uk.ac.ed.epcc.webapp.jdbc.expr

Class AverageValueSQLValue

java.lang.Object

uk.ac.ed.epcc.webapp.jdbc.expr.AverageValueSQLValue

All Implemented Interfaces:

SQLValue<AverageValue>, Targetted<AverageValue>

public class AverageValueSQLValue
extends java.lang.Object
implements SQLValue<AverageValue>

A SQLValue that generates an AverageValue from a combination of a sum SQLValue and a count field.

Constructor Summary

Constructors

Constructor and Description
AverageValueSQLValue(SQLExpression<? extends java.lang.Number> value)

Method Summary

Modifier and Type	Method and Description
int	add(java.lang.StringBuilder sb, boolean qualify) Add the expression to a StringBuilder
java.util.List<PatternArgument>	getParameters(java.util.List<PatternArgument> list) Add parameters for this value to a list.
SQLFilter	getRequiredFilter() Get an SQLFilter required to be added to the filter set.
java.lang.Class<AverageValue>	getTarget() Get the type of the returned object as far as it is known.
AverageValue	makeObject(java.sql.ResultSet rs, int pos) Extract a result of the expression from a ResultSet into an object of the specified type.

Methods inherited from class java.lang.Object

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

Constructor Detail

AverageValueSQLValue

public AverageValueSQLValue(SQLExpression<? extends java.lang.Number> value)

Method Detail

getTarget

public java.lang.Class<AverageValue> getTarget()

Description copied from interface: Targetted

Get the type of the returned object as far as it is known. Normally this should be the erasure type corresponding to T.

Specified by:

getTarget in interface Targetted<AverageValue>

Returns:

Class object for return type

add

public int add(java.lang.StringBuilder sb,
               boolean qualify)

Description copied from interface: SQLValue

Add the expression to a StringBuilder

Specified by:

add in interface SQLValue<AverageValue>

Parameters:

sb - StringBuilder to modify

qualify - boolean should fields be qualified with the table name

Returns:

number of fields added

getParameters

public java.util.List<PatternArgument> getParameters(java.util.List<PatternArgument> list)

Description copied from interface: SQLValue

Add parameters for this value to a list.

Specified by:

getParameters in interface SQLValue<AverageValue>

Parameters:

list - to modify

Returns:

modified list of parameter objects

makeObject

public AverageValue makeObject(java.sql.ResultSet rs,
                               int pos)
                        throws DataException,
                               java.sql.SQLException

Description copied from interface: SQLValue

Extract a result of the expression from a ResultSet into an object of the specified type. Note that this method is also used to extract the result of functions over the result type.

Specified by:

makeObject in interface SQLValue<AverageValue>

Parameters:

rs - ResultSet

Returns:

produced object

Throws:

DataException

java.sql.SQLException

getRequiredFilter

public SQLFilter getRequiredFilter()

Description copied from interface: SQLValue

Get an SQLFilter required to be added to the filter set. This is usually to implement a join.

Specified by:

getRequiredFilter in interface SQLValue<AverageValue>

Returns:

null or SQLFilter