com.db4o.config
Interface ObjectClass

public interface ObjectClass

configuration interface for classes.

Examples: ../com/db4o/samples/translators/Default.java.

Use the global Configuration object to configure db4o before opening an ObjectContainer.

Example:
Configuration config = Db4o.configure();
ObjectClass oc = config.objectClass("package.className");
oc.updateDepth(3);
oc.minimumActivationDepth(3);


Method Summary

void	cascadeOnActivate(boolean flag) sets cascaded activation behaviour.
void	cascadeOnDelete(boolean flag) sets cascaded delete behaviour.
void	cascadeOnUpdate(boolean flag) sets cascaded update behaviour.
void	maximumActivationDepth(int depth) sets the maximum activation depth to the desired value.
void	minimumActivationDepth(int depth) sets the minimum activation depth to the desired value.
ObjectField	objectField(java.lang.String fieldName) returns an ObjectField object to configure the specified field.
void	rename(java.lang.String newName) renames a stored class.
void	storeTransientFields(boolean flag) allows to specify if transient fields are to be stored.
void	translate(ObjectTranslator translator) registers a translator for this class.
void	updateDepth(int depth) specifies the updateDepth for this class.

Method Detail

cascadeOnActivate

public void cascadeOnActivate(boolean flag)

sets cascaded activation behaviour.

Setting cascadeOnActivate to true will result in the activation of all member objects if an instance of this class is activated.

The default setting is false.

Parameters:

flag - whether activation is to be cascaded to member objects.

See Also:

ObjectField#cascadeOnActivate(), ObjectContainer#activate(),
Using callbacks, Why activation?

cascadeOnDelete

public void cascadeOnDelete(boolean flag)

sets cascaded delete behaviour.

Setting cascadeOnDelete to true will result in the deletion of all member objects of instances of this class, if they are passed to ObjectContainer#delete().

Caution !
This setting will also trigger deletion of old member objects, on calls to ObjectContainer#set().

An example of the behaviour:
ObjectContainer con;
Bar bar1 = new Bar();
Bar bar2 = new Bar();
foo.bar = bar1;
con.set(foo); // bar1 is stored as a member of foo
foo.bar = bar2;
con.set(foo); // bar2 is stored as a member of foo
The last statement will also delete bar2 from the ObjectContainer, no matter how many other stored objects hold references to bar2.

The default setting is false.

Parameters:

flag - whether deletes are to be cascaded to member objects.

See Also:

ObjectField#cascadeOnDelete(), ObjectContainer#delete(),
Using callbacks

cascadeOnUpdate

public void cascadeOnUpdate(boolean flag)

sets cascaded update behaviour.

Setting cascadeOnUpdate to true will result in the update of all member objects if a stored instance of this class is passed to ObjectContainer#set().

The default setting is false.

Parameters:

flag - whether updates are to be cascaded to member objects.

See Also:

ObjectField#cascadeOnUpdate(), ObjectContainer#set(),
Using callbacks

maximumActivationDepth

public void maximumActivationDepth(int depth)

sets the maximum activation depth to the desired value.

A class specific setting overrides the global setting.

Parameters:

depth - the desired maximum activation depth

See Also:

Why activation?, ObjectClass#cascadeOnActivate()

minimumActivationDepth

public void minimumActivationDepth(int depth)

sets the minimum activation depth to the desired value.

A class specific setting overrides the global setting.

Parameters:

depth - the desired minimum activation depth

See Also:

Why activation?, ObjectClass#cascadeOnActivate()

objectField

public ObjectField objectField(java.lang.String fieldName)

returns an ObjectField object to configure the specified field.

Parameters:

fieldName - the fieldname of the field to be configured.

Returns:

an instance of an ObjectField object for configuration.

rename

public void rename(java.lang.String newName)

renames a stored class.

Use this method to refactor classes.

Examples: ../com/db4o/samples/rename.

This feature is not available in db4o community edition.

Parameters:

newName - the new fully qualified classname.

storeTransientFields

public void storeTransientFields(boolean flag)

allows to specify if transient fields are to be stored.
The default for every class is false.

Parameters:

flag - whether or not transient fields are to be stored.

translate

public void translate(ObjectTranslator translator)

registers a translator for this class.

Examples: ../com/db4o/samples/translators.

Parameters:

translator - this may be an ObjectTranslator or an ObjectConstructor

See Also:

ObjectTranslator, ObjectConstructor

updateDepth

public void updateDepth(int depth)

specifies the updateDepth for this class.

see the documentation of ObjectContainer.set() for further details.

The default setting is 0: Only the object passed to ObjectContainer.set() will be updated.

Parameters:

depth - the depth of the desired update for this class.

See Also:

Configuration#updateDepth(), ObjectClass#cascadeOnUpdate(), ObjectField#cascadeOnUpdate(),
Using callbacks