org.deegree.feature.persistence.query
Class Query

java.lang.Object
  org.deegree.feature.persistence.query.Query

public class Query
extends Object

Encapsulates the parameter of a query to a FeatureStore.

Version:

$Revision: 30887 $, $Date: 2011-05-23 10:57:10 +0200 (Mon, 23 May 2011) $

Author:

Markus Schneider, last edited by: $Author: aschmitz $

Nested Class Summary

static class

Query.QueryHint Names for hints and additional parameters that a FeatureStore implementation may take into account to increase efficient query processing.

Constructor Summary

Query(IdFilter filter, String featureVersion, ICRS srsName, SortProperty[] sortBy)
Creates a new Query instance that selects features based on an IdFilter.

Query(QName ftName, Filter filter, int scale, int maxFeatures, double resolution)
Creates a new Query instance.

Query(TypeName[] typeNames, Filter filter, String featureVersion, ICRS srsName, SortProperty[] sortBy)
Creates a new Query instance.

Method Summary

Filter	getFilter() Returns the Filter.
Object	getHint(Query.QueryHint code)
int	getMaxFeatures()
Envelope	getPrefilterBBox() Returns an Envelope suitable for performing a spatial pre-filtering step on the set of feature candidates.
SortProperty[]	getSortProperties() Returns the sort criteria.
TypeName[]	getTypeNames() Returns the names of the requested feature types.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Query

public Query(QName ftName,
             Filter filter,
             int scale,
             int maxFeatures,
             double resolution)

Creates a new Query instance.

Parameters:

ftName - name of the requested feature type, must not be null

filter - additional filter constraints, may be null, if not null, all contained geometry operands must have a non-null CRS

scale - if scale is positive, a scale query hint will be used

maxFeatures - may be -1 if no limit needs to be exercised

resolution - if resolution is positive, a pixel resolution hint will be used

Query

public Query(TypeName[] typeNames,
             Filter filter,
             String featureVersion,
             ICRS srsName,
             SortProperty[] sortBy)

Creates a new Query instance.

Parameters:

typeNames - feature type names to be queried, must not be null and contain at least one entry

filter - filter to be applied, can be null, if not null, all contained geometry operands must have a non-null CRS

featureVersion - specific feature version to be returned, can be null

srsName - SRS for the returned geometries, can be null

sortBy - sort criteria to be applied, can be null

Query

public Query(IdFilter filter,
             String featureVersion,
             ICRS srsName,
             SortProperty[] sortBy)

Creates a new Query instance that selects features based on an IdFilter.

Parameters:

filter - filter to be applied, must not be null

featureVersion - specific feature version to be returned, can be null

srsName - SRS for the returned geometries, can be null

sortBy - sort criteria to be applied, can be null

Method Detail

getHint

public Object getHint(Query.QueryHint code)

getPrefilterBBox

public Envelope getPrefilterBBox()

Returns an Envelope suitable for performing a spatial pre-filtering step on the set of feature candidates.

The returned Envelope is determined by the following strategy:

• If the Query contains an OperatorFilter, it is attempted to extract an Envelope from it. TODO Note that the envelope is only used when the corresponding property name targets a property of the root feature (and not a property of a subfeature).
• If no bbox can be extracted from the filter, null is returned.

Returns:

an Envelope suitable for pre-filtering feature candidates, can be null

getTypeNames

public TypeName[] getTypeNames()

Returns the names of the requested feature types.

Returns:

the names of the requested feature types, never null (but may be empty for id filter queries)

getFilter

public Filter getFilter()

Returns the Filter.

Returns:

filter, may be null

getSortProperties

public SortProperty[] getSortProperties()

Returns the sort criteria.

Returns:

the sort criteria, never null (but may be empty)

getMaxFeatures

public int getMaxFeatures()

Returns:

-1, if no limit has been set