org.teiid.query.function
Class FunctionLibrary

java.lang.Object
  org.teiid.query.function.FunctionLibrary

public class FunctionLibrary
extends Object

The function library is the primary way for the system to find out what functions are available, resolve function signatures, and invoke system and user-defined functions.

Field Summary

static String	CAST
static String	COALESCE
static String	COMMAND_PAYLOAD
static String	CONCAT
static String	CONCAT_OPERATOR
static String	CONCAT2
static String	CONTEXT
static String	CONVERT
static String	DECODEINTEGER
static String	DECODESTRING
static String	ENV
static String	FORMATDATE
static String	FORMATTIME
static String	FROM_UNIXTIME
static String	IFNULL
static String	LOOKUP
static String	NULLIF
static String	NVL
static String	PARSEDATE
static String	PARSETIME
static String	ROWLIMIT
static String	ROWLIMITEXCEPTION
static String	SESSION_ID
static String	SPACE
static String	SUBSTRING
static String	TIMESTAMPADD
static String	USER

Constructor Summary

FunctionLibrary(FunctionTree systemFuncs, FunctionTree... userFuncs)
Construct the function library.

Method Summary

FunctionDescriptor	copyFunctionChangeReturnType(FunctionDescriptor fd, Class<?> returnType) Return a copy of the given FunctionDescriptor with the sepcified return type.
FunctionDescriptor[]	determineNecessaryConversions(String name, Class<?> returnType, Class<?>[] types, boolean hasUnknownType) Get the conversions that are needed to call the named function with arguments of the given type.
FunctionDescriptor	findFunction(String name, Class<?>[] types) Find a function descriptor given a name and the types of the arguments.
FunctionForm	findFunctionForm(String name, int numArgs) Find function form based on function name and # of arguments.
FunctionDescriptor	findTypedConversionFunction(Class<?> sourceType, Class<?> targetType) Find conversion function and set return type to proper type.
List<String>	getFunctionCategories() Get all function categories, sorted in alphabetical order
List<FunctionForm>	getFunctionForms(String category) Get all function forms in a category, sorted by name, then # of args, then names of args.
static boolean	isConvert(Function function)

Methods inherited from class java.lang.Object

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

Field Detail

CONVERT

public static final String CONVERT

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Constant Field Values

CAST

public static final String CAST

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Constant Field Values

LOOKUP

public static final String LOOKUP

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Constant Field Values

USER

public static final String USER

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Constant Field Values

ENV

public static final String ENV

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Constant Field Values

SESSION_ID

public static final String SESSION_ID

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Constant Field Values

CONTEXT

public static final String CONTEXT

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Constant Field Values

ROWLIMIT

public static final String ROWLIMIT

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Constant Field Values

ROWLIMITEXCEPTION

public static final String ROWLIMITEXCEPTION

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Constant Field Values

DECODESTRING

public static final String DECODESTRING

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Constant Field Values

DECODEINTEGER

public static final String DECODEINTEGER

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Constant Field Values

COMMAND_PAYLOAD

public static final String COMMAND_PAYLOAD

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Constant Field Values

CONCAT

public static final String CONCAT

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Constant Field Values

CONCAT2

public static final String CONCAT2

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Constant Field Values

CONCAT_OPERATOR

public static final String CONCAT_OPERATOR

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Constant Field Values

SUBSTRING

public static final String SUBSTRING

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Constant Field Values

NVL

public static final String NVL

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Constant Field Values

IFNULL

public static final String IFNULL

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Constant Field Values

FROM_UNIXTIME

public static final String FROM_UNIXTIME

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Constant Field Values

TIMESTAMPADD

public static final String TIMESTAMPADD

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Constant Field Values

PARSETIME

public static final String PARSETIME

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Constant Field Values

PARSEDATE

public static final String PARSEDATE

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Constant Field Values

FORMATTIME

public static final String FORMATTIME

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Constant Field Values

FORMATDATE

public static final String FORMATDATE

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Constant Field Values

NULLIF

public static final String NULLIF

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Constant Field Values

COALESCE

public static final String COALESCE

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Constant Field Values

SPACE

public static final String SPACE

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Constant Field Values

Constructor Detail

FunctionLibrary

public FunctionLibrary(FunctionTree systemFuncs,
                       FunctionTree... userFuncs)

Construct the function library. This should be called only once by the FunctionLibraryManager.

Method Detail

getFunctionCategories

public List<String> getFunctionCategories()

Get all function categories, sorted in alphabetical order

Returns:

List of function category names, sorted in alphabetical order

getFunctionForms

public List<FunctionForm> getFunctionForms(String category)

Get all function forms in a category, sorted by name, then # of args, then names of args.

Parameters:

category - Category name

Returns:

List of FunctionForms in a category

findFunctionForm

public FunctionForm findFunctionForm(String name,
                                     int numArgs)

Find function form based on function name and # of arguments.

Parameters:

name - Function name

numArgs - Number of arguments

Returns:

Corresponding form or null if not found

findFunction

public FunctionDescriptor findFunction(String name,
                                       Class<?>[] types)

Find a function descriptor given a name and the types of the arguments. This method matches based on case-insensitive function name and an exact match of the number and types of parameter arguments.

Parameters:

name - Name of the function to resolve

types - Array of classes representing the types

Returns:

Descriptor if found, null if not found

determineNecessaryConversions

public FunctionDescriptor[] determineNecessaryConversions(String name,
                                                          Class<?> returnType,
                                                          Class<?>[] types,
                                                          boolean hasUnknownType)

Get the conversions that are needed to call the named function with arguments of the given type. In the case of an exact match, the list will contain all nulls. In other cases the list will contain one or more non-null values where the value is a conversion function that can be used to convert to the proper types for executing the function.

Parameters:

name - Name of function

returnType -

types - Existing types passed to the function

Returns:

Null if no conversion could be found, otherwise an array of conversions to apply to each argument. The list should match 1-to-1 with the parameters. Parameters that do not need a conversion are null; parameters that do are FunctionDescriptors.

Throws:

QueryResolverException

findTypedConversionFunction

public FunctionDescriptor findTypedConversionFunction(Class<?> sourceType,
                                                      Class<?> targetType)

Find conversion function and set return type to proper type.

Parameters:

sourceType - The source type class

targetType - The target type class

Returns:

A CONVERT function descriptor or null if not possible

copyFunctionChangeReturnType

public FunctionDescriptor copyFunctionChangeReturnType(FunctionDescriptor fd,
                                                       Class<?> returnType)

Return a copy of the given FunctionDescriptor with the sepcified return type.

Parameters:

fd - FunctionDescriptor to be copied.

returnType - The return type to apply to the copied FunctionDescriptor.

Returns:

The copy of FunctionDescriptor.

isConvert

public static boolean isConvert(Function function)