com.caucho.db.sql
Class MaxExpr

java.lang.Object
  com.caucho.db.sql.Expr
      com.caucho.db.sql.FunExpr
          com.caucho.db.sql.MaxExpr

All Implemented Interfaces:

GroupExpr

public class MaxExpr
extends FunExpr
implements GroupExpr

Field Summary

Fields inherited from class com.caucho.db.sql.Expr

FALSE, TRUE, UNKNOWN

Constructor Summary

MaxExpr()

Method Summary

protected void	addArg(Expr expr)
Expr	bind(Query query)
double	evalDouble(QueryContext context) Evaluates the expression as a double.
void	evalGroup(QueryContext context) Evaluates aggregate functions during the group phase.
long	evalLong(QueryContext context) Evaluates the expression as a long.
java.lang.String	evalString(QueryContext context) Evaluates the expression as a string.
java.lang.Class	getType() Returns the expected result type of the expression.
boolean	isNull(QueryContext context) Returns true if the value is null.
java.lang.String	toString()

Methods inherited from class com.caucho.db.sql.Expr

cost, createOrder, evalBoolean, evalBytes, evalDate, evalEqual, evalEqual, evalStream, evalToBuffer, evalToBuffer, evalToResult, getIndexExpr, getName, getSQLType, getTable, getTypeCode, indexCost, indexSubCost, initGroup, isBinaryStream, isBoolean, isDouble, isLong, isNullable, isParam, isSelect, splitAnd, subCost, updateDouble, updateLong, updateString

Methods inherited from class java.lang.Object

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

Constructor Detail

MaxExpr

public MaxExpr()

Method Detail

addArg

protected void addArg(Expr expr)
               throws java.sql.SQLException

Specified by:

addArg in class FunExpr

Throws:

java.sql.SQLException

bind

public Expr bind(Query query)
          throws java.sql.SQLException

Overrides:

bind in class Expr

Throws:

java.sql.SQLException

getType

public java.lang.Class getType()

Returns the expected result type of the expression.

Overrides:

getType in class Expr

evalGroup

public void evalGroup(QueryContext context)
               throws java.sql.SQLException

Evaluates aggregate functions during the group phase.

Overrides:

evalGroup in class Expr

Parameters:

context - the current database tuple

Throws:

java.sql.SQLException

isNull

public boolean isNull(QueryContext context)
               throws java.sql.SQLException

Returns true if the value is null.

Overrides:

isNull in class Expr

Parameters:

queryContext - the query context

Returns:

true if null

Throws:

java.sql.SQLException

evalDouble

public double evalDouble(QueryContext context)
                  throws java.sql.SQLException

Evaluates the expression as a double.

Overrides:

evalDouble in class Expr

Parameters:

rows - the current tuple being evaluated

Returns:

the double value

Throws:

java.sql.SQLException

evalLong

public long evalLong(QueryContext context)
              throws java.sql.SQLException

Evaluates the expression as a long.

Overrides:

evalLong in class Expr

Parameters:

rows - the current tuple being evaluated

Returns:

the long value

Throws:

java.sql.SQLException

evalString

public java.lang.String evalString(QueryContext context)
                            throws java.sql.SQLException

Evaluates the expression as a string.

Overrides:

evalString in class Expr

Parameters:

rows - the current tuple being evaluated

Returns:

the string value

Throws:

java.sql.SQLException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object