FunctionDef

java.lang.Object
- adql.db.FunctionDef

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 by toString(). 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)

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class FunctionDef.FunctionParam
Definition of a function parameter.

Nested Classes
Modifier and Type	Class and Description
`static class`	`FunctionDef.FunctionParam` Definition of a function parameter.

Field Summary

Fields
Modifier and Type	Field and 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 (see `regularIdentifierRegExp`) and a type (see `typeRegExp`).
`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.

Constructor Summary

Constructors
Constructor and 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.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`compareTo(ADQLFunction fct)` Compare this function definition with the given ADQL function item.
`int`	`compareTo(FunctionDef def)`
`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 the `UserDefinedFunction` 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> void`	`setUDFClass(java.lang.Class<T> udfClass)` Set the class of the `UserDefinedFunction` able to represent the function defined here in an ADQL tree.
`java.lang.String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - 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
  - 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
  - fctParamsRegExp
```
protected static final java.lang.String fctParamsRegExp
```
    Rough regular expression for a function parameters' list.
    
    See Also:
    
    Constant Field Values
  - fctParamRegExp
```
protected static final java.lang.String fctParamRegExp
```
    Rough regular expression for a function parameter: a name (see regularIdentifierRegExp) and a type (see typeRegExp).
    
    See Also:
    
    Constant Field Values
  - fctDefRegExp
```
protected static final java.lang.String fctDefRegExp
```
    Rough regular expression for a whole function definition.
    
    See Also:
    
    Constant Field Values
  - fctPattern
```
protected static final java.util.regex.Pattern fctPattern
```
    Pattern of a function definition. This object has been compiled with fctDefRegExp.
  - paramPattern
```
protected static final java.util.regex.Pattern paramPattern
```
    Pattern of a single parameter definition. This object has been compiled with fctParamRegExp.
  - name
```
public final java.lang.String name
```
    Name of the function.
  - description
```
public java.lang.String description
```
    Description of this function.
  - returnType
```
public final DBType returnType
```
    Type of the result returned by this function.
  - isString
```
protected final boolean isString
```
    Indicate whether the return type is a string.
  - isNumeric
```
protected final boolean isNumeric
```
    Indicate whether the return type is a numeric.
  - isGeometry
```
protected final boolean isGeometry
```
    Indicate whether the return type is a geometry.
  - isUnknown
```
protected final boolean isUnknown
```
    Indicate whether the return type is an unknown type.
    Note: If true, isString, isNumeric and isGeometry are false. Otherwise, at least one of these attributes is set to true.
    
    Since:
    
    1.4
  - nbParams
```
public final int nbParams
```
    Total number of parameters.
  - params
```
protected final FunctionDef.FunctionParam[] params
```
    List of all the parameters of this function.
- Constructor Detail
  - 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.
  - 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
  - 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.
  - FunctionDef
```
public FunctionDef(java.lang.String fctName,
                   DBType returnType,
                   FunctionDef.FunctionParam[] params)
```
- Method Detail
  - isNumeric
```
public final boolean isNumeric()
```
    Tell whether this function returns a numeric.
    
    Returns:
    
    true if this function returns a numeric, false otherwise.
  - isString
```
public final boolean isString()
```
    Tell whether this function returns a string.
    
    Returns:
    
    true if this function returns a string, false otherwise.
  - isGeometry
```
public final boolean isGeometry()
```
    Tell whether this function returns a geometry.
    
    Returns:
    
    true if this function returns a geometry, false otherwise.
  - isUnknown
```
public final boolean isUnknown()
```
    Tell whether this function returns an unknown type.
    
    If this function returns true, isNumeric(), isString() and isGeometry() MUST ALL return false. Otherwise, one of these 3 last functions MUST return true.
    
    Returns:
    
    true if this function returns an unknown/unresolved/unsupported type, false otherwise.
  - getNbParams
```
public final int getNbParams()
```
    Get the number of parameters required by this function.
    
    Returns:
    
    Number of required parameters.
  - 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.
  - 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 this FunctionDef is defining a user defined function and this function returns NULL, the library will create on the fly a DefaultUDF 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
  - 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 ; a DefaultUDF 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 this FunctionDef.
    
    Throws:
    
    java.lang.IllegalArgumentException - If the given class does not provide any constructor with a single parameter of type ADQLOperand[].
  - 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.
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - compareTo
```
public int compareTo(FunctionDef def)
```
    Specified by:
    
    compareTo in interface java.lang.Comparable<FunctionDef>
  - 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:
    1. Name test: if the name of both function are equals, next steps are evaluated, otherwise the standard string comparison (case insensitive) result is returned.
    2. 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).
    3. 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 function DBType.isUnknown() returns true ; thus, its other functions such as DBType.isNumeric() will return false. On the contrary, an ADQLOperand does not have any isUnknown() function. However, when the type of a such is unknown, all its functions isNumeric(), isString() and isGeometry() return true.
    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 given ADQLFunction.

Class FunctionDef

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

regularIdentifierRegExp

typeRegExp

fctParamsRegExp

fctParamRegExp

fctDefRegExp

fctPattern

paramPattern

name

description

returnType

isString

isNumeric

isGeometry

isUnknown

nbParams

params

Constructor Detail

FunctionDef

FunctionDef

FunctionDef

FunctionDef

Method Detail

isNumeric

isString

isGeometry

isUnknown

getNbParams

getParam

getUDFClass

setUDFClass

parse

toString

compareTo

compareTo