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

Interface SQLValue<T>

Type Parameters:

T - type produced

All Superinterfaces:

Targetted<T>

All Known Subinterfaces:

DateSQLExpression, FieldSQLExpression<T,X>, FieldValue<T,X>, GroupingSQLValue<T>, IndexedSQLValue<T,I>, NestedSQLValue<T,N>, SQLAccessor<T,R>, SQLExpression<T>, WrappedSQLExpression<T>

All Known Implementing Classes:

AbstractSelfSQLValue, AliasSQLValue, ArrayFuncExpression, ArrayFuncValue, AverageValueSQLValue, BinaryExpression, BinarySQLValue, BooleanFieldExpression, CaseExpression, CastDoubleSQLExpression, CastLongSQLExpression, CompareSQLExpression, CompareSQLValue, CompositeIndexedSQLValue, ConcatSQLExpression, ConstExpression, ConstIndexedSQLValue, CountDistinctExpression, DateDerefSQLExpression, DateFieldExpression, DateSQLValue, DerefSQLExpression, DistinctCountSQLValue, DoubleConvertSQLValue, DurationConvertSQLValue, DurationFieldValue, DurationSecondConvertSQLValue, DurationSQLExpression, DurationSQLValue, FieldExpression, FuncExpression, IndexedFieldValue, IntConvertSQLValue, LabellerSQLValue, LengthExpression, LocateSQLExpression, LocateSQLValue, LongConvertSQLValue, MillisecondSQLValue, MysqlDateConverter, MysqlMillisecondConverter, MysqlSQLHashExpression, MysqlTimestampDiffExpr, NumberFieldExpression, PostgresqlDateConverter, PostgresqlMillisecondConverter, RemoteSQLValue, RoundSQLExpression, SelfIdExpression, SelfSQLValue, SQLSelectValue, SQLValuePatternTransform, StreamDataFieldExpression, StringConvertSQLExpression, StringConvertSQLValue, StringFieldExpression, TimestampDateFieldExpression, TupleSelfSQLValue, TypeConverterSQLValue, TypeFilterProducerSQLValue, TypeProducerFieldValue

public interface SQLValue<T>
extends Targetted<T>

An object that can create a value from a SQL fragment. We encode both the SQL fragment used in the select and the java code needed to convert this to and from a java type in the same class as there is an implicit dependency between the two. Note that though there must be a one-to-one relation between the result of the select and the returned object the makeObject method may apply an arbitrary mapping.

See Also:

SQLExpression, GroupingSQLValue, NestedSQLValue

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.
default SQLFilter	getRequiredFilter() Get an SQLFilter required to be added to the filter set.
T	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 interface uk.ac.ed.epcc.webapp.Targetted

getTarget

Method Detail

add

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

Add the expression to a StringBuilder

Parameters:

sb - StringBuilder to modify

qualify - boolean should fields be qualified with the table name

Returns:

number of fields added

getParameters

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

Add parameters for this value to a list.

Parameters:

list - to modify

Returns:

modified list of parameter objects

makeObject

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

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.

Parameters:

rs - ResultSet

pos -

Returns:

produced object

Throws:

DataException

java.sql.SQLException

getRequiredFilter

default SQLFilter getRequiredFilter()

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

Returns:

null or SQLFilter