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21 package com.db4o.inside.classindex;
22
23 import com.db4o.*;
24 import com.db4o.foundation.*;
25
26
29 public class OldClassIndexStrategy extends AbstractClassIndexStrategy implements TransactionParticipant {
30
31 private ClassIndex _index;
32
33 private final Hashtable4 _perTransaction = new Hashtable4();
34
35 public OldClassIndexStrategy(YapClass yapClass) {
36 super(yapClass);
37 }
38
39 public void read(YapStream stream, int indexID) {
40 _index = createClassIndex(stream);
41 if (indexID > 0) {
42 _index.setID(indexID);
43 }
44 _index.setStateDeactivated();
45 }
46
47 private ClassIndex getActiveIndex(Transaction transaction) {
48 if (null != _index) {
49 _index.ensureActive(transaction);
50 }
51 return _index;
52 }
53
54 public int entryCount(Transaction transaction) {
55 if (_index != null) {
56 return _index.entryCount(transaction);
57 }
58 return 0;
59 }
60
61 public void initialize(YapStream stream) {
62 _index = createClassIndex(stream);
63 }
64
65 public void purge() {
66 if (_index != null) {
67 if (!_index.isDirty()) {
68 _index.clear();
69 _index.setStateDeactivated();
70 }
71 }
72 }
73
74 public int write(Transaction transaction) {
75 if(_index == null){
76 return 0;
77 }
78 _index.write(transaction);
79 return _index.getID();
80 }
81
82 private void flushContext(final Transaction transaction) {
83 TransactionState context = getState(transaction);
84
85 final ClassIndex index = getActiveIndex(transaction);
86 context.traverseAdded(new Visitor4() {
87 public void visit(Object  a_object) {
88 index.add(idFromValue(a_object));
89 }
90 });
91
92 context.traverseRemoved(new Visitor4() {
93 public void visit(Object a_object) {
94 int id = idFromValue(a_object);
95 final YapStream stream = transaction.stream();
96 YapObject yo = stream.getYapObject(id);
97 if (yo != null) {
98 stream.removeReference(yo);
99 }
100 index.remove(id);
101 }
102 });
103 }
104
105 private void writeIndex(Transaction transaction) {
106 _index.setStateDirty();
107 _index.write(transaction);
108 }
109
110 final static class TransactionState {
111
112 private Tree i_addToClassIndex;
113
114 private Tree i_removeFromClassIndex;
115
116 public void add(int id) {
117 i_removeFromClassIndex = Tree.removeLike(i_removeFromClassIndex, new TreeInt(id));
118 i_addToClassIndex = Tree.add(i_addToClassIndex, new TreeInt(id));
119 }
120
121 public void remove(int id) {
122 i_addToClassIndex = Tree.removeLike(i_addToClassIndex, new TreeInt(id));
123 i_removeFromClassIndex = Tree.add(i_removeFromClassIndex, new TreeInt(id));
124 }
125
126 public void dontDelete(int id) {
127 i_removeFromClassIndex = Tree.removeLike(i_removeFromClassIndex, new TreeInt(id));
128 }
129
130 void traverse(Tree node, Visitor4 visitor) {
131 if (node != null) {
132 node.traverse(visitor);
133 }
134 }
135
136 public void traverseAdded(Visitor4 visitor4) {
137 traverse(i_addToClassIndex, visitor4);
138 }
139
140 public void traverseRemoved(Visitor4 visitor4) {
141 traverse(i_removeFromClassIndex, visitor4);
142 }
143 }
144
145 protected void internalAdd(Transaction transaction, int id) {
146 getState(transaction).add(id);
147 }
148
149 private TransactionState getState(Transaction transaction) {
150 synchronized (_perTransaction) {
151 TransactionState context = (TransactionState)_perTransaction.get(transaction);
152 if (null == context) {
153 context = new TransactionState();
154 _perTransaction.put(transaction, context);
155 transaction.enlist(this);
156 }
157 return context;
158 }
159 }
160
161 private Tree getAll(Transaction transaction) {
162 ClassIndex ci = getActiveIndex(transaction);
163 if (ci == null) {
164 return null;
165 }
166
167 final Tree.ByRef tree = new Tree.ByRef(Tree.deepClone(ci.getRoot(), null));
168 TransactionState context = getState(transaction);
169 context.traverseAdded(new Visitor4() {
170 public void visit(Object obj) {
171 tree.value = Tree.add(tree.value, new TreeInt(idFromValue(obj)));
172 }
173 });
174 context.traverseRemoved(new Visitor4() {
175 public void visit(Object obj) {
176 tree.value = Tree.removeLike(tree.value, (TreeInt) obj);
177 }
178 });
179 return tree.value;
180 }
181
182 protected void internalRemove(Transaction transaction, int id) {
183 getState(transaction).remove(id);
184 }
185
186 public void traverseAll(Transaction transaction, final Visitor4 command) {
187 Tree tree = getAll(transaction);
188 if (tree != null) {
189 tree.traverse(new Visitor4() {
190 public void visit(Object obj) {
191 command.visit(new Integer (idFromValue(obj)));
192 }
193 });
194 }
195 }
196
197 public int idFromValue(Object value) {
198 return ((TreeInt) value)._key;
199 }
200
201 private ClassIndex createClassIndex(YapStream stream) {
202 if (stream.isClient()) {
203 return new ClassIndexClient(_yapClass);
204 }
205 return new ClassIndex(_yapClass);
206 }
207
208 public void dontDelete(Transaction transaction, int id) {
209 getState(transaction).dontDelete(id);
210 }
211
212 public void commit(Transaction trans) {
213 if (null != _index) {
214 flushContext(trans);
215 writeIndex(trans);
216 }
217 }
218
219 public void dispose(Transaction transaction) {
220 synchronized (_perTransaction) {
221 _perTransaction.remove(transaction);
222 }
223 }
224
225 public void rollback(Transaction transaction) {
226 }
228
229 public void defragReference(YapClass yapClass, ReaderPair readers,int classIndexID) {
230 }
231
232 public int id() {
233 return _index.getID();
234 }
235
236
237 public Iterator4 allSlotIDs(Transaction trans){
238 throw new NotImplementedException();
239 }
240
241 public void defragIndex(ReaderPair readers) {
242 }
243 }
244 |
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