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1
21 package com.db4o.inside.classindex;
22
23 import com.db4o.*;
24 import com.db4o.foundation.*;
25 import com.db4o.inside.btree.*;
26
27
30 public class BTreeClassIndexStrategy extends AbstractClassIndexStrategy {
31
32 private BTree _btreeIndex;
33
34 public BTreeClassIndexStrategy(YapClass yapClass) {
35 super(yapClass);
36 }
37
38 public BTree btree() {
39 return _btreeIndex;
40 }
41
42 public int entryCount(Transaction ta) {
43 return _btreeIndex != null
44 ? _btreeIndex.size(ta)
45 : 0;
46 }
47
48 public void initialize(YapStream stream) {
49 createBTreeIndex(stream, 0);
50 }
51
52 public void purge() {
53 }
54
55 public void read(YapStream stream, int indexID) {
56 readBTreeIndex(stream, indexID);
57 }
58
59 public int write(Transaction trans) {
60 if (_btreeIndex == null){
61 return 0;
62 }
63 _btreeIndex.write(trans);
64 return _btreeIndex.getID();
65 }
66
67 public void traverseAll(Transaction ta,Visitor4 command) {
68 if(_btreeIndex!=null) {
70 _btreeIndex.traverseKeys(ta,command);
71 }
72 }
73
74 private void createBTreeIndex(final YapStream stream, int btreeID){
75 if (stream.isClient()) {
76 return;
77 }
78 _btreeIndex = ((YapFile)stream).createBTreeClassIndex(btreeID);
79 _btreeIndex.setRemoveListener(new Visitor4() {
80 public void visit(Object  obj) {
81 int id = ((Integer )obj).intValue();
82 YapObject yo = stream.getYapObject(id);
83 if (yo != null) {
84 stream.removeReference(yo);
85 }
86 }
87 });
88 }
89
90 private void readBTreeIndex(YapStream stream, int indexId) {
91 if(! stream.isClient() && _btreeIndex == null){
92 createBTreeIndex(stream, indexId);
93 }
94 }
95
96 protected void internalAdd(Transaction trans, int id) {
97 _btreeIndex.add(trans, new Integer (id));
98 }
99
100 protected void internalRemove(Transaction ta, int id) {
101 _btreeIndex.remove(ta, new Integer (id));
102 }
103
104 public void dontDelete(Transaction transaction, int id) {
105 }
106
107 public void defragReference(YapClass yapClass, ReaderPair readers,int classIndexID) {
108 int newID = -classIndexID;
109 readers.writeInt(newID);
110 }
111
112 public int id() {
113 return _btreeIndex.getID();
114 }
115
116 public Iterator4 allSlotIDs(Transaction trans) {
117 return _btreeIndex.allNodeIds(trans);
118 }
119
120 public void defragIndex(ReaderPair readers) {
121 _btreeIndex.defragIndex(readers);
122 }
123
124 public static BTree btree(YapClass clazz) {
125 ClassIndexStrategy index = clazz.index();
126 if(! (index instanceof BTreeClassIndexStrategy)){
127 throw new IllegalStateException ();
128 }
129 return ((BTreeClassIndexStrategy)index).btree();
130 }
131
132 public static Iterator4 iterate(YapClass clazz, Transaction trans) {
133 return btree(clazz).asRange(trans).keys();
134 }
135
136
137
138 }
139 |
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