TableResult


1   /* =============================================================
2    * SmallSQL : a free Java DBMS library for the Java(tm) platform
3    * =============================================================
4    *
5    * (C) Copyright 2004-2006, by Volker Berlin.
6    *
7    * Project Info:  http://www.smallsql.de/
8    *
9    * This library is free software; you can redistribute it and/or modify it 
10   * under the terms of the GNU Lesser General Public License as published by 
11   * the Free Software Foundation; either version 2.1 of the License, or 
12   * (at your option) any later version.
13   *
14   * This library is distributed in the hope that it will be useful, but 
15   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
16   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
17   * License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this library; if not, write to the Free Software
21   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
22   * USA.  
23   *
24   * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
25   * in the United States and other countries.]
26   *
27   * ---------------
28   * TableResult.java
29   * ---------------
30   * Author: Volker Berlin
31   * 
32   */
33  package smallsql.database;
34  
35  import java.sql.*;
36  import java.util.List  ;
37  
38  
39  final class TableResult extends TableViewResult{
40  
41      final private Table table;
42      /** A List of rows that was inserted. The rows can be uncommited in memory or commited on harddisk.
43       *  The WHERE condition does not need to be valid.
44       */ 
45      private List   insertStorePages;
46      /**
47       * The filePos of the first own insert with insertRow(). On this rows the WHERE condition is not verify.
48       */
49      private long firstOwnInsert; 
50      /**
51       * The max fileOffset at open the ResultSet. Rows that are commited later are not not counted.
52       */
53      private long maxFileOffset;
54      
55      TableResult(Table table){
56          this.table = table;
57      }
58      
59      
60      /**
61       * Is used for compile() of different Commands
62       * 
63       * @param con
64       * @return true if now init; false if already init
65       * @throws Exception
66       */
67      final boolean init( SSConnection con ) throws Exception  {
68          if(super.init(con)){
69              Columns columns = table.columns;
70              offsets     = new int[columns.size()];
71              dataTypes   = new int[columns.size()];
72              for(int i=0; i<columns.size(); i++){
73                  dataTypes[i] = columns.get(i).getDataType();
74              }
75              return true;
76          }
77          return false;
78      }
79  
80  
81      final void execute() throws Exception  {
82          insertStorePages = table.getInserts(con);
83          firstOwnInsert = 0x4000000000000000L | insertStorePages.size();
84          maxFileOffset = table.raFile.length();
85          beforeFirst();
86      }
87  
88  /*==============================================================================
89  
90      Methods for base class TableViewResult
91  
92  ==============================================================================*/
93  
94      final TableView getTableView(){
95          return table;
96      }
97      
98  
99      
100     final void deleteRow() throws SQLException{
101         store.deleteRow(con); 
102         store = new StoreNull(store.getNextPagePos());
103     }
104     
105 
106     final void updateRow(Expression[] updateValues) throws Exception  {
107         Columns tableColumns = table.columns;
108         int count = tableColumns.size();
109             
110             
111         StoreImpl newStore = table.getStoreTemp(con);
112         for(int i=0; i<count; i++){
113             Expression src = updateValues[i];
114             if(src != null){                
115                 newStore.writeExpression( src, tableColumns.get(i) );
116             }else{
117                 copyValueInto( i, newStore );
118             }
119         }
120         ((StoreImpl)this.store).updateFinsh(con, newStore);
121     }
122     
123 
124     final void insertRow(Expression[] updateValues) throws Exception  {
125         Columns tableColumns = table.columns;
126         int count = tableColumns.size();
127         
128         // save the new values if there are new value for this table
129         StoreImpl store = table.getStoreInsert(con);
130         for(int i=0; i<count; i++){
131             Column tableColumn = tableColumns.get(i);
132             Expression src = updateValues[i];
133             if(src == null) src = tableColumn.getDefaultValue(con);
134             store.writeExpression( src, tableColumn );
135                         
136         }
137         store.writeFinsh( con );
138         insertStorePages.add(store.getLink());
139     }
140 
141 
142 /*==============================================================================
143 
144     Methods for Interface RowSource
145 
146 ==============================================================================*/
147     private Store store = Store.NOROW;
148     
149     /** The row position in the file of the table.  */  
150     private long filePos; 
151     private int[] offsets;
152     private int[] dataTypes;
153     private int row;
154 
155     
156     /**
157      * Move to the row in the filePos. A value of -1 for filePos is invalid at this call point.
