com.goldencode.p2j.persist

Class DynamicLegacyKeyJoin

java.lang.Object

com.goldencode.p2j.persist.AbstractJoin

com.goldencode.p2j.persist.DynamicLegacyKeyJoin

final class DynamicLegacyKeyJoin
extends AbstractJoin

An implementation of a natural join helper used by dynamic query types. The FQL query string snippet created by this class joins the local DMO with the inverse DMO using a query substitution parameters (?) to represent the shared "legacy foreign key" fields. For instance, given the three table relationship:

    Person [one-to-many] ---> PersonAddress [many-to-one] ---> Address
 

and the following multi-table join in Progress

    for each person,
        each person-address of person,
        each address of person-address:
       ...
 

the first join (person-address of person) is represented as follows:

    personAddress.siteId = ? and personAddress.empNum = ?
 

where PersonAddress is the local DMO and Person the foreign DMO; and the second join (address of person-address) is represented as follows:

    address.addrId = ?
 

where Address is the local DMO and PersonAddress the foreign DMO.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static interface	DynamicLegacyKeyJoin.ParameterResolver An internal API used by this class to abstract the resolution of the query substitution parameters at query execution time.

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.List<FieldReference>	parameters List of field reference substitution parameters which define this join
private DynamicLegacyKeyJoin.ParameterResolver	resolver An object which resolves the substitution parameters

Fields inherited from class com.goldencode.p2j.persist.AbstractJoin

inverse, NOT_NULL_FIELD, NULL_FIELD

Constructor Summary

Constructors

Constructor and Description
DynamicLegacyKeyJoin(RecordBuffer local, RecordBuffer inverse) Constructor.

Method Summary

Modifier and Type	Method and Description
protected FQLExpression[][]	generateFQL(RecordBuffer local, RecordBuffer inverse, RelationInfo info, boolean dereference) Generate the FQL where clause snippets which will be inserted into the overall FQL statement executed by the enclosing query.
(package private) java.util.List<java.io.Serializable>	getParameters() Get the values of DMO instance fields which will be used as the query substitution parameters.
protected java.util.List<FqlType>	getParameterTypes(RelationInfo info, boolean dereference) Get the values of DMO instance fields which will be used as the query substitution parameters.
java.util.List<FieldReference>	getUnresolvedParameters() Get a list of unresolved field reference parameters for this join.
protected boolean	isServerJoin() Report whether the join represented by this object takes place at the database server, or within runtime code.
protected void	setup(RecordBuffer local, RecordBuffer inverse, RelationInfo info, boolean dereference) Perform additional setup necessary to create the object which will resolve the query substitution parameters at query execution time.

Methods inherited from class com.goldencode.p2j.persist.AbstractJoin

getFQL, getInverse, getInverseInterface, getParameterTypes, raiseJoinError

Methods inherited from class java.lang.Object

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

Field Detail

resolver

private DynamicLegacyKeyJoin.ParameterResolver resolver

An object which resolves the substitution parameters

parameters

private java.util.List<FieldReference> parameters

List of field reference substitution parameters which define this join

Constructor Detail

DynamicLegacyKeyJoin

DynamicLegacyKeyJoin(RecordBuffer local,
                     RecordBuffer inverse)

Constructor.

Parameters:

local - Local record buffer (the referring end of the join).

inverse - Inverse record buffer (the referent end of the join).

Method Detail

getUnresolvedParameters

public java.util.List<FieldReference> getUnresolvedParameters()

Get a list of unresolved field reference parameters for this join.

Overrides:

getUnresolvedParameters in class AbstractJoin

Returns:

The list of unresolved field reference substitution parameters which define the join between the local buffer and its inverse.

isServerJoin

protected boolean isServerJoin()

Report whether the join represented by this object takes place at the database server, or within runtime code.

Specified by:

isServerJoin in class AbstractJoin

Returns:

true if the join happens at the server; false if it happens in the runtime.

generateFQL

protected FQLExpression[][] generateFQL(RecordBuffer local,
                                        RecordBuffer inverse,
                                        RelationInfo info,
                                        boolean dereference)

Generate the FQL where clause snippets which will be inserted into the overall FQL statement executed by the enclosing query. See the class description for additional details on the composition of the clause.

Specified by:

generateFQL in class AbstractJoin

Parameters:

local - Local record buffer (the referring end of the join).

inverse - Inverse record buffer (the referent end of the join).

info - Relation descriptor object.

dereference - true if the local DMO contains a reference to the foreign record, which must be dereferenced in the FQL query; false if the local DMO is the foreign record, referenced by the inverse DMO.

Returns:

FQL where clause snippet which expresses the join.

getParameterTypes

protected java.util.List<FqlType> getParameterTypes(RelationInfo info,
                                                    boolean dereference)

Get the values of DMO instance fields which will be used as the query substitution parameters.

Specified by:

getParameterTypes in class AbstractJoin

Parameters:

info - Relation descriptor object.

dereference - true if the local DMO contains a reference to the foreign record, which must be dereferenced in the FQL query; false if the local DMO is the foreign record, referenced by the inverse DMO.

Returns:

The appropriate types for the query substitution parameters is used for this join.

setup

protected void setup(RecordBuffer local,
                     RecordBuffer inverse,
                     RelationInfo info,
                     boolean dereference)

Perform additional setup necessary to create the object which will resolve the query substitution parameters at query execution time.

Overrides:

setup in class AbstractJoin

Parameters:

local - Local record buffer (the refering end of the join).

inverse - Inverse record buffer (the referent end of the join).

info - Relation descriptor object.

dereference - true if the local DMO contains a reference to the foreign record, which must be dereferenced in the FQL query; false if the local DMO is the foreign record, referenced by the inverse DMO.

getParameters

java.util.List<java.io.Serializable> getParameters()

Get the values of DMO instance fields which will be used as the query substitution parameters. Utilizes the inner helper class DynamicLegacyKeyJoin.ParameterResolver to do its work.

Overrides:

getParameters in class AbstractJoin

Returns:

A list of query substitution parameters.