mirror of
https://github.com/qgis/QGIS.git
synced 2025-03-04 00:30:59 -05:00
f3e1772bb9
This enum value has not been in use since filter rects were separated from other filter types. Leaving it in API is confusing and leads to incorrect use.
352 lines
12 KiB
Plaintext
352 lines
12 KiB
Plaintext
|
|
class QgsFeatureRequest
|
|
{
|
|
%TypeHeaderCode
|
|
#include <qgsfeaturerequest.h>
|
|
%End
|
|
|
|
public:
|
|
enum Flag
|
|
{
|
|
NoFlags,
|
|
NoGeometry, //!< Geometry is not required. It may still be returned if e.g. required for a filter condition.
|
|
SubsetOfAttributes, //!< Fetch only a subset of attributes (setSubsetOfAttributes sets this flag)
|
|
ExactIntersect //!< Use exact geometry intersection (slower) instead of bounding boxes
|
|
};
|
|
typedef QFlags<QgsFeatureRequest::Flag> Flags;
|
|
|
|
/**
|
|
* Types of filters.
|
|
*/
|
|
enum FilterType
|
|
{
|
|
FilterNone, //!< No filter is applied
|
|
FilterFid, //!< Filter using feature ID
|
|
FilterExpression, //!< Filter using expression
|
|
FilterFids //!< Filter using feature IDs
|
|
};
|
|
|
|
/**
|
|
* The OrderByClause class represents an order by clause for a QgsFeatureRequest.
|
|
*
|
|
* It can be a simple field or an expression. Multiple order by clauses can be added to
|
|
* a QgsFeatureRequest to fine tune the behavior if a single field or expression is not
|
|
* enough to completely specify the required behavior.
|
|
*
|
|
* If expression compilation is activated in the settings and the expression can be
|
|
* translated for the provider in question, it will be evaluated on provider side.
|
|
* If one of these two premises does not apply, the ordering will take place locally
|
|
* which results in increased memory and CPU usage.
|
|
*
|
|
* If the ordering is done on strings, the order depends on the system's locale if the
|
|
* local fallback implementation is used. The order depends on the server system's locale
|
|
* and implementation if ordering is done on the server.
|
|
*
|
|
* In case the fallback code needs to be used, a limit set on the request will be respected
|
|
* for the features returned by the iterator but internally all features will be requested
|
|
* from the provider.
|
|
*
|
|
* @note added in QGIS 2.14
|
|
*/
|
|
class OrderByClause
|
|
{
|
|
public:
|
|
/**
|
|
* Creates a new OrderByClause for a QgsFeatureRequest
|
|
*
|
|
* @param expression The expression to use for ordering
|
|
* @param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
|
|
* If the order is ascending, by default nulls are last
|
|
* If the order is descending, by default nulls are first
|
|
*/
|
|
OrderByClause( const QString &expression, bool ascending = true );
|
|
/**
|
|
* Creates a new OrderByClause for a QgsFeatureRequest
|
|
*
|
|
* @param expression The expression to use for ordering
|
|
* @param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
|
|
* @param nullsfirst If true, NULLS are at the beginning, if false, NULLS are at the end
|
|
*/
|
|
OrderByClause( const QString &expression, bool ascending, bool nullsfirst );
|
|
|
|
/**
|
|
* The expression
|
|
* @return the expression
|
|
*/
|
|
QgsExpression expression() const;
|
|
|
|
/**
|
|
* Order ascending
|
|
* @return If ascending order is requested
|
|
*/
|
|
bool ascending() const;
|
|
|
|
/**
|
|
* Set if ascending order is requested
|
|
*/
|
|
void setAscending( bool ascending );
|
|
|
|
/**
|
|
* Set if NULLS should be returned first
|
|
* @return if NULLS should be returned first
|
|
*/
|
|
bool nullsFirst() const;
|
|
|
|
/**
|
|
* Set if NULLS should be returned first
|
|
*/
|
|
void setNullsFirst( bool nullsFirst );
|
|
|
|
/**
|
|
* Dumps the content to an SQL equivalent
|
|
*/
|
|
QString dump() const;
|
|
};
|
|
|
|
/**
|
|
* Represents a list of OrderByClauses, with the most important first and the least
|
|
* important last.
