uk.ac.ed.epcc.webapp.model.data

Class IndexedLinkManager<T extends IndexedLinkManager.Link<L,R>,L extends Indexed,R extends Indexed>

java.lang.Object

uk.ac.ed.epcc.webapp.model.data.DataObjectFactory<T>

uk.ac.ed.epcc.webapp.model.data.IndexedLinkManager<T,L,R>

Type Parameters:

T - Type of link object

L - type of left end

R - type of right end

All Implemented Interfaces:

Contexed, ContextCached, FormCreatorProducer, FormUpdateProducer<T>, FilterMatcher<T>, TypeConverter<T,java.lang.Number>, DataObjectSelector<T>, Selector<DataObjectItemInput<T>>, Owner<T>, IndexedProducer<T>, Tagged, Targetted<T>

Direct Known Subclasses:

LinkManager

public abstract class IndexedLinkManager<T extends IndexedLinkManager.Link<L,R>,L extends Indexed,R extends Indexed>
extends DataObjectFactory<T>

IndexedLinkManager is the base class of Factories that manage Link objects These classes manage many-to-one relationships between model level objects. The IndexedLinkManager class calls these the left and right objects. This call can be used to link any objects that implement Indexed. If both ends of the link are DataObject classes then the LinkManager sub-class should be used as this provides additional features. The actual Link DataObjects are pseudo inner classes of the IndexedLinkManager Often the Link objects will remain hidden inside the IndexedLinkManager sub-class and only be manipulated via an external interface. If we want to track the history of a Link object needs a status field that marks if the link is valid. This way the same object is used to record the link between two peer objects even if the link is broken and remade several times. Link can be selected based on the objects at the end on the link. e.g.

    // get a link
    Link l = manager.getLink(left_peer,right_peer);  // null if link does not exist
    
    // or
    Link l2 = manager.makeLink(left_peer,right_peer);  // make link if it does not already exist

IndexedLinkManager can navigate the links in either direction the subclass may choose only to expose one direction of navigation. Internally this is implemented using the LinkFilter and LinkFilterIterator classes which select a set a Link objects based on the value of one or other end.

   // links joining left_peer to something
   Iterator<Link> it = manager.getLinkIterator(left_peer,null,filter);

   // or go straight to the referenced object
   Iterator<Right>  right_it = manager.getRightIterator(left_peer,null,filter);

The Link class can cache references to the objects it points to, these cached values are retrieved using the getLeft() and getRight() methods.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IndexedLinkManager.Link<L extends Indexed,R extends Indexed> Link is an object representing an entry in a linkage table.
protected class	IndexedLinkManager.LinkFilter Filter for link objects This class handles filtering by the end points and can be extended by composition for example to select objects with a particular status.
protected static interface	IndexedLinkManager.LinkProvider<T extends IndexedLinkManager.Link<L,R>,L extends Indexed,R extends Indexed>
class	IndexedLinkManager.LinkUpdater
protected class	IndexedLinkManager.SQLLinkFilter Filter for link objects This class handles filtering by the end points and can be extended by composition for example to select objects with a particular status.

Nested classes/interfaces inherited from class uk.ac.ed.epcc.webapp.model.data.DataObjectFactory

DataObjectFactory.AbstractDataObjectInput, DataObjectFactory.AbstractFinder<X>, DataObjectFactory.DataObjectAcceptFilter, DataObjectFactory.DataObjectInput, DataObjectFactory.DataObjectIntegerInput, DataObjectFactory.DestAcceptFilter<T extends DataObject>, DataObjectFactory.FilterAdapter, DataObjectFactory.FilterCounter, DataObjectFactory.FilterExists, DataObjectFactory.FilterIterator, DataObjectFactory.FilterSelector, DataObjectFactory.FilterSet, DataObjectFactory.Finder, DataObjectFactory.MakeRemoteFilterVisitor<R extends DataObject>, DataObjectFactory.MatchFilter, DataObjectFactory.ReferencedAdapter<I extends Indexed>, DataObjectFactory.ReferenceIterator<I extends Indexed>, DataObjectFactory.SortingDataObjectInput, DataObjectFactory.TimeAcceptFilter<T extends DataObject>, DataObjectFactory.TimeFilter

