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1 package org.apache.ojb.broker.accesslayer;
2
3
17
18 import java.lang.reflect.Array  ;
19 import java.util.ArrayList ;
20 import java.util.Collection ;
21 import java.util.HashMap ;
22 import java.util.HashSet ;
23 import java.util.Iterator ;
24 import java.util.List ;
25
26 import org.apache.ojb.broker.Identity;
27 import org.apache.ojb.broker.ManageableCollection;
28 import org.apache.ojb.broker.OJBRuntimeException;
29 import org.apache.ojb.broker.PersistenceBroker;
30 import org.apache.ojb.broker.IdentityFactory;
31 import org.apache.ojb.broker.core.PersistenceBrokerImpl;
32 import org.apache.ojb.broker.core.proxy.CollectionProxyDefaultImpl;
33 import org.apache.ojb.broker.core.proxy.ProxyHelper;
34 import org.apache.ojb.broker.metadata.ClassDescriptor;
35 import org.apache.ojb.broker.metadata.CollectionDescriptor;
36 import org.apache.ojb.broker.metadata.FieldHelper;
37 import org.apache.ojb.broker.metadata.MetadataException;
38 import org.apache.ojb.broker.metadata.ObjectReferenceDescriptor;
39 import org.apache.ojb.broker.metadata.fieldaccess.PersistentField;
40 import org.apache.ojb.broker.query.Query;
41 import org.apache.ojb.broker.query.QueryByCriteria;
42 import org.apache.ojb.broker.util.BrokerHelper;
43 import org.apache.ojb.broker.util.collections.RemovalAwareCollection;
44 import org.apache.ojb.broker.util.collections.RemovalAwareList;
45 import org.apache.ojb.broker.util.collections.RemovalAwareSet;
46
47
53 public class CollectionPrefetcher extends RelationshipPrefetcherImpl
54 {
55
56
62 public CollectionPrefetcher(PersistenceBrokerImpl aBroker, ObjectReferenceDescriptor anOrd)
63 {
64 super(aBroker, anOrd);
65 }
66
67
72 protected Query[] buildPrefetchQueries(Collection owners, Collection children)
73 {
74 ClassDescriptor cld = getOwnerClassDescriptor();
75 Class topLevelClass = getBroker().getTopLevelClass(cld.getClassOfObject());
76 BrokerHelper helper = getBroker().serviceBrokerHelper();
77 Collection queries = new ArrayList (owners.size());
78 Collection idsSubset = new HashSet (owners.size());
79 Object [] fkValues;
80 Object owner;
81 Identity id;
82
83 Iterator iter = owners.iterator();
84 while (iter.hasNext())
85 {
86 owner = iter.next();
87 fkValues = helper.extractValueArray(helper.getKeyValues(cld, owner));
88 id = getBroker().serviceIdentity().buildIdentity(null, topLevelClass, fkValues);
89 idsSubset.add(id);
90 if (idsSubset.size() == pkLimit)
91 {
92 queries.add(buildPrefetchQuery(idsSubset));
93 idsSubset.clear();
94 }
95 }
96
97 if (idsSubset.size() > 0)
98 {
99 queries.add(buildPrefetchQuery(idsSubset));
100 }
101
102 return (Query[]) queries.toArray(new Query[queries.size()]);
103 }
104
105
110 protected Query buildPrefetchQuery(Collection ids)
111 {
112 CollectionDescriptor cds = getCollectionDescriptor();
113 QueryByCriteria query = buildPrefetchQuery(ids, cds.getForeignKeyFieldDescriptors(getItemClassDescriptor()));
114
115 if (!cds.getOrderBy().isEmpty())
117 {
118 Iterator iter = cds.getOrderBy().iterator();
119 while (iter.hasNext())
120 {
121 query.addOrderBy((FieldHelper) iter.next());
122 }
123 }
124
125 return query;
126 }
127
128
131 protected void associateBatched(Collection owners, Collection children)
132 {
133 CollectionDescriptor cds = getCollectionDescriptor();
134 PersistentField field = cds.getPersistentField();
135 PersistenceBroker pb = getBroker();
136 Class ownerTopLevelClass = pb.getTopLevelClass(getOwnerClassDescriptor().getClassOfObject());
137 Class collectionClass = cds.getCollectionClass(); HashMap ownerIdsToLists = new HashMap (owners.size());
