Class FunctionDef
- java.lang.Object
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- adql.db.FunctionDef
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- All Implemented Interfaces:
java.lang.Comparable<FunctionDef>
public class FunctionDef extends java.lang.Object implements java.lang.Comparable<FunctionDef>
Definition of any function that could be used in ADQL queries.
A such definition can be built manually thanks to the different constructors of this class, or by parsing a string function definition form using the static function
parse(String)
.The syntax of the expression expected by
parse(String)
is the same as the one used to build the string returned bytoString()
. Here is this syntax:{fctName}([{param1Name} {param1Type}, ...])[ -> {returnType}]
A description of this function may be set thanks to the public class attribute
description
.- Since:
- 1.3
- Version:
- 1.4 (08/2015)
- Author:
- Grégory Mantelet (ARI)
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
FunctionDef.FunctionParam
Definition of a function parameter.
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Field Summary
Fields Modifier and Type Field Description java.lang.String
description
Description of this function.protected static java.lang.String
fctDefRegExp
Rough regular expression for a whole function definition.protected static java.lang.String
fctParamRegExp
Rough regular expression for a function parameter: a name (seeregularIdentifierRegExp
) and a type (seetypeRegExp
).protected static java.lang.String
fctParamsRegExp
Rough regular expression for a function parameters' list.protected static java.util.regex.Pattern
fctPattern
Pattern of a function definition.protected boolean
isGeometry
Indicate whether the return type is a geometry.protected boolean
isNumeric
Indicate whether the return type is a numeric.protected boolean
isString
Indicate whether the return type is a string.protected boolean
isUnknown
Indicate whether the return type is an unknown type.java.lang.String
name
Name of the function.int
nbParams
Total number of parameters.protected static java.util.regex.Pattern
paramPattern
Pattern of a single parameter definition.protected FunctionDef.FunctionParam[]
params
List of all the parameters of this function.protected static java.lang.String
regularIdentifierRegExp
Regular expression for what should be a function or parameter name - a regular identifier.DBType
returnType
Type of the result returned by this function.protected static java.lang.String
typeRegExp
Rough regular expression for a function return type or a parameter type.
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Constructor Summary
Constructors Constructor Description FunctionDef(java.lang.String fctName)
Create a function definition.FunctionDef(java.lang.String fctName, DBType returnType)
Create a function definition.FunctionDef(java.lang.String fctName, DBType returnType, FunctionDef.FunctionParam[] params)
FunctionDef(java.lang.String fctName, FunctionDef.FunctionParam[] params)
Create a function definition.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description int
compareTo(FunctionDef def)
int
compareTo(ADQLFunction fct)
Compare this function definition with the given ADQL function item.int
getNbParams()
Get the number of parameters required by this function.FunctionDef.FunctionParam
getParam(int indParam)
Get the definition of the indParam-th parameter of this function.java.lang.Class<? extends UserDefinedFunction>
getUDFClass()
Get the class of theUserDefinedFunction
able to represent the function defined here in an ADQL tree.boolean
isGeometry()
Tell whether this function returns a geometry.boolean
isNumeric()
Tell whether this function returns a numeric.boolean
isString()
Tell whether this function returns a string.boolean
isUnknown()
Tell whether this function returns an unknown type.static FunctionDef
parse(java.lang.String strDefinition)
Let parsing the serialized form of a function definition.<T extends UserDefinedFunction>
voidsetUDFClass(java.lang.Class<T> udfClass)
Set the class of theUserDefinedFunction
able to represent the function defined here in an ADQL tree.java.lang.String
toString()
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Field Detail
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regularIdentifierRegExp
protected static final java.lang.String regularIdentifierRegExp
Regular expression for what should be a function or parameter name - a regular identifier.- See Also:
- Constant Field Values
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typeRegExp
protected static final java.lang.String typeRegExp
Rough regular expression for a function return type or a parameter type. The exact type is not checked here ; just the type name syntax is tested, not its value. This regular expression allows a type to have exactly one parameter (which is generally the length of a character or binary string.- See Also:
- Constant Field Values
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fctParamsRegExp
protected static final java.lang.String fctParamsRegExp
Rough regular expression for a function parameters' list.- See Also:
- Constant Field Values
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fctParamRegExp
protected static final java.lang.String fctParamRegExp
Rough regular expression for a function parameter: a name (seeregularIdentifierRegExp
) and a type (seetypeRegExp
).- See Also:
- Constant Field Values
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fctDefRegExp
protected static final java.lang.String fctDefRegExp
Rough regular expression for a whole function definition.- See Also:
- Constant Field Values
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fctPattern
protected static final java.util.regex.Pattern fctPattern
Pattern of a function definition. This object has been compiled withfctDefRegExp
.