Field Summary

Fields inherited from class uk.ac.ed.epcc.webapp.model.data.DataObjectFactory

AUTO_CREATE_TABLES_FEATURE, COMPOSITES_SUFFIX, REJECT_MULTIPLE_RESULT_FEATURE, res

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	IndexedLinkManager()
protected	IndexedLinkManager(AppContext c, java.lang.String table, IndexedProducer<L> left_fac, java.lang.String left_field, IndexedProducer<R> right_fac, java.lang.String right_field)

Method Summary

Modifier and Type	Method and Description
java.util.Set<L>	addLeftSet(java.util.Set<L> res, R r, BaseFilter<T> f) Add to a set of Left Objects
java.util.Set<R>	addRightSet(java.util.Set<R> res, L l, BaseFilter<T> f) Add to a set of Right objects
TableSpecification	getDefaultTableSpecification(AppContext c, java.lang.String table) Get the default table specification if the table is to be created.
protected TableSpecification	getDefaultTableSpecification(AppContext c, java.lang.String table, IndexedProducer<L> leftFac, java.lang.String leftField, IndexedProducer<R> rightFac, java.lang.String rightField)
FilterResult<T>	getFilterResult(L l, R r, BaseFilter<T> fil) create a FilterResult of Link objects
TableSpecification	getFinalTableSpecification(AppContext c, java.lang.String table, IndexedProducer<L> leftFac, java.lang.String leftField, IndexedProducer<R> rightFac, java.lang.String rightField)
FormUpdate<T>	getFormUpdate(AppContext c) produce a FormUpdate for the target type appropriate for the requesting user
HistoryHandler<T>	getHistoryHandler()
java.lang.String	getLeftField()
SQLFilter<T>	getLeftFilter(L l)
IndexedProducer<L>	getLeftProducer()
java.util.Set<L>	getLeftSet(R r, BaseFilter<T> f) Get a Set of Left objects
T	getLink(L left_end, R right_end) get the Link object connecting the specified end objects
java.lang.String	getRightField()
SQLFilter<T>	getRightFilter(R r)
IndexedProducer<R>	getRightProducer()
java.util.Set<R>	getRightSet(L l, BaseFilter<T> f) Get a Set of Right objects
TableSpecification	getTableSpecification() Get the default TableSpecification from a fully constructed factory.
java.lang.Class<T>	getTarget() Get a bound on the type of object produced by this factory for run-time checking.
protected boolean	isLeft(java.lang.Object o)
protected boolean	isRight(java.lang.Object o)
protected HistoryHandler<T>	makeHistoryHandler() create a new HistoryFactory suitable for the Link objects produced by this class.
protected T	makeLink(L left_end, R right_end) Return a link creating one and calling setup if it does not exist.
void	modifyHistoryTable(TableSpecification spec) Add Tracking fields to the history table default specification
protected T	selectLink(L left_end, R right_end) method to call when from selector code normally the same as getLink but may need to be overridden to automatically create objects (beware of unwanted side effects in this case).
protected void	setContext(AppContext c, java.lang.String table, IndexedProducer<L> left_fac, java.lang.String left_field, IndexedProducer<R> right_fac, java.lang.String right_field)
void	setHistoryHandler(HistoryHandler<T> handler) Set the HistoryHandler explicitly.
protected void	updateHistory(T val)
protected boolean	useAutoHistory() Do we automatically update the history as part of commit.

