Oracle Application Server TopLink API Reference
10g Release 2 (10.1.2)

B15903-01


oracle.toplink.publicinterface
Class InheritancePolicy

java.lang.Object
  extended byoracle.toplink.publicinterface.InheritancePolicy

All Implemented Interfaces:
java.lang.Cloneable, java.io.Serializable

public class InheritancePolicy
extends java.lang.Object
implements java.io.Serializable, java.lang.Cloneable

Purpose: Allows customization of an object's inheritance.

See Also:
Serialized Form

Method Summary
void addClassIndicator(java.lang.Class childClass, java.lang.Object typeValue)
PUBLIC: Add a class indicator for the root classes subclass.
void dontReadSubclassesOnQueries()
PUBLIC: Set the descriptor to only read instance of itself when queried.
void dontUseClassNameAsIndicator()
PUBLIC: Set the descriptor not to use the class' full name as the indicator.
java.lang.String getClassExtractionMethodName()
PUBLIC: A class extraction method can be registered with the descriptor to override the default inheritance mechanism.
java.util.Vector getClassIndicatorAssociations()
PUBLIC: Set the class indicator associations.
java.lang.String getClassIndicatorFieldName()
PUBLIC: Return the class indicator field name.
Expression getOnlyInstancesExpression()
PUBLIC: REturn the 'only instances expression'.
java.lang.Class getParentClass()
PUBLIC: Return the parent class.
java.lang.String getReadAllSubclassesViewName()
PUBLIC: The view can be used to optimize/customize the query for all subclasses where they have multiple tables.
Expression getWithAllSubclassesExpression()
PUBLIC: Return the Expression which gets all subclasses.
void readSubclassesOnQueries()
PUBLIC: Set the descriptor to read instance of itself and its subclasses when queried.
void setAlwaysUseOuterJoinForClassType(boolean choice)
PUBLIC: Sets the inheritance policy to always use an outer join when quering across a relationship of class.
void setClassExtractionMethodName(java.lang.String staticClassClassExtractionMethod)
PUBLIC: A class extraction method can be registered with the descriptor to override the default inheritance mechanism.
void setClassIndicatorAssociations(java.util.Vector classIndicatorAssociations)
PUBLIC: Set the class indicator associations.
void setClassIndicatorFieldName(java.lang.String fieldName)
PUBLIC: To set the class indicator field name.
void setClassIndicatorMapping(java.util.Hashtable classIndicatorMapping)
PUBLIC: Set the association of indicators and classes.
void setOnlyInstancesExpression(Expression onlyInstancesExpression)
PUBLIC: Sets the expression used to select instance of the class only.
void setParentClass(java.lang.Class parentClass)
PUBLIC: Set the parent class.
void setReadAllSubclassesViewName(java.lang.String readAllSubclassesViewName)
PUBLIC: The view can be used to optimize/customize the query for all subclasses where they have multiple tables.
void setShouldReadSubclasses(boolean shouldReadSubclasses)
PUBLIC: Set the descriptor to read instance of itself and its subclasses when queried.
void setShouldReadSubclasses(java.lang.Boolean shouldReadSubclasses)
PUBLIC: Set the descriptor to read instance of itself and its subclasses when queried.
void setShouldUseClassNameAsIndicator(boolean shouldUseClassNameAsIndicator)
PUBLIC: Set if the descriptor uses the classes fully qualified name as the indicator.
void setWithAllSubclassesExpression(Expression withAllSubclassesExpression)
PUBLIC: Sets the expression to be used for querying for a class and all its subclasses.
boolean shouldAlwaysUseOuterJoin()
PUBLIC: returns if the inheritance policy will always use an outerjoin when selecting class type
boolean shouldReadSubclasses()
PUBLIC: Return true if this descriptor should read instances of itself and subclasses on queries.
java.lang.Boolean shouldReadSubclassesValue()
PUBLIC: Return true if this descriptor should read instances of itself and subclasses on queries.
boolean shouldUseClassNameAsIndicator()
PUBLIC: Return true if the descriptor use the classes full name as the indicator.
void useClassNameAsIndicator()
PUBLIC: Set the descriptor to use the classes full name as the indicator.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

addClassIndicator

public void addClassIndicator(java.lang.Class childClass,
                              java.lang.Object typeValue)
PUBLIC: Add a class indicator for the root classes subclass. The indicator is used to determine the class to use for a row read from the database, and to query only instances of a class from the database. Every concrete persistent subclass must have a single unique indicator defined for it. If the root class is concrete then it must also define an indicator. Only the root class's descriptor of the entire inheritance hierarchy can define the class indicator mapping.

