org.h2.expression.condition

Class NullPredicate

java.lang.Object

org.h2.expression.Expression

org.h2.expression.condition.SimplePredicate

org.h2.expression.condition.NullPredicate

All Implemented Interfaces:

HasSQL, Typed

public final class NullPredicate
extends SimplePredicate

Null predicate (IS [NOT] NULL).

Field Summary

Fields inherited from class org.h2.expression.Expression

AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES

Fields inherited from interface org.h2.util.HasSQL

ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

Constructor Summary

Constructors

Constructor and Description
NullPredicate(Expression left, boolean not, boolean whenOperand)

Method Summary

Modifier and Type	Method and Description
void	createIndexConditions(SessionLocal session, TableFilter filter) Create index conditions if possible and attach them to the table filter.
Expression	getNotIfPossible(SessionLocal session) If it is possible, return the negated expression.
TypeInfo	getType() Returns the data type.
java.lang.StringBuilder	getUnenclosedSQL(java.lang.StringBuilder builder, int sqlFlags) Get the SQL statement of this expression.
Value	getValue(SessionLocal session) Return the resulting value for the current row.
java.lang.StringBuilder	getWhenSQL(java.lang.StringBuilder builder, int sqlFlags) Appends the SQL statement of this when operand to the specified builder.
boolean	getWhenValue(SessionLocal session, Value left) Return the resulting value of when operand for the current row.
Expression	optimize(SessionLocal session) Try to optimize the expression.

Methods inherited from class org.h2.expression.condition.SimplePredicate

getCost, getSubexpression, getSubexpressionCount, isEverything, isWhenConditionOperand, mapColumns, needParentheses, setEvaluatable, updateAggregate

Methods inherited from class org.h2.expression.Expression

addFilterConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, isConstant, isIdentity, isNullConstant, isValueSet, optimizeCondition, toString, writeExpressions, writeExpressions

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.util.HasSQL

getTraceSQL

Constructor Detail

NullPredicate

public NullPredicate(Expression left,
                     boolean not,
                     boolean whenOperand)

Method Detail

getUnenclosedSQL

public java.lang.StringBuilder getUnenclosedSQL(java.lang.StringBuilder builder,
                                                int sqlFlags)

Description copied from class: Expression

Get the SQL statement of this expression. This may not always be the original SQL statement, especially after optimization. Enclosing '(' and ')' are never appended.

Specified by:

getUnenclosedSQL in class Expression

Parameters:

builder - string builder

sqlFlags - formatting flags

Returns:

the specified string builder

getWhenSQL

public java.lang.StringBuilder getWhenSQL(java.lang.StringBuilder builder,
                                          int sqlFlags)

Description copied from class: Expression

Appends the SQL statement of this when operand to the specified builder.

Overrides:

getWhenSQL in class Expression

Parameters:

builder - string builder

sqlFlags - formatting flags

Returns:

the specified string builder

optimize

public Expression optimize(SessionLocal session)

Description copied from class: Expression

Try to optimize the expression.

Overrides:

optimize in class SimplePredicate

Parameters:

session - the session

Returns:

the optimized expression

getValue

public Value getValue(SessionLocal session)

Description copied from class: Expression

Return the resulting value for the current row.

Specified by:

getValue in class Expression

Parameters:

session - the session

Returns:

the result

getWhenValue

public boolean getWhenValue(SessionLocal session,
                            Value left)

Description copied from class: Expression

Return the resulting value of when operand for the current row.

Overrides:

getWhenValue in class Expression

Parameters:

session - the session

left - value on the left side

Returns:

the result

getNotIfPossible

public Expression getNotIfPossible(SessionLocal session)

Description copied from class: Expression

If it is possible, return the negated expression. This is used to optimize NOT expressions: NOT ID>10 can be converted to ID<=10. Returns null if negating is not possible.

Overrides:

getNotIfPossible in class Expression

Parameters:

session - the session

Returns:

the negated expression, or null

createIndexConditions

public void createIndexConditions(SessionLocal session,
                                  TableFilter filter)

Description copied from class: Expression

Create index conditions if possible and attach them to the table filter.

Overrides:

createIndexConditions in class Expression

Parameters:

session - the session

filter - the table filter

getType

public TypeInfo getType()

Description copied from class: Expression

Returns the data type. The data type may be unknown before the optimization phase.

Specified by:

getType in interface Typed

Specified by:

getType in class Expression

Returns:

the data type