Methods inherited from class uk.ac.ed.epcc.webapp.model.data.DataObjectFactory

all, allowPreSelect, canCreate, canUpdate, checkComposite, convertToDestinationFilter, customiseForm, equals, exists, find, find, find, find, find, getAllIterator, getComposite, getComposites, getComposites, getConfigTag, getContext, getCount, getDefaultRelationshipFilter, getDefaults, getDestFilter, getExcludeFilter, getFieldConstraints, getFieldHelp, getFilter, getFilter, getFilter, getFinalSelectFilter, getFinalTableSpecification, getFindFilter, getFormCreator, getID, getIndex, getInput, getInput, getInput, getLogger, getMaxIdentifierLength, getNullable, getOptional, getOrder, getProperty, getReferenced, getReferenceFieldType, getReferenceFieldType, getRemoteFilter, getRemoteSQLFilter, getResult, getResult, getSelectFilter, getSelector, getSelector, getSelectors, getSupress, getTableStructureContributers, getTag, getTranslations, getUniqueIdName, hasComposite, hashCode, isMine, isMine, isMyReference, isValid, makeBDO, makeBDO, makeObject, makeRecord, makeReference, makeReference, matches, narrowSelector, narrowSelector, observeComposite, OrderBy, postCreateTableSetup, postSetContext, release, restrictDefaultInput, setComposites, setContext, setContext, setContextWithMake, setProperty, toString, updateTable

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

IndexedLinkManager

protected IndexedLinkManager(AppContext c,
                             java.lang.String table,
                             IndexedProducer<L> left_fac,
                             java.lang.String left_field,
                             IndexedProducer<R> right_fac,
                             java.lang.String right_field)

IndexedLinkManager

protected IndexedLinkManager()

Method Detail

setContext

protected void setContext(AppContext c,
                          java.lang.String table,
                          IndexedProducer<L> left_fac,
                          java.lang.String left_field,
                          IndexedProducer<R> right_fac,
                          java.lang.String right_field)

getDefaultTableSpecification

public final TableSpecification getDefaultTableSpecification(AppContext c,
                                                             java.lang.String table)

Description copied from class: DataObjectFactory

Get the default table specification if the table is to be created. A null result means that a default specification is not available and the table will not be created.

Overrides:

getDefaultTableSpecification in class DataObjectFactory<T extends IndexedLinkManager.Link<L,R>>

Parameters:

c - AppContext

table - String table name.

Returns:

null or TableSpecification

getDefaultTableSpecification

protected TableSpecification getDefaultTableSpecification(AppContext c,
                                                          java.lang.String table,
                                                          IndexedProducer<L> leftFac,
                                                          java.lang.String leftField,
                                                          IndexedProducer<R> rightFac,
                                                          java.lang.String rightField)

getFinalTableSpecification

public final TableSpecification getFinalTableSpecification(AppContext c,
                                                           java.lang.String table,
                                                           IndexedProducer<L> leftFac,
                                                           java.lang.String leftField,
                                                           IndexedProducer<R> rightFac,
                                                           java.lang.String rightField)

getTableSpecification

public final TableSpecification getTableSpecification()

Description copied from class: DataObjectFactory

Get the default TableSpecification from a fully constructed factory. This can only be called after auto-table generation.

Overrides:

getTableSpecification in class DataObjectFactory<T extends IndexedLinkManager.Link<L,R>>

Returns:

getHistoryHandler

public final HistoryHandler<T> getHistoryHandler()

setHistoryHandler

public final void setHistoryHandler(HistoryHandler<T> handler)

Set the HistoryHandler explicitly. Normally this is created using makeHistoryHandler() but this allows us to set the reference when a handler is created directly.

Parameters:

handler -

getLeftProducer

public IndexedProducer<L> getLeftProducer()

getLeftField

public java.lang.String getLeftField()

getLeftFilter

public SQLFilter<T> getLeftFilter(L l)

getLeftSet

public java.util.Set<L> getLeftSet(R r,
                                   BaseFilter<T> f)
                            throws DataException

Get a Set of Left objects

Parameters:

r - Right Indexed required null for any

f - extension Filter

Returns:

Set of Left objects

Throws:

DataException

addLeftSet

public java.util.Set<L> addLeftSet(java.util.Set<L> res,
                                   R r,
                                   BaseFilter<T> f)
                            throws DataException

Add to a set of Left Objects

Parameters:

res - Set to add too

r - Right Indexed required null for any

f - extension Filter

Returns:

Set of Left objects

Throws:

DataException

getLink

public final T getLink(L left_end,
                       R right_end)
                throws DataException

get the Link object connecting the specified end objects

Parameters:

left_end - Left Indexed

right_end - Right Indexed

Returns:

Link or null if link does not exist.