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paramPattern
protected static final java.util.regex.Pattern paramPattern
Pattern of a single parameter definition. This object has been compiled withfctParamRegExp
.
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name
public final java.lang.String name
Name of the function.
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description
public java.lang.String description
Description of this function.
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returnType
public final DBType returnType
Type of the result returned by this function.
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isString
protected final boolean isString
Indicate whether the return type is a string.
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isNumeric
protected final boolean isNumeric
Indicate whether the return type is a numeric.
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isGeometry
protected final boolean isGeometry
Indicate whether the return type is a geometry.
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isUnknown
protected final boolean isUnknown
Indicate whether the return type is an unknown type.Note: If
true
,isString
,isNumeric
andisGeometry
arefalse
. Otherwise, at least one of these attributes is set totrue
.- Since:
- 1.4
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nbParams
public final int nbParams
Total number of parameters.
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params
protected final FunctionDef.FunctionParam[] params
List of all the parameters of this function.
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Constructor Detail
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FunctionDef
public FunctionDef(java.lang.String fctName)
Create a function definition.
The created function will have no return type and no parameter.
- Parameters:
fctName
- Name of the function.
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FunctionDef
public FunctionDef(java.lang.String fctName, DBType returnType)
Create a function definition.
The created function will have a return type (if the provided one is not null) and no parameter.
- Parameters:
fctName
- Name of the function.returnType
- Return type of the function. If NULL, this function will have no return type
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FunctionDef
public FunctionDef(java.lang.String fctName, FunctionDef.FunctionParam[] params)
Create a function definition.
The created function will have no return type and some parameters (except if the given array is NULL or empty).
- Parameters:
fctName
- Name of the function.params
- Parameters of this function. If NULL or empty, this function will have no parameter.
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FunctionDef
public FunctionDef(java.lang.String fctName, DBType returnType, FunctionDef.FunctionParam[] params)
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Method Detail
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isNumeric
public final boolean isNumeric()
Tell whether this function returns a numeric.- Returns:
- true if this function returns a numeric, false otherwise.
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isString
public final boolean isString()
Tell whether this function returns a string.- Returns:
- true if this function returns a string, false otherwise.
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isGeometry
public final boolean isGeometry()
Tell whether this function returns a geometry.- Returns:
- true if this function returns a geometry, false otherwise.
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isUnknown
public final boolean isUnknown()
Tell whether this function returns an unknown type.
If this function returns
true
,isNumeric()
,isString()
andisGeometry()
MUST ALL returnfalse
. Otherwise, one of these 3 last functions MUST returntrue
.- Returns:
- true if this function returns an unknown/unresolved/unsupported type, false otherwise.
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getNbParams
public final int getNbParams()
Get the number of parameters required by this function.- Returns:
- Number of required parameters.
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getParam
public final FunctionDef.FunctionParam getParam(int indParam) throws java.lang.ArrayIndexOutOfBoundsException
Get the definition of the indParam-th parameter of this function.- Parameters:
indParam
- Index of the parameter whose the definition must be returned.- Returns:
- Definition of the specified parameter.
- Throws:
java.lang.ArrayIndexOutOfBoundsException
- If the given index is negative or bigger than the number of parameters.
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getUDFClass
public final java.lang.Class<? extends UserDefinedFunction> getUDFClass()
Get the class of the
UserDefinedFunction
able to represent the function defined here in an ADQL tree.Note: This getter should return always NULL if the function defined here is not a user defined function.
