Class CentroidFunction
java.lang.Object
adql.query.operand.function.ADQLFunction
adql.query.operand.function.geometry.GeometryFunction
adql.query.operand.function.geometry.CentroidFunction
- All Implemented Interfaces:
ADQLObject
,ADQLOperand
It represents the CENTROID function of the ADQL language.
This function computes the centroid of a given geometry and returns a POINT.
Example:
An expression to calculate the centroid of a POLYGON could be written as follows :
CENTROID(POLYGON(10.0, -10.5, 20.0, 20.5, 30.0, 30.5))
The CENTROID of a single POINT is that POINT.
The geometry argument may be a literal value, as above, or it may be a column reference, function or expression that returns a geometric type.
Example:
CENTROID(t1.footprint)
, where t1.footprint is a reference to a database column that contains geometric (POINT, BOX, CIRCLE, POLYGON or REGION) values.
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Nested Class Summary
Nested classes/interfaces inherited from class adql.query.operand.function.geometry.GeometryFunction
GeometryFunction.GeometryValue<F extends GeometryFunction>
Nested classes/interfaces inherited from class adql.query.operand.function.ADQLFunction
ADQLFunction.ParameterIterator
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final LanguageFeature
Description of this ADQL Feature.protected GeometryFunction.GeometryValue<GeometryFunction>
The geometry whose the centroid must be extracted.Fields inherited from class adql.query.operand.function.geometry.GeometryFunction
coordSys
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Constructor Summary
ConstructorsConstructorDescriptionCentroidFunction
(CentroidFunction toCopy) Builds a CENTROID function by copying the given one.Builds a CENTROID function. -
Method Summary
Modifier and TypeMethodDescriptiongetCopy()
Gets a (deep) copy of this ADQL object.final LanguageFeature
Get the description of this ADQL's Language Feature.getName()
Gets the name of this object in ADQL.int
Gets the number of parameters this function has.getParameter
(int index) Gets the index-th parameter.Gets the list of all parameters of this function.boolean
Tell whether this operand is a geometrical region or not.boolean
Tell whether this operand is numeric or not.boolean
isString()
Tell whether this operand is a string or not.setParameter
(int index, ADQLOperand replacer) Replaces the index-th parameter by the given one.Methods inherited from class adql.query.operand.function.geometry.GeometryFunction
getCoordinateSystem, setCoordinateSystem
Methods inherited from class adql.query.operand.function.ADQLFunction
adqlIterator, getPosition, paramIterator, setPosition, toADQL
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Field Details
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FEATURE
Description of this ADQL Feature.- Since:
- 2.0
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parameter
The geometry whose the centroid must be extracted.
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Constructor Details
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CentroidFunction
public CentroidFunction(GeometryFunction.GeometryValue<GeometryFunction> param) throws NullPointerException Builds a CENTROID function.- Parameters:
param
- The geometry whose the centroid must be extracted.- Throws:
NullPointerException
- If the given parameter is NULL.
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CentroidFunction
Builds a CENTROID function by copying the given one.- Parameters:
toCopy
- The CENTROID function to copy.- Throws:
Exception
- If there is an error during the copy.
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Method Details
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getFeatureDescription
Description copied from interface:ADQLObject
Get the description of this ADQL's Language Feature.Note: Getting this description is generally only useful when discovery optional features so that determining if they are allowed to be used in ADQL queries.
- Returns:
- Description of this ADQL object as an ADQL's feature.
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getCopy
Description copied from interface:ADQLObject
Gets a (deep) copy of this ADQL object.- Returns:
- The copy of this ADQL object.
- Throws:
Exception
- If there is any error during the copy.
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getName
Description copied from interface:ADQLObject
Gets the name of this object in ADQL.- Returns:
- The name of this ADQL object.
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isNumeric
public boolean isNumeric()Description copied from interface:ADQLOperand
Tell whether this operand is numeric or not.- Returns:
- true if this operand is numeric, false otherwise.
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isString
public boolean isString()Description copied from interface:ADQLOperand
Tell whether this operand is a string or not.- Returns:
- true if this operand is a string, false otherwise.
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isGeometry
public boolean isGeometry()Description copied from interface:ADQLOperand
Tell whether this operand is a geometrical region or not.- Returns:
- true if this operand is a geometry, false otherwise.
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getParameters
Description copied from class:ADQLFunction
Gets the list of all parameters of this function.- Specified by:
getParameters
in classADQLFunction
- Returns:
- Its parameters list.
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getNbParameters
public int getNbParameters()Description copied from class:ADQLFunction
Gets the number of parameters this function has.- Specified by:
getNbParameters
in classADQLFunction
- Returns:
- Number of parameters.
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getParameter
Description copied from class:ADQLFunction
Gets the index-th parameter.- Specified by:
getParameter
in classADQLFunction
- Parameters:
index
- Parameter number.- Returns:
- The corresponding parameter.
- Throws:
ArrayIndexOutOfBoundsException
- If the index is incorrect (index < 0 || index >= getNbParameters()).
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setParameter
public ADQLOperand setParameter(int index, ADQLOperand replacer) throws ArrayIndexOutOfBoundsException, NullPointerException, Exception Description copied from class:ADQLFunction
Replaces the index-th parameter by the given one.- Specified by:
setParameter
in classADQLFunction
- Parameters:
index
- Index of the parameter to replace.replacer
- The replacer.- Returns:
- The replaced parameter.
- Throws:
ArrayIndexOutOfBoundsException
- If the index is incorrect (index < 0 || index >= getNbParameters()).NullPointerException
- If a required parameter must be replaced by a NULL object.Exception
- If another error occurs.
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