Throws:

DataException

getFilterResult

public FilterResult<T> getFilterResult(L l,
                                       R r,
                                       BaseFilter<T> fil)
                                throws DataFault

create a FilterResult of Link objects

Parameters:

l - Left Indexed required null for any

r - Right Indexed required null for any

fil - extension Filter

Returns:

Iterator over Link

Throws:

DataFault

DataFault

getRightProducer

public IndexedProducer<R> getRightProducer()

getRightField

public java.lang.String getRightField()

getRightFilter

public SQLFilter<T> getRightFilter(R r)

getRightSet

public java.util.Set<R> getRightSet(L l,
                                    BaseFilter<T> f)
                             throws DataException

Get a Set of Right objects

Parameters:

l - Left DataObject required null for any

f - extension Filter

Returns:

Set of Right objects

Throws:

DataException

addRightSet

public java.util.Set<R> addRightSet(java.util.Set<R> res,
                                    L l,
                                    BaseFilter<T> f)
                             throws DataException

Add to a set of Right objects

Parameters:

res - Set to add too

l - Left DataObject required null for any

f - extension Filter

Returns:

Set of Right objects

Throws:

DataException

isLeft

protected boolean isLeft(java.lang.Object o)

isRight

protected boolean isRight(java.lang.Object o)

makeHistoryHandler

protected HistoryHandler<T> makeHistoryHandler()

create a new HistoryFactory suitable for the Link objects produced by this class. This method should be re-implemented by any subclass that wishes to implement History tracking. Note that HistoryFactories contain a reference to their Peer Factory so it will be cleaner to pass this object into the constructor of the HistoryFactory

Returns:

LinkHistoryManager

modifyHistoryTable

public void modifyHistoryTable(TableSpecification spec)

Add Tracking fields to the history table default specification

Parameters:

spec -

makeLink

protected final T makeLink(L left_end,
                           R right_end)
                    throws java.lang.Exception

Return a link creating one and calling setup if it does not exist. These methods are protected in case the superclass needs to add additional checks or setup as well.

Parameters:

left_end - Left Indexed

right_end - Right Indexed

Returns:

Link

Throws:

DataException

java.lang.Exception

selectLink

protected T selectLink(L left_end,
                       R right_end)
                throws java.lang.Exception

method to call when from selector code normally the same as getLink but may need to be overridden to automatically create objects (beware of unwanted side effects in this case). Ususally want to Override #canCreate(uk.ac.ed.epcc.webapp.SessionService) in that case.

Parameters:

left_end -

right_end -

Returns:

Link

Throws:

DataException

java.lang.Exception

getFormUpdate

public FormUpdate<T> getFormUpdate(AppContext c)

Description copied from interface: FormUpdateProducer

produce a FormUpdate for the target type appropriate for the requesting user

Specified by:

getFormUpdate in interface FormUpdateProducer<T extends IndexedLinkManager.Link<L,R>>

Overrides:

getFormUpdate in class DataObjectFactory<T extends IndexedLinkManager.Link<L,R>>

Parameters:

c - AppContext

Returns:

FormUpdate or null

useAutoHistory

protected boolean useAutoHistory()

Do we automatically update the history as part of commit.

Returns:

boolean

updateHistory

protected void updateHistory(T val)

getTarget

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

Description copied from class: DataObjectFactory

Get a bound on the type of object produced by this factory for run-time checking. This implements IndexedProducer.getTarget(). Normally this method should be overridden each time we make a sub-class that narrows the produced type. However checks should still pass if the super-type method is retained.

Specified by:

getTarget in interface IndexedProducer<T extends IndexedLinkManager.Link<L,R>>

Specified by:

getTarget in interface Targetted<T extends IndexedLinkManager.Link<L,R>>

Overrides:

getTarget in class DataObjectFactory<T extends IndexedLinkManager.Link<L,R>>

Returns:

Class object for return type