However, if thisFunctionDef
is defining a user defined function and this function returns NULL, the library will create on the fly aDefaultUDF
corresponding to this definition when needed. Indeed this UDF class is useful only if the translation from ADQL (to SQL for instance) of the defined function has a different signature (e.g. a different name) in the target language (e.g. SQL).- Returns:
- The corresponding
UserDefinedFunction
. MAY BE NULL
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setUDFClass
public final <T extends UserDefinedFunction> void setUDFClass(java.lang.Class<T> udfClass) throws java.lang.IllegalArgumentException
Set the class of the
UserDefinedFunction
able to represent the function defined here in an ADQL tree.Note: If this
FunctionDef
defines an ordinary ADQL function - and not a user defined function - no class should be set here.
However, if it defines a user defined function, there is no obligation to set a UDF class. It is useful only if the translation from ADQL (to SQL for instance) of the function has a different signature (e.g. a different name) in the target language (e.g. SQL). If the signature is the same, there is no need to set a UDF class ; aDefaultUDF
will be created on the fly by the library when needed if it turns out that no UDF class is set.- Parameters:
udfClass
- Class to use to represent in an ADQL tree the User Defined Function defined in thisFunctionDef
.- Throws:
java.lang.IllegalArgumentException
- If the given class does not provide any constructor with a single parameter of type ADQLOperand[].
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parse
public static FunctionDef parse(java.lang.String strDefinition) throws ParseException
Let parsing the serialized form of a function definition.
The expected syntax is (items between brackets are optional):
{fctName}([{param1Name} {param1Type}, ...])[ -> {returnType}]
This function must be able to parse functions as defined by TAPRegExt (section 2.3). Hence, allowed parameter types and return types should be one of the types listed by the UPLOAD section of the TAP recommendation document. These types are listed in the enumeration object
DBType.DBDatatype
. However, other types should be accepted like the common database types...but it should be better to not rely on that since the conversion of those types to TAP types should not be exactly what is expected (because depending from the used DBMS); a default interpretation of database types is nevertheless processed by this parser.- Parameters:
strDefinition
- Serialized function definition to parse.- Returns:
- The object representation of the given string definition.
- Throws:
ParseException
- If the given string has a wrong syntax or uses unknown types.
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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compareTo
public int compareTo(FunctionDef def)
- Specified by:
compareTo
in interfacejava.lang.Comparable<FunctionDef>
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compareTo
public int compareTo(ADQLFunction fct)
Compare this function definition with the given ADQL function item.
The comparison is done only on the function name and on rough type of the parameters. "Rough type" means here that just the kind of type is tested: numeric, string or geometry. Anyway, the return type is never tested by this function, since such information is usually not part of a function signature.
The notions of "greater" and "less" are defined here according to the three following test steps:
- Name test: if the name of both function are equals, next steps are evaluated, otherwise the standard string comparison (case insensitive) result is returned.
- Parameters test: parameters are compared individually. Each time parameters (at the same position in both functions) are equals the next parameter can be tested, and so on until two parameters are different or the end of the parameters' list is reached. Just the kind of type is used for parameter comparison. Each kind of type is tested in the following order: numeric, string and geometry. When a kind of type is not equal for both parameters, the function exits with the appropriate value (1 if the parameter of this function definition is of the kind of type, -1 otherwise).
- Number of parameters test: in the case where this function definition has N parameters and the given ADQL function has M parameters, and that the L (= min(N,M)) first parameters have the same type in both functions, the value returns by this function will be N-M. Thus, if this function definition has more parameters than the given function, a positive value will be returned. Otherwise a negative value will be returned, or 0 if the number of parameters is the same.
Note: If one of the tested types (i.e. parameters types) is unknown, the match should return 0 (i.e. equality). The notion of "unknown" is different in function of the tested item. A
DBType
is unknown if its functionDBType.isUnknown()
returnstrue
; thus, its other functions such asDBType.isNumeric()
will returnfalse
. On the contrary, anADQLOperand
does not have any isUnknown() function. However, when the type of a such is unknown, all its functions isNumeric(), isString() and isGeometry() returntrue
.- Parameters:
fct
- ADQL function item to compare with this function definition.- Returns:
- A positive value if this function definition is "greater" than the given
ADQLFunction
, 0 if they are perfectly matching or one of the tested types (i.e. parameters types) is unknown, or a negative value if this function definition is "less" than the givenADQLFunction
.
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