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

Class LinkManager<T extends LinkManager.Link<L,R>,L extends DataObject,R extends DataObject>

java.lang.Object

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

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

uk.ac.ed.epcc.webapp.model.data.LinkManager<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:

RelationshipLinkManager, ResponseDataManager

public abstract class LinkManager<T extends LinkManager.Link<L,R>,L extends DataObject,R extends DataObject>
extends IndexedLinkManager<T,L,R>

LinkManager is the base class of Factories that manage Link objects These classes manage many-to-one relationships between model level objects. The LinkManager class calls these the left and right objects. The actual Link DataObjects are pseudo inner classes of the LinkManager Often the Link objects will remain hidden inside the LinkManager 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

LinkManager 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 or SQLLinkFilter 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.

LinkManager provides a single point in the code to optionally apply SQL join optimisations. A SQL join can be used to initialise the cache fields in the Link object when it is created.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	LinkManager.JoinLinkFilterIterator Version of FilterIterator that optimises the end object caches by performing a join on target tables.
class	LinkManager.JoinLinkMapper A ResultMapper that handles setting the links from joins.
class	LinkManager.LeftAcceptFilter A wrapper to convert a non SQL filter on the link object into an AcceptFilter on the left object
static class	LinkManager.Link<L extends DataObject,R extends DataObject> Link is an object representing an entry in a linkage table.
class	LinkManager.LinkInput An input for Link objects implemented as a CompositeInput
class	LinkManager.LinkResult A FilterResult for link objects.
class	LinkManager.RightAcceptFilter A wrapper to convert a non SQL filter on the link object into an AcceptFilter on the right object

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

IndexedLinkManager.LinkFilter, IndexedLinkManager.LinkProvider<T extends IndexedLinkManager.Link<L,R>,L extends Indexed,R extends Indexed>, IndexedLinkManager.LinkUpdater, IndexedLinkManager.SQLLinkFilter

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

Modifier and Type	Field and Description
static Feature	USE_JOIN

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

Method Summary

Modifier and Type	Method and Description
T	find(L l, R r, BaseFilter<T> f)
T	find(L l, R r, BaseFilter<T> f, boolean allow_null)
protected TableSpecification	getDefaultTableSpecification(AppContext c, java.lang.String table, IndexedProducer<L> leftFac, java.lang.String leftField, IndexedProducer<R> rightFac, java.lang.String rightField)
BaseFilter<T>	getFilter(L left, R right, BaseFilter<T> fil)
FilterResult<T>	getFilterResult(L left, R right, BaseFilter<T> fil) get A FilterResult for link objects
DataObjectItemInput<T>	getInput() get the default Input for this Factory Default behaviour is to use the DataObjectFactory.getSelectFilter() method to generate a DataObjectFactory.DataObjectInput but not to restrict the parse values (default value of DataObjectFactory.restrictDefaultInput() so existing values that don't match the select filter are still valid.
DataObjectFactory<L>	getLeftFactory()
BaseFilter<L>	getLeftFilter(BaseFilter<T> fil) Get a filter for the left peer from a filter on the link
SQLFilter<L>	getLeftFilter(SQLFilter<T> fil) Get a filter for the left peer from a filter on the link
protected DataObjectItemInput<L>	getLeftInput()
SQLFilter<T>	getLeftJoinFilter(SQLFilter<L> fil) Get a SQLFilter for the link from a SQLFilter on the left peer
BaseFilter<T>	getLeftRemoteFilter(BaseFilter<L> fil) get a BaseFilter for the link from a BaseFilter on the left peer
long	getLinkCount(L l, R r, BaseFilter<T> f)
CloseableIterator<T>	getLinkIterator(L l, R r, BaseFilter<T> f, boolean use_join)
DataObjectFactory<R>	getRightFactory()
BaseFilter<R>	getRightFilter(BaseFilter<T> fil) Get a filter for the right peer from a filter on the link.
SQLFilter<R>	getRightFilter(SQLFilter<T> fil) Get a SQLFilter for the right peer from a SQLFilter on the link.
protected DataObjectItemInput<R>	getRightInput()
SQLFilter<T>	getRightJoinFilter(SQLFilter<R> fil) Get a SQLFilter for the link from a SQLFilter on the right peer
BaseFilter<T>	getRightRemoteFilter(BaseFilter<R> fil) get a BaseFilter for the link from a BaseFilter on the right peer.
protected java.util.Map<java.lang.String,Selector>	getSelectors() Get a Map of selectors to use for forms of this type.
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)

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

addLeftSet, addRightSet, getDefaultTableSpecification, getFinalTableSpecification, getFormUpdate, getHistoryHandler, getLeftField, getLeftFilter, getLeftProducer, getLeftSet, getLink, getRightField, getRightFilter, getRightProducer, getRightSet, getTableSpecification, makeHistoryHandler, makeLink, modifyHistoryTable, selectLink, setContext, setHistoryHandler, updateHistory, useAutoHistory

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, getLogger, getMaxIdentifierLength, getNullable, getOptional, getOrder, getProperty, getReferenced, getReferenceFieldType, getReferenceFieldType, getRemoteFilter, getRemoteSQLFilter, getResult, getResult, getSelectFilter, getSelector, getSelector, 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

Field Detail

USE_JOIN

public static final Feature USE_JOIN

Constructor Detail

LinkManager

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

LinkManager

protected LinkManager()

Method Detail

getDefaultTableSpecification

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

Overrides:

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

getInput

public DataObjectItemInput<T> getInput()

Description copied from class: DataObjectFactory

get the default Input for this Factory Default behaviour is to use the DataObjectFactory.getSelectFilter() method to generate a DataObjectFactory.DataObjectInput but not to restrict the parse values (default value of DataObjectFactory.restrictDefaultInput() so existing values that don't match the select filter are still valid.

