com.goldencode.p2j.persist

Class ForeignResolver

java.lang.Object

com.goldencode.p2j.persist.ForeignResolver

final class ForeignResolver
extends java.lang.Object

Resolves records on either end of a foreign key association, based upon the values of one or more properties in a DMO, where those properties represent the legacy "foreign key" in the pre-conversion application. This allows a record's foreign key to be kept in synch with changes to these legacy key properties. This is necessary because a true foreign key is only added to a table as part of the conversion process; the legacy application knows nothing of these new keys, so the runtime must keep them in synch as the legacy key values change.

Field Summary

Fields

Modifier and Type	Field and Description
private Database	database The associated database
private java.util.ArrayList<FieldReference>	fieldRefs Field references used to retrieve query substitution values
private java.lang.String	fql FQL query statement
private RelationInfo	info Information about the primary/foreign key relation
private boolean	inverse Does resolver walk the foreign key association from the foreign end?
private static CentralLogger	LOG Logger

Constructor Summary

Constructors

Constructor and Description
ForeignResolver(RelationInfo info, RecordBuffer buffer, boolean inverse) Constructor.

Method Summary

Modifier and Type	Method and Description
private void	createFieldRefs(java.lang.Class<? extends DataModelObject> dmoIface, java.util.Iterator<java.lang.String> propIter) Construct one FieldReference object for each legacy key property which will be used as a query substitution parameter during record resolution.
private java.lang.String	generateFQL(RelationInfo info) Generate the FQL statement which will be used for record resolution, using the information stored in the relation descriptor.
private java.lang.Object[]	getArguments(Record dmo) Get the current values of all legacy key properties for this relation, from the given record.
(package private) RelationInfo	getInfo() Get the descriptor object which contains information about the relation associated with this resolver.
(package private) java.lang.Long	resolveForeign(RecordBuffer buffer) Resolve a foreign record using the values of one or more legacy key properties in buffer's current record.
(package private) java.util.List<java.lang.Long>	resolveLocal(RecordBuffer buffer) Resolve zero or more records which refer via foreign key association to the record currently stored in buffer, using the values of one or more legacy key properties in that record.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final CentralLogger LOG

Logger

info

private final RelationInfo info

Information about the primary/foreign key relation

fql

private final java.lang.String fql

FQL query statement

fieldRefs

private final java.util.ArrayList<FieldReference> fieldRefs

Field references used to retrieve query substitution values

inverse

private final boolean inverse

Does resolver walk the foreign key association from the foreign end?

database

private final Database database

The associated database

Constructor Detail

ForeignResolver

ForeignResolver(RelationInfo info,
                RecordBuffer buffer,
                boolean inverse)

Constructor.

Parameters:

info - Descriptor of the relation between the local and foreign DMOs.

buffer - A record buffer which represents the "local" (i.e., referring) DMO if inverse is false, or which represents the foreign (i.e., referent) DMO if inverse is true.

inverse - true to construct an object which resolves the "local" (i.e., referring) DMO(s) given a foreign (i.e., referent) DMO; false to construct an object which resolves the foreign DMO given a local DMO.

Method Detail

resolveForeign

java.lang.Long resolveForeign(RecordBuffer buffer)
                       throws PersistenceException

Resolve a foreign record using the values of one or more legacy key properties in buffer's current record.

Parameters:

buffer - The record buffer containing the current, local record for which a related, foreign record must be found.

Returns:

The primary key ID of the foreign record associated with the current value(s) of the legacy key(s) in buffer's current record, or null if none was found.

Throws:

PersistenceException - if any error occurs querying the foreign record from the database.

java.lang.IllegalStateException - if the current record in the buffer is null, or if this object has been configured to retrieve the record for the inverse, foreign key association.

resolveLocal

java.util.List<java.lang.Long> resolveLocal(RecordBuffer buffer)
                                     throws PersistenceException

Resolve zero or more records which refer via foreign key association to the record currently stored in buffer, using the values of one or more legacy key properties in that record.

Parameters:

buffer - The record buffer containing the current, foreign record for which one or more related, "local" records must be found.

Returns:

A list of zero or more primary key IDs for the record(s), if any, associated with the current value(s) of the legacy key(s) in buffer's current record.

Throws:

PersistenceException - if any error occurs querying the database.

java.lang.IllegalStateException - if the current record in the buffer is null, or if this object has not been configured to retrieve the record for the inverse, foreign key association..

getInfo

RelationInfo getInfo()

Get the descriptor object which contains information about the relation associated with this resolver.

Returns:

Relation descriptor.

getArguments

private java.lang.Object[] getArguments(Record dmo)

Get the current values of all legacy key properties for this relation, from the given record. These will become query substitution values when searching for the foreign record.

Parameters:

dmo - Record currently stored in the record buffer.

Returns:

Array of current, legacy key property values.

generateFQL

private java.lang.String generateFQL(RelationInfo info)

Generate the FQL statement which will be used for record resolution, using the information stored in the relation descriptor.

Parameters:

info - Relation descriptor.

Returns:

FQL query statement.

createFieldRefs

private void createFieldRefs(java.lang.Class<? extends DataModelObject> dmoIface,
                             java.util.Iterator<java.lang.String> propIter)

Construct one FieldReference object for each legacy key property which will be used as a query substitution parameter during record resolution. Store these objects in a list for later access.

Parameters:

dmoIface - Business interface which the field references will invoke to retrieve property values.

propIter - Iterator on the names of those DMO properties which form the legacy foreign key.