|
|
*
|
|
* @note added in QGIS 2.14
|
|
*/
|
|
class OrderBy
|
|
{
|
|
public:
|
|
/**
|
|
* Create a new empty order by
|
|
*/
|
|
OrderBy();
|
|
|
|
/**
|
|
* Create a new order by from a list of clauses
|
|
*/
|
|
OrderBy( const QList<QgsFeatureRequest::OrderByClause>& other );
|
|
|
|
/**
|
|
* Get a copy as a list of OrderByClauses
|
|
*
|
|
* This is only required in python where the inheritance
|
|
* is not properly propagated and this makes it usable.
|
|
*/
|
|
QList<QgsFeatureRequest::OrderByClause> list() const;
|
|
|
|
/**
|
|
* Serialize to XML
|
|
*/
|
|
void save( QDomElement& elem ) const;
|
|
|
|
/**
|
|
* Deserialize from XML
|
|
*/
|
|
void load( const QDomElement& elem );
|
|
|
|
/**
|
|
* Returns a set of used attributes
|
|
*/
|
|
QSet<QString> usedAttributes() const;
|
|
|
|
/**
|
|
* Dumps the content to an SQL equivalent syntax
|
|
*/
|
|
QString dump() const;
|
|
};
|
|
|
|
/**
|
|
* A special attribute that if set matches all attributes
|
|
*/
|
|
static const QString ALL_ATTRIBUTES;
|
|
|
|
//! construct a default request: for all features get attributes and geometries
|
|
QgsFeatureRequest();
|
|
//! construct a request with feature ID filter
|
|
explicit QgsFeatureRequest( QgsFeatureId fid );
|
|
//! construct a request with rectangle filter
|
|
explicit QgsFeatureRequest( const QgsRectangle& rect );
|
|
//! construct a request with a filter expression
|
|
explicit QgsFeatureRequest( const QgsExpression& expr, const QgsExpressionContext& context = QgsExpressionContext() );
|
|
//! copy constructor
|
|
QgsFeatureRequest( const QgsFeatureRequest& rh );
|
|
|
|
~QgsFeatureRequest();
|
|
|
|
/**
|
|
* Return the filter type which is currently set on this request
|
|
*
|
|
* @return Filter type
|
|
*/
|
|
FilterType filterType() const;
|
|
|
|
/**
|
|
* Set rectangle from which features will be taken. Empty rectangle removes the filter.
|
|
*/
|
|
QgsFeatureRequest& setFilterRect( const QgsRectangle& rect );
|
|
|
|
/**
|
|
* Get the rectangle from which features will be taken.
|
|
*/
|
|
const QgsRectangle& filterRect() const;
|
|
|
|
//! Set feature ID that should be fetched.
|
|
QgsFeatureRequest& setFilterFid( qint64 fid );
|
|
//! Get the feature ID that should be fetched.
|
|
qint64 filterFid() const;
|
|
|
|
//! Set feature IDs that should be fetched.
|
|
QgsFeatureRequest& setFilterFids( const QgsFeatureIds& fids );
|
|
//! Get feature IDs that should be fetched.
|
|
const QgsFeatureIds& filterFids() const;
|
|
|
|
/** Set the filter expression. {@see QgsExpression}
|
|
* @param expression expression string
|
|
* @see filterExpression
|
|
* @see setExpressionContext
|
|
*/
|
|
QgsFeatureRequest& setFilterExpression( const QString& expression );
|
|
|
|
/** Returns the filter expression if set.
|
|
* @see setFilterExpression
|
|
* @see expressionContext
|
|
*/
|
|
QgsExpression* filterExpression() const;
|
|
|
|
/** Modifies the existing filter expression to add an additional expression filter. The
|
|
* filter expressions are combined using AND, so only features matching both
|
|
* the existing expression and the additional expression will be returned.
|
|
* @note added in QGIS 2.14
|
|
*/
|
|
QgsFeatureRequest& combineFilterExpression( const QString& expression );
|
|
|
|
/** Returns the expression context used to evaluate filter expressions.
|
|
* @note added in QGIS 2.12
|
|
* @see setExpressionContext
|
|
* @see filterExpression
|
|
*/
|
|
QgsExpressionContext* expressionContext();
|
|
|
|
/** Sets the expression context used to evaluate filter expressions.
|
|
* @note added in QGIS 2.12
|
|
* @see expressionContext
|
|
* @see setFilterExpression
|
|
*/
|
|
QgsFeatureRequest& setExpressionContext( const QgsExpressionContext& context );
|
|
|
|
/**
|
|
* Disables filter conditions.
|
|
* The spatial filter (filterRect) will be kept in place.
