QGIS API Documentation
3.0.2-Girona (307d082)
|
Single scope for storing variables and functions for use within a QgsExpressionContext. More...
#include <qgsexpressioncontext.h>
Classes | |
struct | StaticVariable |
Single variable definition for use within a QgsExpressionContextScope. More... | |
Public Member Functions | |
QgsExpressionContextScope (const QString &name=QString()) | |
Constructor for QgsExpressionContextScope. More... | |
QgsExpressionContextScope (const QgsExpressionContextScope &other) | |
Copy constructor. More... | |
~QgsExpressionContextScope () | |
void | addFunction (const QString &name, QgsScopedExpressionFunction *function) |
Adds a function to the scope. More... | |
void | addVariable (const QgsExpressionContextScope::StaticVariable &variable) |
Adds a variable into the context scope. More... | |
QString | description (const QString &name) const |
Returns the translated description for the variable with the specified name (if set). More... | |
QgsFeature | feature () const |
Sets the feature associated with the scope. More... | |
QStringList | filteredVariableNames () const |
Returns a filtered and sorted list of variable names contained within the scope. More... | |
QgsExpressionFunction * | function (const QString &name) const |
Retrieves a function from the scope. More... | |
QStringList | functionNames () const |
Retrieves a list of names of functions contained in the scope. More... | |
bool | hasFeature () const |
Returns true if the scope has a feature associated with it. More... | |
bool | hasFunction (const QString &name) const |
Tests whether a function with the specified name exists in the scope. More... | |
bool | hasVariable (const QString &name) const |
Tests whether a variable with the specified name exists in the scope. More... | |
bool | isReadOnly (const QString &name) const |
Tests whether the specified variable is read only and should not be editable by users. More... | |
bool | isStatic (const QString &name) const |
Tests whether the variable with the specified name is static and can be cached. More... | |
QString | name () const |
Returns the friendly display name of the context scope. More... | |
QgsExpressionContextScope & | operator= (const QgsExpressionContextScope &other) |
void | removeFeature () |
Removes any feature associated with the scope. More... | |
bool | removeVariable (const QString &name) |
Removes a variable from the context scope, if found. More... | |
void | setFeature (const QgsFeature &feature) |
Convenience function for setting a feature for the scope. More... | |
void | setFields (const QgsFields &fields) |
Convenience function for setting a fields for the scope. More... | |
void | setVariable (const QString &name, const QVariant &value, bool isStatic=false) |
Convenience method for setting a variable in the context scope by name name and value. More... | |
QVariant | variable (const QString &name) const |
Retrieves a variable's value from the scope. More... | |
int | variableCount () const |
Returns the count of variables contained within the scope. More... | |
QStringList | variableNames () const |
Returns a list of variable names contained within the scope. More... | |
Single scope for storing variables and functions for use within a QgsExpressionContext.
Examples include a project's scope, which could contain information about the current project such as the project file's location. QgsExpressionContextScope can encapsulate both variables (static values) and functions(which are calculated only when an expression is evaluated).
See QgsExpressionContextUtils for helper methods for working with QgsExpressionContextScope objects.
Definition at line 129 of file qgsexpressioncontext.h.
QgsExpressionContextScope::QgsExpressionContextScope | ( | const QString & | name = QString() | ) |
Constructor for QgsExpressionContextScope.
name | friendly display name for the context scope |
Definition at line 55 of file qgsexpressioncontext.cpp.
QgsExpressionContextScope::QgsExpressionContextScope | ( | const QgsExpressionContextScope & | other | ) |
Copy constructor.
Definition at line 61 of file qgsexpressioncontext.cpp.
QgsExpressionContextScope::~QgsExpressionContextScope | ( | ) |
Definition at line 92 of file qgsexpressioncontext.cpp.
void QgsExpressionContextScope::addFunction | ( | const QString & | name, |
QgsScopedExpressionFunction * | function | ||
) |
Adds a function to the scope.
name | function name |
function | function to insert. Ownership is transferred to the scope. |
Definition at line 212 of file qgsexpressioncontext.cpp.
void QgsExpressionContextScope::addVariable | ( | const QgsExpressionContextScope::StaticVariable & | variable | ) |
Adds a variable into the context scope.
