org.gvsig.fmap.dal.feature

Interface FeatureQuery

All Superinterfaces:

Cloneable, DataQuery, Persistent

All Known Implementing Classes:

DefaultFeatureQuery

public interface FeatureQuery
extends DataQuery, Cloneable

Defines the properties of a collection of Features, as a result of a query through a FeatureStore.

A FeatureQuery is always defined by a FeatureType, or by the list of attribute names of the FeatureStore to return.

The filter allows to select Features whose properties have values with the characteristics defined by the filter.

The order is used to set the order of the result FeatureCollection, based on the values of the properties of the Features.

The scale parameter can be used by the FeatureStore as a hint about the quality or resolution of the data needed to view or operate with the data returned. As an example, the FeatureStore may use the scale to return only a representative subset of the data, or maybe to return Features with less detail, like a point or a line instead of a polygon.

If an implementation of FeatureStore is able to get other parameters to customize the behavior of the getDataCollection methods, there is an option to set more parameters through the setAttribute method.

Method Summary

Modifier and Type	Method and Description
void	addAttributeName(String attributeName) Adds the name of an attribute that has to be used to load each Feature.
void	addConstantAttributeName(String attributeName) Add an attribute name that will be treated as constant for each Feature.
void	addEssentialAttributeNames(FeatureStore store)
void	addFilter(Evaluator filter) Adds a filter to apply to the Features to load.
void	addFilter(String filter)
void	addPrimaryKeyAttributeNames(FeatureStore store)
void	clearAttributeNames() Remove all the attribute names specifieds.
void	clearConstantsAttributeNames() Remove all the names specified as constants attributes.
void	clearFilter()
String[]	getAttributeNames() Returns the names of the attributes to load from each Feature.
String[]	getConstantsAttributeNames() Returns the names of the attributes that are constants in each Feature.
FeatureQuery	getCopy() Deprecated. to be removed in gvSIG 2.0
String	getFeatureTypeId() Returns the FeatureType id of the Features to load.
Evaluator	getFilter() Returns the filter to apply to the Features to load.
long	getLimit() Returns the maximum number of elements to return with this query.
FeatureQueryOrder	getOrder() Returns the order of the Features to load.
long	getPageSize() Returns the load page size, as the number of elements to be retrieved in block by the data source.
boolean	hasAttributeNames() Return true if has set attribute names
boolean	hasConstantsAttributeNames() Return true if has set constants attribute names
boolean	hasFilter() Returns if a filter has been defined for the query.
boolean	hasOrder() Returns if an order has been set for the elements returned by the query.
void	retrievesAllAttributes()
void	setAttributeNames(String[] attributeNames) Sets the names of the attributes to load from each Feature.
void	setConstantsAttributeNames(String[] attributeNames) Set of attribute names to be treated as constants for each Feature.
void	setFeatureType(FeatureType featureType) Sets the FeatureType of the Features to load.
void	setFeatureTypeId(String featureTypeId) Sets the FeatureType id of the Features to load.
void	setFilter(Evaluator filter) Sets the filter to apply to the Features to load.
void	setFilter(String filter)
void	setLimit(long limit) Sets the maximum number of elements to return with this query.
void	setOrder(FeatureQueryOrder order) Sets the order of the Features to load.
void	setPageSize(long pageSize) Sets the load page size, as the number of elements to be retrieved in block by the data source.

Methods inherited from interface org.gvsig.fmap.dal.DataQuery

getQueryParameter, getScale, setQueryParameter, setScale

Methods inherited from interface org.gvsig.tools.persistence.Persistent

loadFromState, saveToState

Methods inherited from interface org.gvsig.tools.lang.Cloneable

clone

Method Detail

getAttributeNames

String[] getAttributeNames()

Returns the names of the attributes to load from each Feature.

Returns:

the attribute names to load

setAttributeNames

void setAttributeNames(String[] attributeNames)

Sets the names of the attributes to load from each Feature.

Parameters:

attributeNames - the attribute names to load

retrievesAllAttributes

void retrievesAllAttributes()

addAttributeName

void addAttributeName(String attributeName)

Adds the name of an attribute that has to be used to load each Feature.

