Class PolygonFunction
- All Implemented Interfaces:
ADQLObject
,ADQLOperand
This function expresses a region on the sky with boundaries denoted by great circles passing through specified vertices. It corresponds semantically to the STC Polygon.
A polygon is described by a list of vertices in a single coordinate system, with each vertex connected to the next along a great circle and the last vertex implicitly connected to the first vertex.
The function arguments specify three or more vertices, where:
- the position of the vertices are given as a sequence of numeric coordinates in degrees, or as a sequence of geometric POINTs
- the numeric coordinates MUST be within the ranges [0,360] and [-90,90]
Example:
A function expressing a triangle, whose vertices are (10.0, -10.5), (20.0, 20.5) and (30.0,30.5) in degrees would be written as follows:
POLYGON(10.0, -10.5, 20.0, 20.5, 30.0, 30.5)
, where all numeric values are in degrees.
or alternatively as follows:
POLYGON(POINT(10.0, -10.5), POINT(20.0, 20.5), POINT(30.0, 30.5))
The coordinates for the POLYGON vertices may be literal values, as above, or they may be column references, functions or expressions that return numeric values.
Example:
POLYGON(t1.ra, t1.dec + 5, t1.ra - 5, t1.dec - 5, t1.ra - 5, t1.dec + 5)
, where t1.ra and t1.dec are references to database columns that contain numeric values.
Alternatively, the coordinates for the POLYGON vertices may be column references, functions or expressions that return POINT values.
Example:
POLYGON(t2.toppoint, t2.bottomleft, t2.bottomright)
, where t2.toppoint, t2.bottomleft and t2.bottomright are references to database columns that contain POINT values.
The coordinates for the vertices MUST all be expressed in the same datatype. The POLYGON function does not support a mixture of numeric and POINT arguments.
For historical reasons, the POLYGON function accepts an optional string value as the first argument. As of this version of the specification (2.1) this parameter has been marked as deprecated. Future versions of this specification (> 2.1) may remove this parameter.
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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 TypeFieldDescriptionprotected Vector<ADQLOperand>
The vertices.static final LanguageFeature
Description of this ADQL Feature.Fields inherited from class adql.query.operand.function.geometry.GeometryFunction
coordSys
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Constructor Summary
ConstructorsConstructorDescriptionPolygonFunction
(ADQLOperand coordSystem, ADQLOperand[] coords) Builds a polygon function with at least 3 2-D coordinates (that is to say, the array must contain at least 6 operands).PolygonFunction
(ADQLOperand coordSystem, Collection<? extends ADQLOperand> coords) Builds a polygon function with at least: 3 pairs of coordinates (that is to say, the vector must contain at least 6 items), OR 3 point values (so, a vector containing at least 3 items).PolygonFunction
(PolygonFunction toCopy) Builds a POLYGON function by copying the given one. -
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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coordinates
The vertices.
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Constructor Details
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PolygonFunction
public PolygonFunction(ADQLOperand coordSystem, ADQLOperand[] coords) throws UnsupportedOperationException, NullPointerException, Exception Builds a polygon function with at least 3 2-D coordinates (that is to say, the array must contain at least 6 operands).- Parameters:
coordSystem
- A string operand which corresponds to a valid coordinate system.coords
- An array of at least 3 2-D coordinates (length>=6).- Throws:
UnsupportedOperationException
- If this function is not associated with a coordinate system.NullPointerException
- If one of the parameters is NULL.Exception
- If there is another error.
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PolygonFunction
public PolygonFunction(ADQLOperand coordSystem, Collection<? extends ADQLOperand> coords) throws UnsupportedOperationException, NullPointerException, Exception Builds a polygon function with at least:- 3 pairs of coordinates (that is to say, the vector must contain at least 6 items),
- OR 3 point values (so, a vector containing at least 3 items).
- Parameters:
coordSystem
- A string operand which corresponds to a valid coordinate system.coords
- A vector of at least 3 vertices.- Throws:
UnsupportedOperationException
- If this function is not associated with a coordinate system.NullPointerException
- If one of the parameters is NULL.Exception
- If there is another error.
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PolygonFunction
Builds a POLYGON function by copying the given one.- Parameters:
toCopy
- The POLYGON 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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