If a variable with the same name is already set then its value is overwritten, otherwise a new variable is added to the scope.
variable | definition of variable to insert |
Definition at line 112 of file qgsexpressioncontext.cpp.
QString QgsExpressionContextScope::description | ( | const QString & | name | ) | const |
Returns the translated description for the variable with the specified name (if set).
Definition at line 192 of file qgsexpressioncontext.cpp.
|
inline |
Sets the feature associated with the scope.
Definition at line 326 of file qgsexpressioncontext.h.
QStringList QgsExpressionContextScope::filteredVariableNames | ( | ) | const |
Returns a filtered and sorted list of variable names contained within the scope.
Hidden variable names will be excluded, and the list will be sorted so that read only variables are listed first.
Definition at line 165 of file qgsexpressioncontext.cpp.
QgsExpressionFunction * QgsExpressionContextScope::function | ( | const QString & | name | ) | const |
Retrieves a function from the scope.
name | function name |
Definition at line 202 of file qgsexpressioncontext.cpp.
QStringList QgsExpressionContextScope::functionNames | ( | ) | const |
Retrieves a list of names of functions contained in the scope.
Definition at line 207 of file qgsexpressioncontext.cpp.
|
inline |
Returns true if the scope has a feature associated with it.
Definition at line 318 of file qgsexpressioncontext.h.
bool QgsExpressionContextScope::hasFunction | ( | const QString & | name | ) | const |
Tests whether a function with the specified name exists in the scope.
name | function name |
Definition at line 197 of file qgsexpressioncontext.cpp.
bool QgsExpressionContextScope::hasVariable | ( | const QString & | name | ) | const |
Tests whether a variable with the specified name exists in the scope.
name | variable name |
Definition at line 122 of file qgsexpressioncontext.cpp.
bool QgsExpressionContextScope::isReadOnly | ( | const QString & | name | ) | const |
Tests whether the specified variable is read only and should not be editable by users.
name | variable name |
Definition at line 182 of file qgsexpressioncontext.cpp.
bool QgsExpressionContextScope::isStatic | ( | const QString & | name | ) | const |
Tests whether the variable with the specified name is static and can be cached.
Definition at line 187 of file qgsexpressioncontext.cpp.
|
inline |
Returns the friendly display name of the context scope.
Definition at line 189 of file qgsexpressioncontext.h.
QgsExpressionContextScope & QgsExpressionContextScope::operator= | ( | const QgsExpressionContextScope & | other | ) |
Definition at line 74 of file qgsexpressioncontext.cpp.
|
inline |
Removes any feature associated with the scope.
Definition at line 343 of file qgsexpressioncontext.h.
bool QgsExpressionContextScope::removeVariable | ( | const QString & | name | ) |
Removes a variable from the context scope, if found.
name | name of variable to remove |
Definition at line 117 of file qgsexpressioncontext.cpp.
|
inline |
Convenience function for setting a feature for the scope.
Any existing feature set by the scope will be overwritten.
feature | feature for scope |
Definition at line 335 of file qgsexpressioncontext.h.
void QgsExpressionContextScope::setFields | ( | const QgsFields & | fields | ) |
Convenience function for setting a fields for the scope.
Any existing fields set by the scope will be overwritten.
fields | fields for scope |
Definition at line 218 of file qgsexpressioncontext.cpp.
void QgsExpressionContextScope::setVariable | ( | const QString & | name, |
const QVariant & | value, | ||
bool | isStatic = false |
||
) |
Convenience method for setting a variable in the context scope by name name and value.
If a variable with the same name is already set then its value is overwritten, otherwise a new variable is added to the scope. If the isStatic parameter is set to true, this variable can be cached during the execution of QgsExpression::prepare().
Definition at line 97 of file qgsexpressioncontext.cpp.
QVariant QgsExpressionContextScope::variable | ( | const QString & | name | ) | const |
Retrieves a variable's value from the scope.
name | variable name |
Definition at line 127 of file qgsexpressioncontext.cpp.
|
inline |
Returns the count of variables contained within the scope.
Definition at line 277 of file qgsexpressioncontext.h.
QStringList QgsExpressionContextScope::variableNames | ( | ) | const |
Returns a list of variable names contained within the scope.
Definition at line 132 of file qgsexpressioncontext.cpp.