org.gvsig.fmap.dal.feature.impl

Class DefaultFeatureQuery

java.lang.Object

org.gvsig.fmap.dal.feature.impl.DefaultFeatureQuery

All Implemented Interfaces:

Cloneable, DataQuery, FeatureQuery, Persistent

public class DefaultFeatureQuery
extends Object
implements FeatureQuery

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.

Field Summary

Fields

Modifier and Type	Field and Description
static String	SCALE_PARAM_NAME

Constructor Summary

Constructors

Constructor and Description
DefaultFeatureQuery() Creates a FeatureQuery which will load all available Features of a type.
DefaultFeatureQuery(FeatureType featureType) Creates a FeatureQuery which will load all available Features of a type.
DefaultFeatureQuery(FeatureType featureType, Evaluator filter) Creates a FeatureQuery with the type of features, a filter and the order for the FeatureCollection.
DefaultFeatureQuery(FeatureType featureType, Evaluator filter, double scale) Creates a FeatureQuery with the type of features, a filter, the order for the FeatureCollection and the view scale.
DefaultFeatureQuery(String[] attributeNames) Creates a FeatureQuery which will load a list of attribute names of all available Features.
DefaultFeatureQuery(String[] attributeNames, Evaluator filter) Creates a FeatureQuery with the list of attribute names of feature, a filter and the order for the FeatureCollection.
DefaultFeatureQuery(String[] attributeNames, Evaluator filter, double scale) Creates a FeatureQuery with the list of attribute names of feature, a filter, the order for the FeatureCollection and the view scale.

Method Summary

Methods

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	addFilter(Evaluator evaluator) Adds a filter to apply to the Features to load.
void	clearAttributeNames() Remove all the attribute names specifieds.
void	clearConstantsAttributeNames() Remove all the names specified as constants attributes.
Object	clone() Creates a copy of the object.
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()
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.
Object	getQueryParameter(String name) Returns the value of an query parameter.
double	getScale() Returns the scale of the data to load.
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	loadFromState(PersistentState state) Set the state of the object from the state passed as parameter.
static void	registerPersistent() Register the class on PersistenceManager
void	saveToState(PersistentState state) Saves the internal state of the object on the provided PersistentState object.
void	setAttributeNames(String[] attributeNames) Sets the names of the attributes to load from each Feature.
void	setConstantsAttributeNames(String[] constantsAttributeNames) 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	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.
void	setQueryParameter(String name, Object value) Sets the value of an query parameter.
void	setScale(double scale) Sets the scale.

Methods inherited from class java.lang.Object

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

Field Detail

SCALE_PARAM_NAME

public static final String SCALE_PARAM_NAME

See Also:

Constant Field Values

Constructor Detail

DefaultFeatureQuery

public DefaultFeatureQuery()

Creates a FeatureQuery which will load all available Features of a type.

Parameters:

featureType - the type of Features of the query

DefaultFeatureQuery

public DefaultFeatureQuery(FeatureType featureType)

Creates a FeatureQuery which will load all available Features of a type.

Parameters:

featureType - the type of Features of the query

DefaultFeatureQuery

public DefaultFeatureQuery(FeatureType featureType,
                   Evaluator filter)

Creates a FeatureQuery with the type of features, a filter and the order for the FeatureCollection.

Parameters:

featureType - the type of Features of the query

filter - based on the properties of the Features

order - for the result

DefaultFeatureQuery

public DefaultFeatureQuery(FeatureType featureType,
                   Evaluator filter,
                   double scale)

Creates a FeatureQuery with the type of features, a filter, the order for the FeatureCollection and the view scale.

Parameters:

featureType - the type of Features of the query

filter - based on the properties of the Features

order - for the result

scale - to view the Features.

DefaultFeatureQuery

public DefaultFeatureQuery(String[] attributeNames)

Creates a FeatureQuery which will load a list of attribute names of all available Features.