|
|
*
|
|
* @return The object the method is called on for chaining
|
|
*
|
|
* @note Added in 2.12
|
|
*/
|
|
QgsFeatureRequest& disableFilter();
|
|
|
|
/**
|
|
* Adds a new OrderByClause, appending it as the least important one.
|
|
*
|
|
* @param expression The expression to use for ordering
|
|
* @param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
|
|
* If the order is ascending, by default nulls are last
|
|
* If the order is descending, by default nulls are first
|
|
*
|
|
* @note added in QGIS 2.14
|
|
*/
|
|
|
|
QgsFeatureRequest& addOrderBy( const QString &expression, bool ascending = true );
|
|
/**
|
|
* Adds a new OrderByClause, appending it as the least important one.
|
|
*
|
|
* @param expression The expression to use for ordering
|
|
* @param ascending If the order should be ascending (1,2,3) or descending (3,2,1)
|
|
* @param nullsfirst If true, NULLS are at the beginning, if false, NULLS are at the end
|
|
*
|
|
* @note added in QGIS 2.14
|
|
*/
|
|
QgsFeatureRequest& addOrderBy( const QString &expression, bool ascending, bool nullsfirst );
|
|
|
|
/**
|
|
* Return a list of order by clauses specified for this feature request.
|
|
*
|
|
* @note added in 2.14
|
|
*/
|
|
QgsFeatureRequest::OrderBy orderBy() const;
|
|
|
|
/**
|
|
* Set a list of order by clauses.
|
|
*
|
|
* @note added in 2.14
|
|
*/
|
|
QgsFeatureRequest& setOrderBy( const QgsFeatureRequest::OrderBy& orderBy );
|
|
|
|
/** Set the maximum number of features to request.
|
|
* @param limit maximum number of features, or -1 to request all features.
|
|
* @see limit()
|
|
* @note added in QGIS 2.14
|
|
*/
|
|
QgsFeatureRequest& setLimit( long limit );
|
|
|
|
/** Returns the maximum number of features to request, or -1 if no limit set.
|
|
* @see setLimit
|
|
* @note added in QGIS 2.14
|
|
*/
|
|
long limit() const;
|
|
|
|
//! Set flags that affect how features will be fetched
|
|
QgsFeatureRequest& setFlags( const Flags& flags );
|
|
const Flags& flags() const;
|
|
|
|
//! Set a subset of attributes that will be fetched. Empty list means that all attributes are used.
|
|
//! To disable fetching attributes, reset the FetchAttributes flag (which is set by default)
|
|
QgsFeatureRequest& setSubsetOfAttributes( const QgsAttributeList& attrs );
|
|
/**
|
|
* Return the subset of attributes which at least need to be fetched
|
|
* @return A list of attributes to be fetched
|
|
*/
|
|
QgsAttributeList subsetOfAttributes() const;
|
|
|
|
//! Set a subset of attributes by names that will be fetched
|
|
QgsFeatureRequest& setSubsetOfAttributes( const QStringList& attrNames, const QgsFields& fields );
|
|
|
|
//! Set a simplification method for geometries that will be fetched
|
|
//! @note added in 2.2
|
|
QgsFeatureRequest& setSimplifyMethod( const QgsSimplifyMethod& simplifyMethod );
|
|
//! Get simplification method for geometries that will be fetched
|
|
//! @note added in 2.2
|
|
const QgsSimplifyMethod& simplifyMethod() const;
|
|
|
|
/**
|
|
* Check if a feature is accepted by this requests filter
|
|
*
|
|
* @param feature The feature which will be tested
|
|
*
|
|
* @return true, if the filter accepts the feature
|
|
*
|
|
* @note added in 2.1
|
|
*/
|
|
bool acceptFeature( const QgsFeature& feature );
|
|
|
|
};
|
|
|
|
|
|
/** Base class that can be used for any class that is capable of returning features
|
|
* @note added in 2.4
|
|
*/
|
|
class QgsAbstractFeatureSource
|
|
{
|
|
%TypeHeaderCode
|
|
#include <qgsfeaturerequest.h>
|
|
%End
|
|
public:
|
|
virtual ~QgsAbstractFeatureSource();
|
|
|
|
/**
|
|
* Get an iterator for features matching the specified request
|
|
* @param request The request
|
|
* @return A feature iterator
|
|
*/
|
|
virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest& request ) = 0;
|
|
|
|
protected:
|
|
void iteratorOpened( QgsAbstractFeatureIterator* it );
|
|
void iteratorClosed( QgsAbstractFeatureIterator* it );
|
|
};
|