Class ModeFunction

java.lang.Object

org.h2.expression.Expression

org.h2.expression.OperationN

org.h2.expression.function.FunctionN

org.h2.mode.ModeFunction

All Implemented Interfaces:

ExpressionWithVariableParameters, NamedExpression, HasSQL, Typed

Direct Known Subclasses:

FunctionsDB2Derby, FunctionsLegacy, FunctionsMSSQLServer, FunctionsMySQL, FunctionsOracle, FunctionsPostgreSQL

public abstract class ModeFunction
extends FunctionN

Base class for mode-specific functions.

Field Summary

Fields

Modifier and Type	Field	Description
protected final FunctionInfo	info	The information about this function.
protected static final int	VAR_ARGS	Constant for variable number of arguments.

Fields inherited from class OperationN

args, argsCount, type

Fields inherited from class Expression

AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES

Fields inherited from interface HasSQL

ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

Constructor Summary

Constructors

Constructor	Description
ModeFunction(FunctionInfo info)	Creates a new instance of function.

Method Summary

Modifier and Type	Method	Description
(package private) void	checkParameterCount(int len)	Check if the parameter count is correct.
void	doneWithParameters()	This method must be called after all the parameters have been set.
(package private) final Value[]	getArgumentsValues(SessionLocal session, Expression[] args)	Gets values of arguments and checks them for NULL values if function returns NULL on NULL argument.
private static ModeFunction	getCompatibilityModeFunction(String name, Mode.ModeEnum modeEnum)
static ModeFunction	getFunction(Database database, String name)	Get an instance of the given function for this database.
String	getName()	Get the name.
(package private) static Value	getNullOrValue(SessionLocal session, Expression[] args, Value[] values, int i)	Get value transformed by expression, or null if i is out of range or the input value is null.
boolean	isEverything(ExpressionVisitor visitor)	Check if this expression and all sub-expressions can fulfill a criteria.
(package private) final boolean	optimizeArguments(SessionLocal session)	Optimizes arguments.

Methods inherited from class FunctionN

getUnenclosedSQL, getValue, getValue

Methods inherited from class OperationN

addParameter, getCost, getSubexpression, getSubexpressionCount, getType, mapColumns, optimizeArguments, setEvaluatable, updateAggregate

Methods inherited from class Expression

addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, optimize, optimizeCondition, toString, writeExpressions, writeExpressions

Methods inherited from class Object

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

Methods inherited from interface HasSQL

getTraceSQL

Field Details

VAR_ARGS

protected static final int VAR_ARGS

Constant for variable number of arguments.

See Also:

• Constant Field Values

info

protected final FunctionInfo info

The information about this function.

Constructor Details

ModeFunction

ModeFunction(FunctionInfo info)

Creates a new instance of function.

Parameters:

info - function information

Method Details

getFunction

public static ModeFunction getFunction(Database database,
 String name)

Get an instance of the given function for this database. If no function with this name is found, null is returned.

Parameters:

database - the database

name - the upper case function name

Returns:

the function object or null

getCompatibilityModeFunction

private static ModeFunction getCompatibilityModeFunction(String name,
 Mode.ModeEnum modeEnum)

getNullOrValue

static Value getNullOrValue(SessionLocal session,
 Expression[] args,
 Value[] values,
 int i)

Get value transformed by expression, or null if i is out of range or the input value is null.

Parameters:

session - database session

args - expressions

values - array of input values

i - index of value of transform

Returns:

value or null

getArgumentsValues

final Value[] getArgumentsValues(SessionLocal session,
 Expression[] args)

Gets values of arguments and checks them for NULL values if function returns NULL on NULL argument.

Parameters:

session - the session

args - the arguments

Returns:

the values, or null if function should return NULL due to NULL argument

checkParameterCount

void checkParameterCount(int len)

Check if the parameter count is correct.

Parameters:

len - the number of parameters set

Throws:

DbException - if the parameter count is incorrect

doneWithParameters

public void doneWithParameters()

Description copied from interface: ExpressionWithVariableParameters

This method must be called after all the parameters have been set. It checks if the parameter count is correct when required by the implementation.

Specified by:

doneWithParameters in interface ExpressionWithVariableParameters

Overrides:

doneWithParameters in class OperationN

optimizeArguments

final boolean optimizeArguments(SessionLocal session)

Optimizes arguments.

Parameters:

session - the session

Returns:

whether all arguments are constants and function is deterministic

getName

public String getName()

Description copied from interface: NamedExpression

Get the name.

Returns:

the name in uppercase

isEverything

public boolean isEverything(ExpressionVisitor visitor)

Description copied from class: Expression

Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.

Overrides:

isEverything in class OperationN

Parameters:

visitor - the visitor

Returns:

if the criteria can be fulfilled