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1
56 package org.objectstyle.cayenne.access.util;
57
58 import java.util.ArrayList  ;
59 import java.util.HashMap ;
60 import java.util.HashSet ;
61 import java.util.Iterator ;
62 import java.util.List ;
63 import java.util.Map ;
64 import java.util.Set ;
65
66 import org.objectstyle.cayenne.CayenneException;
67 import org.objectstyle.cayenne.access.ResultIterator;
68 import org.objectstyle.cayenne.map.DbAttribute;
69 import org.objectstyle.cayenne.map.DbEntity;
70
71
82 public class DistinctResultIterator implements ResultIterator {
83
84 protected ResultIterator wrappedIterator;
85 protected Set fetchedIds;
86 protected Map nextDataRow;
87 protected DbEntity defaultEntity;
88 protected boolean readingIds;
89
90
96 public DistinctResultIterator(ResultIterator wrappedIterator, DbEntity defaultEntity)
97 throws CayenneException {
98 if (wrappedIterator == null) {
99 throw new CayenneException("Null wrapped iterator.");
100 }
101
102 if (defaultEntity == null) {
103 throw new CayenneException("Null defaultEntity.");
104 }
105
106 this.wrappedIterator = wrappedIterator;
107 this.defaultEntity = defaultEntity;
108 this.fetchedIds = new HashSet ();
109
110 checkNextRow();
111 }
112
113
116 public void close() throws CayenneException {
117 wrappedIterator.close();
118 }
119
120
123 public List dataRows(boolean close) throws CayenneException {
124 List list = new ArrayList ();
125
126 try {
127 while (this.hasNextRow()) {
128 list.add(this.nextDataRow());
129 }
130 return list;
131 }
132 finally {
133 if (close) {
134 this.close();
135 }
136 }
137 }
138
139 public int getDataRowWidth() {
140 return wrappedIterator.getDataRowWidth();
141 }
142
143 public boolean hasNextRow() throws CayenneException {
144 return nextDataRow != null;
145 }
146
147 public Map nextDataRow() throws CayenneException {
148 if (!hasNextRow()) {
149 throw new CayenneException(
150 "An attempt to read uninitialized row or past the end of the iterator.");
151 }
152
153 Map row = nextDataRow;
154 checkNextRow();
155 return row;
156 }
157
158
162 public Map nextObjectId(DbEntity entity) throws CayenneException {
163 if (!hasNextRow()) {
164 throw new CayenneException(
165 "An attempt to read uninitialized row or past the end of the iterator.");
166 }
167
168 Map row = nextDataRow;
169
170 if (!readingIds) {
172 Iterator it = row.entrySet().iterator();
173 while (it.hasNext()) {
174 Map.Entry entry = (Map.Entry ) it.next();
175 String name = (String ) entry.getKey();
176 DbAttribute attribute = (DbAttribute) entity.getAttribute(name);
177 if (attribute == null || !attribute.isPrimaryKey()) {
178 it.remove();
179 }
180 }
181 }
182
183 checkNextId(entity);
184 return row;
185 }
186
187 public void skipDataRow() throws CayenneException {
188 if (!hasNextRow()) {
189 throw new CayenneException(
190 "An attempt to read uninitialized row or past the end of the iterator.");
191 }
192
193 if (readingIds) {
194 checkNextId(defaultEntity);
195 }
196 else {
197 checkNextRow();
198 }
199 }
200
201 void checkNextRow() throws CayenneException {
202 if (readingIds) {
203 throw new CayenneException(
204 "Can't go back from reading ObjectIds to reading rows.");
205 }
206
207 nextDataRow = null;
208 while (wrappedIterator.hasNextRow()) {
209 Map next = wrappedIterator.nextDataRow();
210
211
215 Map id = new HashMap ();
216 Iterator it = defaultEntity.getPrimaryKey().iterator();
217 while (it.hasNext()) {
218 DbAttribute pk = (DbAttribute) it.next();
219 id.put(pk.getName(), next.get(pk.getName()));
220 }
221
222 if (fetchedIds.add(id)) {
223 this.nextDataRow = next;
224 break;
225 }
226 }
227 }
228
229 void checkNextId(DbEntity entity) throws CayenneException {
230 if (entity == null) {
231 throw new CayenneException("Null DbEntity, can't create id.");
232 }
233
234 this.readingIds = true;
235 this.nextDataRow = null;
236
237 while (wrappedIterator.hasNextRow()) {
238 Map next = wrappedIterator.nextObjectId(entity);
239
240 if (fetchedIds.add(next)) {
241 this.nextDataRow = next;
242 break;
243 }
244 }
245 }
246 } |
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