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1
19
20 package org.apache.cayenne.access.util;
21
22 import java.util.ArrayList  ;
23 import java.util.HashMap ;
24 import java.util.HashSet ;
25 import java.util.Iterator ;
26 import java.util.List ;
27 import java.util.Map ;
28 import java.util.Set ;
29
30 import org.apache.cayenne.CayenneException;
31 import org.apache.cayenne.access.ResultIterator;
32 import org.apache.cayenne.map.DbAttribute;
33 import org.apache.cayenne.map.DbEntity;
34
35
46 public class DistinctResultIterator implements ResultIterator {
47
48 protected ResultIterator wrappedIterator;
49 protected Set fetchedIds;
50 protected Map nextDataRow;
51 protected DbEntity defaultEntity;
52 protected boolean compareFullRows;
53
54 protected boolean readingIds;
55
56
62 public DistinctResultIterator(ResultIterator wrappedIterator, DbEntity defaultEntity,
63 boolean compareFullRows) throws CayenneException {
64 if (wrappedIterator == null) {
65 throw new CayenneException("Null wrapped iterator.");
66 }
67
68 if (defaultEntity == null) {
69 throw new CayenneException("Null defaultEntity.");
70 }
71
72 this.wrappedIterator = wrappedIterator;
73 this.defaultEntity = defaultEntity;
74 this.fetchedIds = new HashSet ();
75 this.compareFullRows = compareFullRows;
76
77 checkNextRow();
78 }
79
80
83 public void close() throws CayenneException {
84 wrappedIterator.close();
85 }
86
87
90 public List dataRows(boolean close) throws CayenneException {
91 List list = new ArrayList ();
92
93 try {
94 while (this.hasNextRow()) {
95 list.add(this.nextDataRow());
96 }
97 return list;
98 }
99 finally {
100 if (close) {
101 this.close();
102 }
103 }
104 }
105
106 public int getDataRowWidth() {
107 return wrappedIterator.getDataRowWidth();
108 }
109
110 public boolean hasNextRow() throws CayenneException {
111 return nextDataRow != null;
112 }
113
114 public Map nextDataRow() throws CayenneException {
115 if (!hasNextRow()) {
116 throw new CayenneException(
117 "An attempt to read uninitialized row or past the end of the iterator.");
118 }
119
120 Map row = nextDataRow;
121 checkNextRow();
122 return row;
123 }
124
125
129 public Map nextObjectId(DbEntity entity) throws CayenneException {
130 if (!hasNextRow()) {
131 throw new CayenneException(
132 "An attempt to read uninitialized row or past the end of the iterator.");
133 }
134
135 Map row = nextDataRow;
136
137 if (!readingIds) {
139 Iterator it = row.entrySet().iterator();
140 while (it.hasNext()) {
141 Map.Entry entry = (Map.Entry ) it.next();
142 String name = (String ) entry.getKey();
143 DbAttribute attribute = (DbAttribute) entity.getAttribute(name);
144 if (attribute == null || !attribute.isPrimaryKey()) {
145 it.remove();
146 }
147 }
148 }
149
150 checkNextId(entity);
151 return row;
152 }
153
154 public void skipDataRow() throws CayenneException {
155 if (!hasNextRow()) {
156 throw new CayenneException(
157 "An attempt to read uninitialized row or past the end of the iterator.");
158 }
159
160 if (readingIds) {
161 checkNextId(defaultEntity);
162 }
163 else {
164 checkNextRow();
165 }
166 }
167
168 void checkNextRow() throws CayenneException {
169 if (readingIds) {
170 throw new CayenneException(
171 "Can't go back from reading ObjectIds to reading rows.");
172 }
173
174 if (this.compareFullRows) {
175 checkNextUniqueRow();
176 }
177 else {
178 checkNextRowWithUniqueId();
179 }
180 }
181
182 void checkNextUniqueRow() throws CayenneException {
183
184 nextDataRow = null;
185 while (wrappedIterator.hasNextRow()) {
186 Map next = wrappedIterator.nextDataRow();
187
188 if (fetchedIds.add(next)) {
189 this.nextDataRow = next;
190 break;
191 }
192 }
193 }
194
195 void checkNextRowWithUniqueId() throws CayenneException {
196
197 nextDataRow = null;
198 while (wrappedIterator.hasNextRow()) {
199 Map next = wrappedIterator.nextDataRow();
200
201
205 Map id = new HashMap ();
206 Iterator it = defaultEntity.getPrimaryKey().iterator();
207 while (it.hasNext()) {
208 DbAttribute pk = (DbAttribute) it.next();
209 id.put(pk.getName(), next.get(pk.getName()));
210 }
211
212 if (fetchedIds.add(id)) {
213 this.nextDataRow = next;
214 break;
215 }
216 }
217 }
218
219 void checkNextId(DbEntity entity) throws CayenneException {
220 if (entity == null) {
221 throw new CayenneException("Null DbEntity, can't create id.");
222 }
223
224 this.readingIds = true;
225 this.nextDataRow = null;
226
227 while (wrappedIterator.hasNextRow()) {
228 Map next = wrappedIterator.nextObjectId(entity);
229
230 if (fetchedIds.add(next)) {
232 this.nextDataRow = next;
233 break;
234 }
235 }
236 }
237 }
238 |
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