Resets recursive delete of this object, i.e. on delete of this object subexpressions will not be deleted recursively.

Return values:

void

Definition at line 161 of file sequenceexpression.h.

Referenced by mergeSequences().

Member Data Documentation

bool SequenceExpression::delete_recursively [private]

Indicator to change delete behaviour when the destructor is called.

true will delete sequences recursively, false otherwise.

Definition at line 190 of file sequenceexpression.h.

Referenced by ~SequenceExpression().

vector< Expression * > SequenceExpression::exps [private]

The entered (sequence of) XQuery expressions.

The entered (sequence of) XQuery expressions, which are the arguments of the constructor.

Definition at line 184 of file sequenceexpression.h.

Referenced by containsDirectOutput(), eval(), extractDependencies(), extractFSAMap(), extractParVarMap(), getExps(), init(), insertExp(), mergeSequences(), placeSignOffs(), print(), replaceVarId(), rewriteAggregateFuncts(), rewriteEmptyFuncts(), rewriteVarstepCondExps(), rewriteVarsteps(), rewriteWhereExps(), scopeCheck(), SequenceExpression(), and ~SequenceExpression().


Public Member Functions
	SequenceExpression (Expression _left, Expression _right)
	Constructor.
virtual	~SequenceExpression ()
virtual void	scopeCheck (vector< unsigned > &def_vars, vector< unsigned > &introduced_vars, vector< unsigned > &violating_vars)
virtual void	replaceVarId (unsigned old_id, unsigned new_id)
virtual void	mergeSequences ()
virtual void	extractFSAMap (FSAMap *fsamap, unsigned parent_var)
virtual void	extractParVarMap (ParVarMap *parvarmap)
virtual void	extractDependencies (vector< DependencySet * > *depset)
virtual Expression *	placeSignOffs (vector< SignOffExpression * > &signoffs)
virtual void	rewriteWhereExps ()
virtual void	rewriteEmptyFuncts ()
virtual void	rewriteVarstepCondExps ()
virtual void	rewriteAggregateFuncts ()
virtual void	rewriteVarsteps ()
virtual void	print (OutputStream &dos) const
virtual void	init (BufferNode *root)
virtual void	eval (OutputStream &eos, Environment *env, unsigned modus)
void	insertExp (Expression *exp)
	Inserts a new expression to this sequence of XQuery expressions.
void	unsetRecursiveDelete ()
	Resets recursive delete of this object.
virtual bool	containsDirectOutput ()
Private Member Functions
vector< Expression * > *	getExps ()
	Returns the sequence of XQuery expressions.
Private Attributes
vector< Expression * >	exps
	The entered (sequence of) XQuery expressions.
bool	delete_recursively
	Indicator to change delete behaviour when the destructor is called.