Parameters:

attributeName - the attribute name to load

addPrimaryKeyAttributeNames

void addPrimaryKeyAttributeNames(FeatureStore store)

addEssentialAttributeNames

void addEssentialAttributeNames(FeatureStore store)

hasAttributeNames

boolean hasAttributeNames()

Return true if has set attribute names

Returns:

true if has attribute names, otherwise false

clearAttributeNames

void clearAttributeNames()

Remove all the attribute names specifieds.

getConstantsAttributeNames

String[] getConstantsAttributeNames()

Returns the names of the attributes that are constants in each Feature. These attributes will not be charged.

Returns:

the attribute names that are constant

setConstantsAttributeNames

void setConstantsAttributeNames(String[] attributeNames)

Set of attribute names to be treated as constants for each Feature.

Parameters:

attributeNames - the attribute names to be constants

addConstantAttributeName

void addConstantAttributeName(String attributeName)

Add an attribute name that will be treated as constant for each Feature.

Parameters:

attributeName - the attribute name to be treated as constant

hasConstantsAttributeNames

boolean hasConstantsAttributeNames()

Return true if has set constants attribute names

Returns:

true if has constants attribute names, otherwise false

clearConstantsAttributeNames

void clearConstantsAttributeNames()

Remove all the names specified as constants attributes.

setFeatureType

void setFeatureType(FeatureType featureType)

Sets the FeatureType of the Features to load. It may be used as an alternative way to set a subset of the list of attribute names to load, by creating a sub-FeatureType.

Parameters:

featureType - the feature type of the data to load

getFeatureTypeId

String getFeatureTypeId()

Returns the FeatureType id of the Features to load.

Returns:

the FeatureType id of the Features to load

setFeatureTypeId

void setFeatureTypeId(String featureTypeId)

Sets the FeatureType id of the Features to load. This way all Feature attributes will be loaded.

Parameters:

featureTypeId - the FeatureType id of the Features to load

getFilter

Evaluator getFilter()

Returns the filter to apply to the Features to load.

Returns:

the filter

setFilter

void setFilter(Evaluator filter)

Sets the filter to apply to the Features to load.

Parameters:

filter - the filter to apply to the Features to load

setFilter

void setFilter(String filter)

addFilter

void addFilter(Evaluator filter)

Adds a filter to apply to the Features to load. A query can have more that one filter and all of them are applied when the query is applied. If filter is null do nothing.

Parameters:

filter - a filter to apply to the Features to load

addFilter

void addFilter(String filter)

clearFilter

void clearFilter()

hasFilter

boolean hasFilter()

Returns if a filter has been defined for the query.

Returns:

if a filter has been defined for the query

getOrder

FeatureQueryOrder getOrder()

Returns the order of the Features to load.

Returns:

the order of the Features to load

setOrder

void setOrder(FeatureQueryOrder order)

Sets the order of the Features to load.

Parameters:

order - the order of the Features to load

hasOrder

boolean hasOrder()

Returns if an order has been set for the elements returned by the query.

Returns:

if an order has been set for the elements returned by the query

getCopy

FeatureQuery getCopy()

Deprecated. to be removed in gvSIG 2.0

Returns:

See Also:

Cloneable.clone()

getLimit

long getLimit()

Returns the maximum number of elements to return with this query.

NOTE: this value may be ignored by the underlying data source, or only used as a hint, so don't rely on it being used, as you may actually get more values than the limit.

Returns:

the maximum number of elements to return with this query

setLimit

void setLimit(long limit)

Sets the maximum number of elements to return with this query.

NOTE: this value may be ignored by the underlying data source, or only used as a hint, so don't rely on it being used, as you may actually get more values than the limit.

Parameters:

limit - the maximum number of elements to return with this query

getPageSize

long getPageSize()

Returns the load page size, as the number of elements to be retrieved in block by the data source. This value is only used as a hint to the underlying data source, as a way to tell how many Features may be read in a block.

Returns:

the load page size

setPageSize

void setPageSize(long pageSize)

Sets the load page size, as the number of elements to be retrieved in block by the data source. This value is only used as a hint to the underlying data source, as a way to tell how many Features may be read in a block.

Parameters:

pageSize - the load page size