org.h2.expression
Class Parameter

java.lang.Object
  extended by org.h2.expression.Expression
      extended by org.h2.expression.Parameter
All Implemented Interfaces:
ParameterInterface

public class Parameter
extends Expression
implements ParameterInterface

A parameter of a prepared statement.


Constructor Summary
Parameter(int index)
           
 
Method Summary
 void checkSet()
          Check if the value is set.
 int getCost()
          Estimate the cost to process the expression.
 int getDisplaySize()
          Get the display size of this expression.
 int getIndex()
           
 Expression getNotIfPossible(Session session)
          If it is possible, return the negated expression.
 Value getParamValue()
          Get the value of the parameter if set.
 long getPrecision()
          Get the precision of this expression.
 int getScale()
          Get the scale of this expression.
 java.lang.String getSQL()
          Get the SQL statement of this expression.
 int getType()
          Return the data type.
 Value getValue(Session session)
          Return the resulting value for the current row.
 boolean isConstant()
          Check if this expression will always return the same value.
 boolean isEverything(ExpressionVisitor visitor)
          Check if this expression and all sub-expressions can fulfill a criteria.
 boolean isValueSet()
          Is the value of a parameter set.
 void mapColumns(ColumnResolver resolver, int level)
          Map the columns of the resolver to expression columns.
 Expression optimize(Session session)
          Try to optimize the expression.
 void setColumn(Column column)
           
 void setEvaluatable(TableFilter tableFilter, boolean b)
          Tell the expression columns whether the table filter can return values now.
 void setValue(Value v)
           
 void setValue(Value v, boolean closeOld)
          Set the value of the parameter.
 void updateAggregate(Session session)
          Update an aggregate value.
 
Methods inherited from class org.h2.expression.Expression
addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getNonAliasExpression, getNullable, getSchemaName, getTableAlias, getTableName, isAutoIncrement, isEverything, isWildcard, optimizeInJoin, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.h2.expression.ParameterInterface
getNullable
 

Constructor Detail

Parameter

public Parameter(int index)
Method Detail

getSQL

public java.lang.String getSQL()
Description copied from class: Expression
Get the SQL statement of this expression. This may not always be the original SQL statement, specially after optimization.

Specified by:
getSQL in class Expression
Returns:
the SQL statement

setValue

public void setValue(Value v,
                     boolean closeOld)
Description copied from interface: ParameterInterface
Set the value of the parameter.

Specified by:
setValue in interface ParameterInterface
Parameters:
v - the new value
closeOld - if the old value (if one is set) should be closed

setValue

public void setValue(Value v)

getParamValue

public Value getParamValue()
Description copied from interface: ParameterInterface
Get the value of the parameter if set.

Specified by:
getParamValue in interface ParameterInterface
Returns:
the value or null

getValue

public Value getValue(Session 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

getType

public int getType()
Description copied from class: Expression
Return the data type. The data type may not be known before the optimization phase.

Specified by:
getType in interface ParameterInterface
Specified by:
getType in class Expression
Returns:
the type

mapColumns

public void mapColumns(ColumnResolver resolver,
                       int level)
Description copied from class: Expression
Map the columns of the resolver to expression columns.

Specified by:
mapColumns in class Expression
Parameters:
resolver - the column resolver
level - the subquery nesting level

checkSet

public void checkSet()
              throws java.sql.SQLException
Description copied from interface: ParameterInterface
Check if the value is set.

Specified by:
checkSet in interface ParameterInterface
Throws:
java.sql.SQLException - if not set.

optimize

public Expression optimize(Session 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

isConstant

public boolean isConstant()
Description copied from class: Expression
Check if this expression will always return the same value.

Overrides:
isConstant in class Expression
Returns:
if the expression is constant

isValueSet

public boolean isValueSet()
Description copied from class: Expression
Is the value of a parameter set.

Overrides:
isValueSet in class Expression
Returns:
if it is set

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                           boolean b)
Description copied from class: Expression
Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.

Specified by:
setEvaluatable in class Expression
Parameters:
tableFilter - the table filter
b - true if the table filter can return value

getScale

public int getScale()
Description copied from class: Expression
Get the scale of this expression.

Specified by:
getScale in interface ParameterInterface
Specified by:
getScale in class Expression
Returns:
the scale

getPrecision

public long getPrecision()
Description copied from class: Expression
Get the precision of this expression.

Specified by:
getPrecision in interface ParameterInterface
Specified by:
getPrecision in class Expression
Returns:
the precision

getDisplaySize

public int getDisplaySize()
Description copied from class: Expression
Get the display size of this expression.

Specified by:
getDisplaySize in class Expression
Returns:
the display size

updateAggregate

public void updateAggregate(Session session)
Description copied from class: Expression
Update an aggregate value. This method is called at statement execution time. It is usually called once for each row, but if the expression is used multiple times (for example in the column list, and as part of the HAVING expression) it is called multiple times - the row counter needs to be used to make sure the internal state is only updated once.

Specified by:
updateAggregate in class Expression
Parameters:
session - the session

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.

Specified by:
isEverything in class Expression
Parameters:
visitor - the visitor
Returns:
if the criteria can be fulfilled

getCost

public int getCost()
Description copied from class: Expression
Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.

Specified by:
getCost in class Expression
Returns:
the estimated cost

getNotIfPossible

public Expression getNotIfPossible(Session 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

setColumn

public void setColumn(Column column)

getIndex

public int getIndex()