org.apache.cayenne

Interface ValueHolder<E>

All Superinterfaces:

Serializable

All Known Implementing Classes:

IndexPropertyList, PersistentObjectHolder, PersistentObjectList, PersistentObjectMap, PersistentObjectSet, ToManyList, ToManySet

public interface ValueHolder<E>
extends Serializable

Provides a level of indirection for property value access, most often used for deferred faulting of to-one relationships. A ValueHolder abstracts how a property value is obtained (fetched from DB, etc.), thus simplifying design of an object that uses it.

Here is an example of a bean property implemented using ValueHolder:

 protected ValueHolder someProperty;
 
 public SomeClass getSomeProperty() {
     return (SomeClass) somePropertyHolder.getValue(SomeClass.class);
 }
 
 public void setSomeProperty(SomeClass newValue) {
     somePropertyHolder.setValue(SomeClass.class, newValue);
 }
 

Since:

1.2

Method Summary

Modifier and Type	Method and Description
E	getValue() Returns an object stored by this ValueHolder.
E	getValueDirectly() Retrieves ValueHolder value without triggering fault resolution.
void	invalidate() Turns a ValueHolder into a fault.
boolean	isFault() Returns true if the internal value is not yet resolved.
E	setValue(E value) Sets an object stored by this ValueHolder.
E	setValueDirectly(E value) Sets ValueHolder vaue without triggering fault resolution.

Method Detail

getValue

E getValue()
    throws CayenneRuntimeException

Returns an object stored by this ValueHolder.

Throws:

CayenneRuntimeException

getValueDirectly

E getValueDirectly()
            throws CayenneRuntimeException

Retrieves ValueHolder value without triggering fault resolution.

Throws:

CayenneRuntimeException

setValue

E setValue(E value)
    throws CayenneRuntimeException

Sets an object stored by this ValueHolder.

Parameters:

value - a new value of the ValueHolder.

Returns:

a previous value saved in the ValueHolder.

Throws:

CayenneRuntimeException

setValueDirectly

E setValueDirectly(E value)
            throws CayenneRuntimeException

Sets ValueHolder vaue without triggering fault resolution.

Throws:

CayenneRuntimeException

isFault

boolean isFault()

Returns true if the internal value is not yet resolved.

invalidate

void invalidate()

Turns a ValueHolder into a fault.