Specified by:

getInput in interface Selector<DataObjectItemInput<T extends LinkManager.Link<L,R>>>

Overrides:

getInput in class DataObjectFactory<T extends LinkManager.Link<L,R>>

Returns:

Input

getLeftFactory

public DataObjectFactory<L> getLeftFactory()

getLinkIterator

public CloseableIterator<T> getLinkIterator(L l,
                                            R r,
                                            BaseFilter<T> f,
                                            boolean use_join)
                                     throws DataFault

Throws:

DataFault

getLinkCount

public long getLinkCount(L l,
                         R r,
                         BaseFilter<T> f)
                  throws DataException

Throws:

DataException

find

public T find(L l,
              R r,
              BaseFilter<T> f)
       throws DataException

Throws:

DataException

find

public T find(L l,
              R r,
              BaseFilter<T> f,
              boolean allow_null)
       throws DataException

Throws:

DataException

getRightFactory

public DataObjectFactory<R> getRightFactory()

getFilterResult

public FilterResult<T> getFilterResult(L left,
                                       R right,
                                       BaseFilter<T> fil)
                                throws DataFault

get A FilterResult for link objects

Overrides:

getFilterResult in class IndexedLinkManager<T extends LinkManager.Link<L,R>,L extends DataObject,R extends DataObject>

Parameters:

left - Left DataObject required null for any

right - Right DataObject requeired null for any

fil - Additional BaseFilter

Returns:

FilterResult

Throws:

DataFault

getFilter

public BaseFilter<T> getFilter(L left,
                               R right,
                               BaseFilter<T> fil)

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 LinkManager.Link<L,R>>

Specified by:

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

Overrides:

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

Returns:

Class object for return type

getLeftFilter

public BaseFilter<L> getLeftFilter(BaseFilter<T> fil)

Get a filter for the left peer from a filter on the link

Parameters:

fil - SQLFilter on self

Returns:

SQLFilter on left peer

getLeftFilter

public SQLFilter<L> getLeftFilter(SQLFilter<T> fil)

Get a filter for the left peer from a filter on the link

Parameters:

fil - SQLFilter on self

Returns:

SQLFilter on left peer

getLeftJoinFilter

public SQLFilter<T> getLeftJoinFilter(SQLFilter<L> fil)

Get a SQLFilter for the link from a SQLFilter on the left peer

Parameters:

fil - SQLFilter on left peer

Returns:

SQLFilter on self

getLeftRemoteFilter

public BaseFilter<T> getLeftRemoteFilter(BaseFilter<L> fil)

get a BaseFilter for the link from a BaseFilter on the left peer

Parameters:

fil - BaseFilter on left peer

Returns:

BaseFilter on self

getRightFilter

public BaseFilter<R> getRightFilter(BaseFilter<T> fil)

Get a filter for the right peer from a filter on the link.

Parameters:

fil - SQLFilter on self

Returns:

SQLFilter on left peer

getRightFilter

public SQLFilter<R> getRightFilter(SQLFilter<T> fil)

Get a SQLFilter for the right peer from a SQLFilter on the link.

Parameters:

fil - SQLFilter on self

Returns:

SQLFilter on left peer

getRightJoinFilter

public SQLFilter<T> getRightJoinFilter(SQLFilter<R> fil)

Get a SQLFilter for the link from a SQLFilter on the right peer

Parameters:

fil - SQLFilter on right peer

Returns:

SQLFilter on self

getRightRemoteFilter

public BaseFilter<T> getRightRemoteFilter(BaseFilter<R> fil)

get a BaseFilter for the link from a BaseFilter on the right peer.

Parameters:

fil - BaseFilter in right peer

Returns:

BaseFilter on self

isLeft

protected boolean isLeft(java.lang.Object o)

Overrides:

isLeft in class IndexedLinkManager<T extends LinkManager.Link<L,R>,L extends DataObject,R extends DataObject>

isRight

protected boolean isRight(java.lang.Object o)

Overrides:

isRight in class IndexedLinkManager<T extends LinkManager.Link<L,R>,L extends DataObject,R extends DataObject>

getLeftInput

protected DataObjectItemInput<L> getLeftInput()

Returns:

getRightInput

protected DataObjectItemInput<R> getRightInput()

Returns:

getSelectors

protected java.util.Map<java.lang.String,Selector> getSelectors()

Description copied from class: DataObjectFactory

Get a Map of selectors to use for forms of this type. This method provides a class specific set of defaults but the specific form classes can override this.

Overrides:

getSelectors in class DataObjectFactory<T extends LinkManager.Link<L,R>>

Returns:

Map

See Also:

DataObjectFormFactory