Method: DetachedInstanceMerger(UnitOfWork)

1: /*
2: * JOPA
3: * Copyright (C) 2024 Czech Technical University in Prague
4: *
5: * This library is free software; you can redistribute it and/or
6: * modify it under the terms of the GNU Lesser General Public
7: * License as published by the Free Software Foundation; either
8: * version 3.0 of the License, or (at your option) any later version.
9: *
10: * This library is distributed in the hope that it will be useful,
11: * but WITHOUT ANY WARRANTY; without even the implied warranty of
12: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13: * Lesser General Public License for more details.
14: *
15: * You should have received a copy of the GNU Lesser General Public
16: * License along with this library.
17: */
18: package cz.cvut.kbss.jopa.sessions;
19:
20: import cz.cvut.kbss.jopa.model.descriptors.Descriptor;
21: import cz.cvut.kbss.jopa.sessions.change.ChangeRecord;
22: import cz.cvut.kbss.jopa.sessions.change.ObjectChangeSet;
23: import cz.cvut.kbss.jopa.sessions.merge.DetachedValueMerger;
24: import cz.cvut.kbss.jopa.sessions.merge.ValueMerger;
25:
26: class DetachedInstanceMerger {
27:
28: private final ValueMerger valueMerger;
29:
30: DetachedInstanceMerger(UnitOfWork uow) {
31: this.valueMerger = new DetachedValueMerger(uow);
32: }
33:
34: /**
35: * Merges changes from the detached instance being merged into persistence context (clone in the specified change
36: * set) into the corresponding managed instance (original in the change set).
37: *
38: * @param changeSet Set of changes to apply to the managed instance
39: * @return Managed instance with changes merged into it
40: */
41: Object mergeChangesFromDetachedToManagedInstance(ObjectChangeSet changeSet, Descriptor descriptor) {
42: assert changeSet != null;
43: assert changeSet.getClone() != null;
44: final Object target = changeSet.getOriginal();
45: assert target != null;
46:
47: for (ChangeRecord change : changeSet.getChanges()) {
48: valueMerger.mergeValue(target, change, descriptor.getAttributeDescriptor(change.getAttribute()));
49: }
50: return target;
51: }
52: }