dontReadSubclassesOnQueries

public void dontReadSubclassesOnQueries()
PUBLIC: Set the descriptor to only read instance of itself when queried. This is used with inheritance to configure the result of queries. By default this is true for root inheritance descriptors, and false for all others.

dontUseClassNameAsIndicator

public void dontUseClassNameAsIndicator()
PUBLIC: Set the descriptor not to use the class' full name as the indicator. The class indicator is used with inheritance to determine the class from a row. By default a class indicator mapping is required, this can be set to true if usage of the class name is desired. The field must be of a large enough size to store the fully qualified class name.

getClassExtractionMethodName

public java.lang.String getClassExtractionMethodName()
PUBLIC: A class extraction method can be registered with the descriptor to override the default inheritance mechanism. This allows for the class indicator field to not be used, and a user defined one instead. The method registered must be a static method on the class that the descriptor is for, the method must take DatabaseRow as argument, and must return the class to use for that row. This method will be used to decide which class to instantiate when reading from the database. It is the application's responsiblity to populate any typing information in the database required to determine the class from the row. If this method is used then the class indicator field and mapping cannot be used, also the descriptor's withAllSubclasses and onlyInstances expressions must also be setup correctly.
See Also:
setWithAllSubclassesExpression(Expression), setOnlyInstancesExpression(Expression)

getClassIndicatorAssociations

public java.util.Vector getClassIndicatorAssociations()
PUBLIC: Set the class indicator associations.

getClassIndicatorFieldName

public java.lang.String getClassIndicatorFieldName()
PUBLIC: Return the class indicator field name. This is the name of the field in the table that stores what type of object this is.

getOnlyInstancesExpression

public Expression getOnlyInstancesExpression()
PUBLIC: REturn the 'only instances expression'.

getParentClass

public java.lang.Class getParentClass()
PUBLIC: Return the parent class.

getReadAllSubclassesViewName

public java.lang.String getReadAllSubclassesViewName()
PUBLIC: The view can be used to optimize/customize the query for all subclasses where they have multiple tables. This view can use outer joins or unions to combine the results of selecting from all of the subclass tables. If a view is not given then TopLink must make an individual call for each subclass.

getWithAllSubclassesExpression

public Expression getWithAllSubclassesExpression()
PUBLIC: Return the Expression which gets all subclasses.

readSubclassesOnQueries

public void readSubclassesOnQueries()
PUBLIC: Set the descriptor to read instance of itself and its subclasses when queried. This is used with inheritance to configure the result of queries. By default this is true for root inheritance descriptors, and false for all others.

setClassExtractionMethodName

public void setClassExtractionMethodName(java.lang.String staticClassClassExtractionMethod)
PUBLIC: A class extraction method can be registered with the descriptor to override the default inheritance mechanism. This allows for the class indicator field to not be used, and a user defined one instead. The method registered must be a static method on the class that the descriptor is for, the method must take DatabaseRow as argument, and must return the class to use for that row. This method will be used to decide which class to instantiate when reading from the database. It is the application's responsiblity to populate any typing information in the database required to determine the class from the row. If this method is used then the class indicator field and mapping cannot be used, also the descriptor's withAllSubclasses and onlyInstances expressions must also be setup correctly.
See Also:
setWithAllSubclassesExpression(Expression), setOnlyInstancesExpression(Expression)

setClassIndicatorAssociations

public void setClassIndicatorAssociations(java.util.Vector classIndicatorAssociations)
PUBLIC: Set the class indicator associations.

