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34 package smallsql.database;
35
36 import java.io.File  ;
37 import java.io.RandomAccessFile ;
38 import java.sql.DriverManager ;
39 import java.sql.SQLException ;
40
41
42
43 final class IndexDescription {
44
45 static final int MAGIC_INDEX = 'S' << 24 | 'Q' << 16 | 'L' << 8 | 'I';
46 static final int INDEX_VERSION = 1;
47
48 private final String name;
49 final private int constraintType; final private Strings columns;
51 private int[] matrix;
52 final private Expressions expressions;
53 private Index index;
54 private RandomAccessFile raFile;
55
56
57
62 IndexDescription( String name, String tableName, int constraintType, Expressions expressions, Strings columns){
63 this.constraintType = constraintType;
64 this.expressions = expressions;
65 this.columns = columns;
66 this.name = createName(name, tableName);
67 }
68
69
70 private static String createName( String defaultName, String tableName ){
71 if(defaultName == null){
72 defaultName = tableName + "_" + Long.toHexString(System.currentTimeMillis()) + Integer.toHexString(new Object ().hashCode());
73 }
74 return defaultName;
75 }
76
77
78 final String getName(){
79 return name;
80 }
81
82
83 final boolean isPrimary(){
84 return constraintType == SQLTokenizer.PRIMARY;
85 }
86
87
88 final boolean isUnique(){
89 return constraintType == SQLTokenizer.PRIMARY || constraintType == SQLTokenizer.UNIQUE;
90 }
91
92
93 final Strings getColumns(){
94 return columns;
95 }
96
97
98
103 final int matchFactor(Strings strings){
104 if(strings.size() < columns.size())
105 return Integer.MAX_VALUE;
107 nextColumn:
108 for(int c=0; c<columns.size(); c++){
109 String colName = columns.get(c);
110 for(int s=0; s<strings.size(); s++){
111 if(colName.equalsIgnoreCase(strings.get(s)) )
112 continue nextColumn;
113 }
114 return Integer.MAX_VALUE; }
116 return strings.size() - columns.size();
117 }
118
119
120
126 final void init(Database database, TableView tableView){
127 int size = tableView.columns.size();
128 matrix = new int[size];
129 for(int i=0; i<matrix.length; i++){
130 matrix[i] = -1;
131 }
132
133 for(int i=0; i<columns.size(); i++){
134 matrix[tableView.findColumnIdx(columns.get(i))] = i;
135 }
136 }
137
138
139
142 final void create(Database database, TableView tableView) throws Exception {
143 init( database, tableView );
144 raFile = createFile( database );
145 }
146
147
148 static File getFile(Database database, String name) throws Exception {
149 return new File ( Utils.createIdxFileName( database, name ) );
150 }
151
152
153 private RandomAccessFile createFile(Database database) throws Exception {
154 File file = getFile( database, name );
155 boolean ok = file.createNewFile();
156 if(!ok) throw Utils.createSQLException("Index '" + name + "' already exists.");
157 RandomAccessFile randomFile = new RandomAccessFile ( file, "rw" );
158 writeMagic(randomFile);
159 return randomFile;
160 }
161
162
163 private void load(Database database) throws SQLException {
164 try{
165 File file = getFile( database, name );
166 if(!file.exists())
167 throw Utils.createSQLException("Index '" + name + "' does not exist");
168 raFile = new RandomAccessFile ( file, "rw" );
169 int magic = raFile.readInt();
170 int version = raFile.readInt();
171 if(magic != MAGIC_INDEX){
172 throw Utils.createSQLException("File '" + file.getName() + "' is not a valid Index store.");
173 }
174 if(version > INDEX_VERSION){
175 throw Utils.createSQLException("File version (" + version + ") of file '" + file.getName() + "' is to new for this runtume.");
176 }
177 }catch(Throwable e){
178 if(raFile != null)
179 try{
180 raFile.close();
181 }catch(Exception e2){
182 DriverManager.println(e2.toString());
183 }
184 throw Utils.createSQLException(e);
185 }
186 }
187
188
189 void drop(Database database) throws Exception {
190 close();
191 boolean ok = getFile( database, name).delete();
192 if(!ok) throw Utils.createSQLException("Table '" + name + "' can't drop.");
193 }
194
195
196 void close() throws Exception {
197 if(raFile != null){
198 raFile.close();
199 raFile = null;
200 }
201 }
202
203
204 private final void writeMagic(RandomAccessFile raFile) throws Exception {
205 raFile.writeInt(MAGIC_INDEX);
206 raFile.writeInt(INDEX_VERSION);
207 }
208
209
210
215 final void writeExpression( int columnIdx, Expression valueExpression) {
216 int idx = matrix[columnIdx];
217 if(idx >= 0) expressions.set(idx, valueExpression);
219 }
220
221
222
226 final void writeFinsh(SSConnection con) {
227 }
230
231
232
235 final void save(StoreImpl store) throws SQLException {
236 store.writeInt(constraintType);
237 store.writeInt(columns.size());
238 for(int c=0; c<columns.size(); c++){
239 store.writeString( columns.get(c) );
240 }
241 store.writeString(name);
242 }
243
244
245
248 final static IndexDescription load(Database database, TableView tableView, StoreImpl store) throws SQLException {
249 int constraintType = store.readInt();
250 int count = store.readInt();
251 Strings columns = new Strings();
252 Expressions expressions = new Expressions();
253 SQLParser sqlParser = new SQLParser();
254 for(int c=0; c<count; c++){
255 String column = store.readString();
256 columns.add( column );
257 expressions.add( sqlParser.parseExpression(column));
258 }
259 IndexDescription indexDesc = new IndexDescription( store.readString(), tableView.name, constraintType, expressions, columns);
260 indexDesc.init( database, tableView );
261 indexDesc.load(database);
262 return indexDesc;
263 }
264
265
266 }
267 |
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