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

Class RemoteSQLValue<H extends DataObject,R extends DataObject,T>

java.lang.Object

uk.ac.ed.epcc.webapp.jdbc.expr.RemoteSQLValue<H,R,T>

Type Parameters:

H - type of owning object

R - Type of remote object

T - target type of SQLValue

All Implemented Interfaces:

GroupingSQLValue<T>, SQLValue<T>, Targetted<T>

public abstract class RemoteSQLValue<H extends DataObject,R extends DataObject,T>
extends java.lang.Object
implements GroupingSQLValue<T>

Abstract superclass for a SQLValue that needs to follow a remote reference to access its data. This class performs the de-reference in java rather than using a join. However the embedded IndexedSQLValue may perform a join.

Field Summary

Fields

Modifier and Type	Field and Description
static Feature	CACHE_REMOTE_ACCESSOR_FEATURE

Constructor Summary

Constructors

Constructor and Description
RemoteSQLValue(AppContext c, IndexedSQLValue<H,R> a)

Method Summary

Modifier and Type	Method and Description
int	add(java.lang.StringBuilder sb, boolean qualify) Add the expression to a StringBuilder
AppContext	getContext()
protected Logger	getLogger()
java.util.List<PatternArgument>	getParameters(java.util.List<PatternArgument> list) Add parameters for this value to a list.
IndexedSQLValue<H,R>	getReferenceValue() SQLValue for remote object Reference
abstract T	getRemoteValue(R o) Get the remote value from the referenced object
abstract T	getRemoteValueFromNull() get the remote value corresponding to a null reference.
T	getRemoteValueFromReference(IndexedReference<R> ref)
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 class java.lang.Object

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

Methods inherited from interface uk.ac.ed.epcc.webapp.jdbc.expr.GroupingSQLValue

addGroup, checkContentsCanGroup, getGroupParameters, groupingIsomorphic

Methods inherited from interface uk.ac.ed.epcc.webapp.Targetted

getTarget

Field Detail

CACHE_REMOTE_ACCESSOR_FEATURE

public static final Feature CACHE_REMOTE_ACCESSOR_FEATURE

Constructor Detail

RemoteSQLValue

public RemoteSQLValue(AppContext c,
                      IndexedSQLValue<H,R> a)

Method Detail

getReferenceValue

public IndexedSQLValue<H,R> getReferenceValue()

SQLValue for remote object Reference

Returns:

DataObjectRefefenceAccessor

getRemoteValueFromReference

public T getRemoteValueFromReference(IndexedReference<R> ref)

getRemoteValue

public abstract T getRemoteValue(R o)

Get the remote value from the referenced object

Parameters:

o -

Returns:

remote value

getRemoteValueFromNull

public abstract T getRemoteValueFromNull()

get the remote value corresponding to a null reference.

Returns:

remote value

getContext

public AppContext getContext()

getLogger

protected Logger getLogger()

makeObject

public final T 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<T>

Parameters:

rs - ResultSet

Returns:

produced object

Throws:

DataException

java.sql.SQLException

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<T>

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<T>

Parameters:

list - to modify

Returns:

modified list of parameter objects

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<T>

Returns:

null or SQLFilter