Parameters:

attributeNames - the list of attribute names to load

DefaultFeatureQuery

public DefaultFeatureQuery(String[] attributeNames,
                   Evaluator filter)

Creates a FeatureQuery with the list of attribute names of feature, a filter and the order for the FeatureCollection.

Parameters:

attributeNames - the list of attribute names to load

filter - based on the properties of the Features

order - for the result

DefaultFeatureQuery

public DefaultFeatureQuery(String[] attributeNames,
                   Evaluator filter,
                   double scale)

Creates a FeatureQuery with the list of attribute names of feature, a filter, the order for the FeatureCollection and the view scale.

Parameters:

attributeNames - the list of attribute names to load

filter - based on the properties of the Features

order - for the result

scale - to view the Features.

Method Detail

getScale

public double getScale()

Description copied from interface: DataQuery

Returns the scale of the data to load.

Specified by:

getScale in interface DataQuery

Returns:

the scale of the data to load

setScale

public void setScale(double scale)

Description copied from interface: DataQuery

Sets the scale.

Specified by:

setScale in interface DataQuery

Parameters:

scale - the scale to set

getQueryParameter

public Object getQueryParameter(String name)

Description copied from interface: DataQuery

Returns the value of an query parameter.

Specified by:

getQueryParameter in interface DataQuery

Parameters:

name - of the parameter

Returns:

the parameter value

setQueryParameter

public void setQueryParameter(String name,
                     Object value)

Description copied from interface: DataQuery

Sets the value of an query parameter.

Specified by:

setQueryParameter in interface DataQuery

Parameters:

name - of the query parameter

value - for the query parameter

setFeatureType

public void setFeatureType(FeatureType featureType)

Description copied from interface: FeatureQuery

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.

Specified by:

setFeatureType in interface FeatureQuery

Parameters:

featureType - the feature type of the data to load

getAttributeNames

public String[] getAttributeNames()

Description copied from interface: FeatureQuery

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

Specified by:

getAttributeNames in interface FeatureQuery

Returns:

the attribute names to load

setAttributeNames

public void setAttributeNames(String[] attributeNames)

Description copied from interface: FeatureQuery

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

Specified by:

setAttributeNames in interface FeatureQuery

Parameters:

attributeNames - the attribute names to load

addAttributeName

public void addAttributeName(String attributeName)

Description copied from interface: FeatureQuery

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

Specified by:

addAttributeName in interface FeatureQuery

Parameters:

attributeName - the attribute name to load

hasAttributeNames

public boolean hasAttributeNames()

Description copied from interface: FeatureQuery

Return true if has set attribute names

Specified by:

hasAttributeNames in interface FeatureQuery

Returns:

true if has attribute names, otherwise false

clearAttributeNames

public void clearAttributeNames()

Description copied from interface: FeatureQuery

Remove all the attribute names specifieds.

Specified by:

clearAttributeNames in interface FeatureQuery

getFilter

public Evaluator getFilter()

Description copied from interface: FeatureQuery

Returns the filter to apply to the Features to load.

Specified by:

getFilter in interface FeatureQuery

Returns:

the filter

setFilter

public void setFilter(Evaluator filter)

Description copied from interface: FeatureQuery

Sets the filter to apply to the Features to load.

Specified by:

setFilter in interface FeatureQuery

Parameters:

filter - the filter to apply to the Features to load

addFilter

public void addFilter(Evaluator evaluator)

Description copied from interface: FeatureQuery

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.

Specified by:

addFilter in interface FeatureQuery

Parameters:

evaluator - a filter to apply to the Features to load

getOrder

public FeatureQueryOrder getOrder()

Description copied from interface: FeatureQuery

Returns the order of the Features to load.

Specified by:

getOrder in interface FeatureQuery

Returns:

the order of the Features to load

setOrder

public void setOrder(FeatureQueryOrder order)

Description copied from interface: FeatureQuery

Sets the order of the Features to load.

