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1
19
20 package org.apache.cayenne;
21
22 import java.util.ArrayList  ;
23 import java.util.Collection ;
24 import java.util.Collections ;
25 import java.util.Iterator ;
26
27 import org.apache.cayenne.map.DeleteRule;
28 import org.apache.cayenne.map.ObjEntity;
29 import org.apache.cayenne.map.ObjRelationship;
30 import org.apache.cayenne.reflect.ArcProperty;
31 import org.apache.cayenne.reflect.AttributeProperty;
32 import org.apache.cayenne.reflect.ClassDescriptor;
33 import org.apache.cayenne.reflect.Property;
34 import org.apache.cayenne.reflect.PropertyVisitor;
35 import org.apache.cayenne.reflect.ToManyProperty;
36 import org.apache.cayenne.reflect.ToOneProperty;
37
38
44 class ObjectContextDeleteAction {
45
46 private ObjectContext context;
47
48 ObjectContextDeleteAction(ObjectContext context) {
49 this.context = context;
50 }
51
52 boolean performDelete(Persistent object) throws DeleteDenyException {
53
54 int oldState = object.getPersistenceState();
55
56 if (oldState == PersistenceState.TRANSIENT
57 || oldState == PersistenceState.DELETED) {
58 return false;
59 }
60
61 if (object.getObjectContext() == null) {
62 throw new CayenneRuntimeException(
63 "Attempt to delete unregistered non-TRANSIENT object: " + object);
64 }
65
66 if (object.getObjectContext() != context) {
67 throw new CayenneRuntimeException(
68 "Attempt to delete object regsitered in a different ObjectContext. Object: "
69 + object
70 + ", context: "
71 + context);
72 }
73
74 if (oldState == PersistenceState.NEW) {
75 deleteNew(object);
76 }
77 else {
78 deletePersistent(object);
79 }
80
81 return true;
82 }
83
84 private void deleteNew(Persistent object) {
85 object.setPersistenceState(PersistenceState.TRANSIENT);
86 processDeleteRules(object, PersistenceState.NEW);
87 context.getGraphManager().unregisterNode(object.getObjectId());
88 }
89
90 private void deletePersistent(Persistent object) {
91 int oldState = object.getPersistenceState();
92 object.setPersistenceState(PersistenceState.DELETED);
93 processDeleteRules(object, oldState);
94 context.getGraphManager().nodeRemoved(object.getObjectId());
95 }
96
97 private void processDeleteRules(final Persistent object, final int oldState) {
98
99 String entityName = object.getObjectId().getEntityName();
100 final ObjEntity entity = context.getEntityResolver().getObjEntity(entityName);
101 ClassDescriptor descriptor = context.getEntityResolver().getClassDescriptor(
102 entityName);
103
104 descriptor.visitProperties(new PropertyVisitor() {
105
106 public boolean visitToMany(ToManyProperty property) {
107 ObjRelationship relationship = (ObjRelationship) entity
108 .getRelationship(property.getName());
109
110 processRules(object, property, relationship.getDeleteRule(), oldState);
111 return true;
112 }
113
114 public boolean visitToOne(ToOneProperty property) {
115 ObjRelationship relationship = (ObjRelationship) entity
116 .getRelationship(property.getName());
117
118 processRules(object, property, relationship.getDeleteRule(), oldState);
119 return true;
120 }
121
122 public boolean visitAttribute(AttributeProperty property) {
123 return true;
124 }
125 });
126 }
127
128 private void processRules(
129 Persistent object,
130 ArcProperty property,
131 int deleteRule,
132 int oldState) {
133
134 if (deleteRule == DeleteRule.NO_ACTION) {
135 return;
136 }
137
138 Collection relatedObjects = relatedObjects(object, property);
139 if (relatedObjects.isEmpty()) {
140 return;
141 }
142
143 switch (deleteRule) {
144
145 case DeleteRule.DENY:
146 object.setPersistenceState(oldState);
147 String message = relatedObjects.size() == 1
148 ? "1 related object"
149 : relatedObjects.size() + " related objects";
150 throw new DeleteDenyException(object, property.getName(), message);
151
152 case DeleteRule.NULLIFY:
153 ArcProperty reverseArc = property.getComplimentaryReverseArc();
154
155 if (reverseArc != null) {
156
157 if (reverseArc instanceof ToManyProperty) {
158 Iterator iterator = relatedObjects.iterator();
159 while (iterator.hasNext()) {
160 Object relatedObject = iterator.next();
161 ((ToManyProperty) reverseArc).removeTarget(
162 relatedObject,
163 object,
164 true);
165 }
166 }
167 else {
168 Iterator iterator = relatedObjects.iterator();
169 while (iterator.hasNext()) {
170 Object relatedObject = iterator.next();
171 ((ToOneProperty) reverseArc).setTarget(
172 relatedObject,
173 null,
174 true);
175 }
176 }
177 }
178
179 break;
180 case DeleteRule.CASCADE:
181
182 Iterator iterator = relatedObjects.iterator();
183 while (iterator.hasNext()) {
184 Persistent relatedObject = (Persistent) iterator.next();
185
186 performDelete(relatedObject);
189 }
190
191 break;
192 default:
193 object.setPersistenceState(oldState);
194 throw new CayenneRuntimeException("Invalid delete rule: " + deleteRule);
195 }
196 }
197
198 private Collection relatedObjects(Object object, Property property) {
199 Object related = property.readProperty(object);
200
201 if (related == null) {
202 return Collections.EMPTY_LIST;
203 }
204 else if (property instanceof ToManyProperty) {
207 Collection relatedCollection = (Collection ) related;
208 return relatedCollection.isEmpty() ? Collections.EMPTY_LIST : new ArrayList (
209 relatedCollection);
210 }
211 else {
212 return Collections.singleton(related);
213 }
214 }
215 }
216 |
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