139
140 IdentityFactory identityFactory = pb.serviceIdentity();
141 for (Iterator it = owners.iterator(); it.hasNext();)
143 {
144 Object owner = it.next();
145 ownerIdsToLists.put(identityFactory.buildIdentity(getOwnerClassDescriptor(), owner), new ArrayList ());
146 }
147
148 for (Iterator it = children.iterator(); it.hasNext();)
150 {
151 Object child = it.next();
152 ClassDescriptor cld = getDescriptorRepository().getDescriptorFor(ProxyHelper.getRealClass(child));
154
155 Object [] fkValues = cds.getForeignKeyValues(child, cld);
156 Identity ownerId = identityFactory.buildIdentity(null, ownerTopLevelClass, fkValues);
157 List list = (List ) ownerIdsToLists.get(ownerId);
158 if (list != null)
159 {
160 list.add(child);
161 }
162 }
163
164 for (Iterator it = owners.iterator(); it.hasNext();)
166 {
167 Object result;
168 Object owner = it.next();
169 Identity ownerId = identityFactory.buildIdentity(owner);
170 List list = (List ) ownerIdsToLists.get(ownerId);
171
172 if ((collectionClass == null) && field.getType().isArray())
173 {
174 int length = list.size();
175 Class itemtype = field.getType().getComponentType();
176 result = Array.newInstance(itemtype, length);
177 for (int j = 0; j < length; j++)
178 {
179 Array.set(result, j, list.get(j));
180 }
181 }
182 else
183 {
184 ManageableCollection col = createCollection(cds, collectionClass);
185 for (Iterator it2 = list.iterator(); it2.hasNext();)
186 {
187 col.ojbAdd(it2.next());
188 }
189 result = col;
190 }
191
192 Object value = field.get(owner);
193 if ((value instanceof CollectionProxyDefaultImpl) && (result instanceof Collection ))
194 {
195 ((CollectionProxyDefaultImpl) value).setData((Collection ) result);
196 }
197 else
198 {
199 field.set(owner, result);
200 }
201 }
202 }
203
204
213 protected ManageableCollection createCollection(CollectionDescriptor desc, Class collectionClass)
214 {
215 Class fieldType = desc.getPersistentField().getType();
216 ManageableCollection col;
217
218 if (collectionClass == null)
219 {
220 if (ManageableCollection.class.isAssignableFrom(fieldType))
221 {
222 try
223 {
224 col = (ManageableCollection)fieldType.newInstance();
225 }
226 catch (Exception e)
227 {
228 throw new OJBRuntimeException("Cannot instantiate the default collection type "+fieldType.getName()+" of collection "+desc.getAttributeName()+" in type "+desc.getClassDescriptor().getClassNameOfObject());
229 }
230 }
231 else if (fieldType.isAssignableFrom(RemovalAwareCollection.class))
232 {
233 col = new RemovalAwareCollection();
234 }
235 else if (fieldType.isAssignableFrom(RemovalAwareList.class))
236 {
237 col = new RemovalAwareList();
238 }
239 else if (fieldType.isAssignableFrom(RemovalAwareSet.class))
240 {
241 col = new RemovalAwareSet();
242 }
243 else
244 {
245 throw new MetadataException("Cannot determine a default collection type for collection "+desc.getAttributeName()+" in type "+desc.getClassDescriptor().getClassNameOfObject());
246 }
247 }
248 else
249 {
250 try
251 {
252 col = (ManageableCollection)collectionClass.newInstance();
253 }
254 catch (Exception e)
255 {
256 throw new OJBRuntimeException("Cannot instantiate the collection class "+collectionClass.getName()+" of collection "+desc.getAttributeName()+" in type "+desc.getClassDescriptor().getClassNameOfObject());
257 }
258 }
259 return col;
260 }
261
262 protected CollectionDescriptor getCollectionDescriptor()
263 {
264 return (CollectionDescriptor) getObjectReferenceDescriptor();
265 }
266 }
267 |
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