package org.qi4j.runtime.value;
import org.qi4j.api.association.AssociationStateHolder;
import org.qi4j.api.common.ConstructionException;
import org.qi4j.api.value.ValueBuilder;
import org.qi4j.runtime.structure.ModelModule;
import org.qi4j.runtime.structure.ModuleInstance;
public class ValueBuilderWithState<T> implements ValueBuilder<T>
{
private final ModelModule<ValueModel> model;
private ValueInstance prototypeInstance;
public ValueBuilderWithState( ModelModule<ValueModel> compositeModelModule, ModuleInstance currentModule, ValueStateModel.StateResolver stateResolver ) {
ValueStateInstance state = new ValueStateInstance( compositeModelModule, currentModule, stateResolver );
ValueInstance instance = compositeModelModule.model().newValueInstance( compositeModelModule.module(), state );
instance.prepareToBuild();
this.model = compositeModelModule;
this.prototypeInstance = instance;
}
@Override
public T prototype()
{
verifyUnderConstruction();
return prototypeInstance.<T>proxy();
}
@Override
public AssociationStateHolder state()
{
verifyUnderConstruction();
return prototypeInstance.state();
}
@Override
public <K> K prototypeFor( Class<K> mixinType )
{
verifyUnderConstruction();
return prototypeInstance.newProxy( mixinType );
}
@Override
public T newInstance()
throws ConstructionException
{
verifyUnderConstruction();
// Set correct info's (immutable) on the state
prototypeInstance.prepareBuilderState();
// Check that it is valid
model.model().checkConstraints( prototypeInstance.state() );
try
{
return prototypeInstance.<T>proxy();
}
finally
{
// Invalidate builder
prototypeInstance = null;
}
}
private void verifyUnderConstruction()
{
if( prototypeInstance == null )
{
throw new IllegalStateException( "ValueBuilder instances cannot be reused" );
}
}
}