org.d2rq.db.expr
Class Equality
java.lang.Object
org.d2rq.db.expr.Expression
org.d2rq.db.expr.BinaryOperator
org.d2rq.db.expr.Equality
public class Equality
- extends BinaryOperator
An expression that is TRUE iff its two constituent expressions are true.
- Author:
- Richard Cyganiak (richard@cyganiak.de)
Method Summary |
static Expression |
create(Expression expr1,
Expression expr2)
|
static Expression |
createColumnEquality(ColumnName column1,
ColumnName column2)
|
static Expression |
createColumnValue(ColumnName column,
String value,
DataType dataType)
|
static Expression |
createExpressionValue(Expression expression,
String value,
DataType dataType)
|
boolean |
isConstantColumn(ColumnName column,
boolean constIfTrue,
boolean constIfFalse,
boolean constIfConstantValue)
Checks whether this expression forces a given column to be a constant,
that is, have the same value everywhere. |
boolean |
isFalse()
|
boolean |
isTrue()
|
Expression |
rename(Renamer columnRenamer)
|
create
public static Expression create(Expression expr1,
Expression expr2)
createColumnEquality
public static Expression createColumnEquality(ColumnName column1,
ColumnName column2)
createColumnValue
public static Expression createColumnValue(ColumnName column,
String value,
DataType dataType)
createExpressionValue
public static Expression createExpressionValue(Expression expression,
String value,
DataType dataType)
isFalse
public boolean isFalse()
- Overrides:
isFalse
in class BinaryOperator
isTrue
public boolean isTrue()
- Overrides:
isTrue
in class BinaryOperator
isConstantColumn
public boolean isConstantColumn(ColumnName column,
boolean constIfTrue,
boolean constIfFalse,
boolean constIfConstantValue)
- Description copied from class:
Expression
- Checks whether this expression forces a given column to be a constant,
that is, have the same value everywhere. For example,
T.COL1=5 forces T.COL1 to be constant if the expression is assumed
to be true; T.COL1+1 forces it to be constant if the expression
is assumed to evaluate to a constant value. Exactly one of the three
constXXX arguments must be true, the other two must be false.
- Overrides:
isConstantColumn
in class BinaryOperator
- Parameters:
column
- The column to be checkedconstIfTrue
- Is the column constant assuming the expression evaluates to true?constIfFalse
- Is the column constant assuming the expression evaluates to false?constIfConstantValue
- Is column constant assuming the expression evaluates to a value equal to some constant?
rename
public Expression rename(Renamer columnRenamer)
- Specified by:
rename
in class Expression