NodeConstructExpression Class Reference

Represents an XQuery XML element with or without an expression inside. More...

#include <nodeconstructexpression.h>

Inheritance diagram for NodeConstructExpression:

Collaboration diagram for NodeConstructExpression:

List of all members.

Public Member Functions

NodeConstructExpression (const char *_tag, Expression *_exp)

Constructor.

virtual ~NodeConstructExpression ()

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)

Private Attributes

TAG tag

The entered TAG (tagname).

Expression * exp

The entered Expression.

Detailed Description

Represents an XQuery XML element with or without an expression inside.

Represents an XQuery XML element with or without an expression inside, which takes therefore a TAG as XML element and a Expression, e.g. <tag>fn:count($x)</tag> or <tag/>, as arguments.

Note:: In the case that there is no expression inside an XML element, this object is not initialized with NULL as Expression but instead an EmptyExpression is used!
Tagnames are internally represented by numbers!

Author:: Michael Schmidt
Gunnar Jehl

Version:: 2.1

License:: Software License Agreement (BSD License)

Definition at line 54 of file nodeconstructexpression.h.

Constructor & Destructor Documentation

NodeConstructExpression::NodeConstructExpression	(	const char *	_tag,
		Expression *	_exp
	)

Constructor.

Constructor - creating object for a string (tagname) and a Expression.

Parameters:

`[in]`	_tag	Pointer to a char object.
`[in]`	_exp	Pointer to a Expression object.

Definition at line 37 of file nodeconstructexpression.cpp.

NodeConstructExpression::~NodeConstructExpression ( ) [virtual]

Destructor.

Definition at line 45 of file nodeconstructexpression.cpp.

References exp.

Member Function Documentation

void NodeConstructExpression::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 139 of file nodeconstructexpression.cpp.

References Expression::eval(), EVAL_QUERY, EVAL_SIGNOFF, exp, TagMap::getTag(), Expression::getType(), tag, and Expression::tagmap.

void NodeConstructExpression::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 72 of file nodeconstructexpression.cpp.

References exp, and Expression::extractDependencies().

void NodeConstructExpression::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 63 of file nodeconstructexpression.cpp.

References exp, and Expression::extractFSAMap().

void NodeConstructExpression::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 68 of file nodeconstructexpression.cpp.

References exp, and Expression::extractParVarMap().

void NodeConstructExpression::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 135 of file nodeconstructexpression.cpp.

References exp, and Expression::init().

void NodeConstructExpression::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 59 of file nodeconstructexpression.cpp.

References exp, and Expression::mergeSequences().

Expression * NodeConstructExpression::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 77 of file nodeconstructexpression.cpp.

References exp, and Expression::placeSignOffs().

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

Prints the expression.

Parameters:

[in] dos Pointer to a OutputStream object.

Return values:

void

Implements Expression.

Definition at line 116 of file nodeconstructexpression.cpp.

References decrementIndents(), exp, TagMap::getTag(), Expression::getType(), incrementIndents(), NEWLINE, tag, Expression::tagmap, and writeIndents().

void NodeConstructExpression::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 55 of file nodeconstructexpression.cpp.

References exp, and Expression::replaceVarId().

void NodeConstructExpression::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 97 of file nodeconstructexpression.cpp.

References exp, and Expression::rewriteAggregateFuncts().

void NodeConstructExpression::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 89 of file nodeconstructexpression.cpp.

References exp, and Expression::rewriteEmptyFuncts().

void NodeConstructExpression::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 93 of file nodeconstructexpression.cpp.

References exp, and Expression::rewriteVarstepCondExps().

void NodeConstructExpression::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 101 of file nodeconstructexpression.cpp.

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

void NodeConstructExpression::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 85 of file nodeconstructexpression.cpp.

References exp, and Expression::rewriteWhereExps().

void NodeConstructExpression::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 nodeconstructexpression.cpp.

References exp, and Expression::scopeCheck().

Member Data Documentation

Expression * NodeConstructExpression::exp [private]

The entered Expression.

The entered Expression, which is the second argument of the constructor.

Definition at line 158 of file nodeconstructexpression.h.

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

TAG NodeConstructExpression::tag [private]

The entered TAG (tagname).

The entered TAG (tagname), which is the first argument of the constructor and internally represented by a number.

Definition at line 152 of file nodeconstructexpression.h.

Referenced by eval(), and print().


Public Member Functions
	NodeConstructExpression (const char _tag, Expression _exp)
	Constructor.
virtual	~NodeConstructExpression ()
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)
Private Attributes
TAG	tag
	The entered TAG (tagname).
Expression *	exp
	The entered Expression.