setClassIndicatorFieldName

public void setClassIndicatorFieldName(java.lang.String fieldName)
PUBLIC: To set the class indicator field name. This is the name of the field in the table that stores what type of object this is.

setClassIndicatorMapping

public void setClassIndicatorMapping(java.util.Hashtable classIndicatorMapping)
PUBLIC: Set the association of indicators and classes. This may be desired to be used by clients in strange inheritence models.

setOnlyInstancesExpression

public void setOnlyInstancesExpression(Expression onlyInstancesExpression)
PUBLIC: Sets the expression used to select instance of the class only. Can be used to customize the inheritance class indicator expression.

setParentClass

public void setParentClass(java.lang.Class parentClass)
PUBLIC: Set the parent class. A descriptor can inherit from another descriptor through defining it as its parent. The root descriptor must define a class indicator field and mapping. All children must share the same table as their parent but can add additional tables. All children must share the root descriptor primary key.

setReadAllSubclassesViewName

public void setReadAllSubclassesViewName(java.lang.String readAllSubclassesViewName)
PUBLIC: The view can be used to optimize/customize the query for all subclasses where they have multiple tables. This view can use outer joins or unions to combine the results of selecting from all of the subclass tables. If a view is not given then TopLink must make an individual call for each subclass.

setShouldReadSubclasses

public void setShouldReadSubclasses(java.lang.Boolean shouldReadSubclasses)
PUBLIC: Set the descriptor to read instance of itself and its subclasses when queried. This is used with inheritence to configure the result of queries. By default this is true for root inheritence descriptors, and false for all others.

setShouldReadSubclasses

public void setShouldReadSubclasses(boolean shouldReadSubclasses)
PUBLIC: Set the descriptor to read instance of itself and its subclasses when queried. This is used with inheritence to configure the result of queries. By default this is true for root inheritence descriptors, and false for all others.

setShouldUseClassNameAsIndicator

public void setShouldUseClassNameAsIndicator(boolean shouldUseClassNameAsIndicator)
PUBLIC: Set if the descriptor uses the classes fully qualified name as the indicator. The class indicator is used with inheritence to determine the class from a row. By default a class indicator mapping is required, this can be set to true if usage of the class name is desired. The field must be of a large enough size to store the fully qualified class name.

setAlwaysUseOuterJoinForClassType

public void setAlwaysUseOuterJoinForClassType(boolean choice)
PUBLIC: Sets the inheritance policy to always use an outer join when quering across a relationship of class. used when using getAllowingNull(), or anyOfAllowingNone()

setWithAllSubclassesExpression

public void setWithAllSubclassesExpression(Expression withAllSubclassesExpression)
PUBLIC: Sets the expression to be used for querying for a class and all its subclasses. Can be used to customize the inheritence class indicator expression.

shouldReadSubclasses

public boolean shouldReadSubclasses()
PUBLIC: Return true if this descriptor should read instances of itself and subclasses on queries.

shouldReadSubclassesValue

public java.lang.Boolean shouldReadSubclassesValue()
PUBLIC: Return true if this descriptor should read instances of itself and subclasses on queries.

shouldAlwaysUseOuterJoin

public boolean shouldAlwaysUseOuterJoin()
PUBLIC: returns if the inheritance policy will always use an outerjoin when selecting class type

shouldUseClassNameAsIndicator

public boolean shouldUseClassNameAsIndicator()
PUBLIC: Return true if the descriptor use the classes full name as the indicator. The class indicator is used with inheritance to determine the class from a row. By default a class indicator mapping is required, this can be set to true if usage of the class name is desired. The field must be of a large enough size to store the fully qualified class name.

useClassNameAsIndicator

public void useClassNameAsIndicator()
PUBLIC: Set the descriptor to use the classes full name as the indicator. The class indicator is used with inheritance to determine the class from a row. By default a class indicator mapping is required, this can be set to true if usage of the class name is desired. The field must be of a large enough size to store the fully qualified class name.

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