Specified by:

setOrder in interface FeatureQuery

Parameters:

order - the order of the Features to load

hasFilter

public boolean hasFilter()

Description copied from interface: FeatureQuery

Returns if a filter has been defined for the query.

Specified by:

hasFilter in interface FeatureQuery

Returns:

if a filter has been defined for the query

hasOrder

public boolean hasOrder()

Description copied from interface: FeatureQuery

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

Specified by:

hasOrder in interface FeatureQuery

Returns:

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

clone

public Object clone()
             throws CloneNotSupportedException

Description copied from interface: Cloneable

Creates a copy of the object.

Overrides:

clone in class Object

Returns:

a copy of the object

Throws:

CloneNotSupportedException - if the instance of the object cannot be cloned. As this is extending Cloneable so its sure it implements it, so this exception may be used for problems on specific object instances.

See Also:

Object#clone()}.

getCopy

public FeatureQuery getCopy()

Specified by:

getCopy in interface FeatureQuery

See Also:

Cloneable.clone()

getFeatureTypeId

public String getFeatureTypeId()

Description copied from interface: FeatureQuery

Returns the FeatureType id of the Features to load.

Specified by:

getFeatureTypeId in interface FeatureQuery

Returns:

the FeatureType id of the Features to load

setFeatureTypeId

public void setFeatureTypeId(String featureTypeId)

Description copied from interface: FeatureQuery

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

Specified by:

setFeatureTypeId in interface FeatureQuery

Parameters:

featureTypeId - the FeatureType id of the Features to load

saveToState

public void saveToState(PersistentState state)
                 throws PersistenceException

Description copied from interface: Persistent

Saves the internal state of the object on the provided PersistentState object.

Specified by:

saveToState in interface Persistent

Throws:

PersistenceException

loadFromState

public void loadFromState(PersistentState state)
                   throws PersistenceException

Description copied from interface: Persistent

Set the state of the object from the state passed as parameter.

Specified by:

loadFromState in interface Persistent

Throws:

PersistenceException

registerPersistent

public static void registerPersistent()

Register the class on PersistenceManager

getLimit

public long getLimit()

Description copied from interface: FeatureQuery

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.

Specified by:

getLimit in interface FeatureQuery

Returns:

the maximum number of elements to return with this query

getPageSize

public long getPageSize()

Description copied from interface: FeatureQuery

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.

Specified by:

getPageSize in interface FeatureQuery

Returns:

the load page size

setLimit

public void setLimit(long limit)

Description copied from interface: FeatureQuery

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.

Specified by:

setLimit in interface FeatureQuery

Parameters:

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

setPageSize

public void setPageSize(long pageSize)

Description copied from interface: FeatureQuery

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.

Specified by:

setPageSize in interface FeatureQuery

Parameters:

pageSize - the load page size

getConstantsAttributeNames

public String[] getConstantsAttributeNames()

Description copied from interface: FeatureQuery

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

Specified by:

getConstantsAttributeNames in interface FeatureQuery

Returns:

the attribute names that are constant

setConstantsAttributeNames

public void setConstantsAttributeNames(String[] constantsAttributeNames)

Description copied from interface: FeatureQuery

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

Specified by:

setConstantsAttributeNames in interface FeatureQuery

Parameters:

constantsAttributeNames - the attribute names to be constants

addConstantAttributeName

public void addConstantAttributeName(String attributeName)

Description copied from interface: FeatureQuery

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

Specified by:

addConstantAttributeName in interface FeatureQuery

Parameters:

attributeName - the attribute name to be treated as constant

hasConstantsAttributeNames

public boolean hasConstantsAttributeNames()

Description copied from interface: FeatureQuery

Return true if has set constants attribute names

Specified by:

hasConstantsAttributeNames in interface FeatureQuery

Returns:

true if has constants attribute names, otherwise false

clearConstantsAttributeNames

public void clearConstantsAttributeNames()

Description copied from interface: FeatureQuery

Remove all the names specified as constants attributes.

Specified by:

clearConstantsAttributeNames in interface FeatureQuery