Class HashFunction

java.lang.Object

org.h2.expression.Expression

org.h2.expression.OperationN

org.h2.expression.function.FunctionN

org.h2.expression.function.HashFunction

All Implemented Interfaces:

ExpressionWithVariableParameters, NamedExpression, HasSQL, Typed

public final class HashFunction
extends FunctionN

A HASH or ORA_HASH function.

Field Summary

Fields

Modifier and Type	Field	Description
private final int	function
static final int	HASH	HASH() (non-standard).
private static final String[]	NAMES
static final int	ORA_HASH	ORA_HASH() (non-standard).

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
HashFunction(Expression arg, int function)
HashFunction(Expression arg1, Expression arg2, Expression arg3, int function)

Method Summary

Modifier and Type	Method	Description
private static Value	getHash(String algorithm, Value value, int iterations)
String	getName()	Get the name.
Value	getValue(SessionLocal session, Value v1, Value v2, Value v3)	Returns the value of this function.
private static MessageDigest	hashImpl(Value value, String algorithm)
private static MessageDigest	hashImpl(Value value, MessageDigest md)
Expression	optimize(SessionLocal session)	Try to optimize the expression.
private static Value	oraHash(Value value, long bucket, long seed)

Methods inherited from class FunctionN

getUnenclosedSQL, getValue

Methods inherited from class OperationN

addParameter, doneWithParameters, getCost, getSubexpression, getSubexpressionCount, getType, isEverything, 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, 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

HASH

public static final int HASH

HASH() (non-standard).

See Also:

• Constant Field Values

ORA_HASH

public static final int ORA_HASH

ORA_HASH() (non-standard).

See Also:

• Constant Field Values

NAMES

private static final String[] NAMES

function

private final int function

Constructor Details

HashFunction

public HashFunction(Expression arg,
 int function)

HashFunction

public HashFunction(Expression arg1,
 Expression arg2,
 Expression arg3,
 int function)

Method Details

getValue

public Value getValue(SessionLocal session,
 Value v1,
 Value v2,
 Value v3)

Description copied from class: FunctionN

Returns the value of this function.

Overrides:

getValue in class FunctionN

Parameters:

session - the session

v1 - the value of first argument, or null

v2 - the value of second argument, or null

v3 - the value of third argument, or null

Returns:

the resulting value

getHash

private static Value getHash(String algorithm,
 Value value,
 int iterations)

oraHash

private static Value oraHash(Value value,
 long bucket,
 long seed)

hashImpl

private static MessageDigest hashImpl(Value value,
 String algorithm)

hashImpl

private static MessageDigest hashImpl(Value value,
 MessageDigest md)

optimize

public Expression optimize(SessionLocal session)

Description copied from class: Expression

Try to optimize the expression.

Specified by:

optimize in class Expression

Parameters:

session - the session

Returns:

the optimized expression

getName

public String getName()

Description copied from interface: NamedExpression

Get the name.

Returns:

the name in uppercase