158      */
159     final private boolean moveToRow() throws Exception  {
160         if(filePos >= 0x4000000000000000L){
161             store = ((StorePageLink)insertStorePages.get( (int)(filePos & 0x3FFFFFFFFFFFFFFFL) )).getStore( table, con, lock);
162         }else{
163             store = (filePos < maxFileOffset) ? table.getStore( con, filePos, lock ) : null;
164             if(store == null){
165                 if(insertStorePages.size() > 0){            
166                     filePos = 0x4000000000000000L;
167                     store = ((StorePageLink)insertStorePages.get( (int)(filePos & 0x3FFFFFFFFFFFFFFFL) )).getStore( table, con, lock);
168                 }
169             }
170         }
171         if(store != null){
172             if(!store.isValidPage()){
173                 return false;
174             }
175             store.scanObjectOffsets( offsets, dataTypes );
176             return true;
177         }else{
178             filePos = -1;
179             noRow();
180             return false;
181         }
182     }
183     
184     
185     /**
186      * Move to the next valid row. A valid row is a normal row or an pointer to an updated row value.
187      * A invalid row is a deleted row or an updated value that is reference by an update pointer. 
188      */
189     final private boolean moveToValidRow() throws Exception  {
190         while(filePos >= 0){
191             if(moveToRow())
192                 return true;
193             setNextFilePos();
194         }
195         row = 0;
196         return false;
197     }
198     
199 
200     final void beforeFirst(){
201         filePos = 0;
202         store = Store.NOROW;
203         row = 0;
204     }
205     
206 
207     final boolean first() throws Exception  {
208         filePos = table.getFirstPage();
209         row = 1;
210         return moveToValidRow();
211     }
212     
213     
214     /**
215      * A negative filePos means no more rows.<p>
216      * A value larger 0x4000000000000000L means a row that was inserted in this ResultSet.<p>
217      * A value of 0 means beforeFirst.<p>
218      * All other values are read position in the file.<p>
219      *
220      */
221     final private void setNextFilePos(){
222         if(filePos < 0) return; // end of rows
223         if(store == Store.NOROW)
224              filePos = table.getFirstPage(); // can point at the end of file
225         else
226         if(filePos >= 0x4000000000000000L){
227             filePos++;
228             if((filePos & 0x3FFFFFFFFFFFFFFFL) >= insertStorePages.size()){
229                 filePos = -1;
230                 noRow();
231             }
232         }else
233             filePos = store.getNextPagePos();
234     }
235     
236     final boolean next() throws Exception  {
237         if(filePos < 0) return false;
238         setNextFilePos();
239         row++;
240         return moveToValidRow();
241     }
242     
243     
244     final void afterLast(){
245         filePos = -1;
246         noRow();
247     }
248     
249     
250     final int getRow(){
251         return row;
252     }
253     
254     
255     /**
256      * Get the position of the row in the file. This is equals to the rowOffset.
257      */
258     final long getRowPosition(){
259         return filePos;
260     }
261     
262     
263     final void setRowPosition(long rowPosition) throws Exception  {
264         filePos = rowPosition;
265         if(filePos < 0 || !moveToRow()){
266             store = new StoreNull(store.getNextPagePos());
267         }
268     }
269     
270     
271     final boolean rowInserted(){
272         return filePos >= firstOwnInsert;
273     }
274     
275     
276     final boolean rowDeleted(){
277         // A StoreNull is created on setRowPosition on a deleted row
278         return store instanceof StoreNull && store != Store.NULL;
279     }
280     
281     
282     final void nullRow(){
283         row = 0;
284         store = Store.NULL;
285     }
286     
287 
288     final void noRow(){
289         row = 0;
290         store = Store.NOROW;
291     }
292     
293 
294 /*=======================================================================
295  
296     Methods for Data Access
297  
298 =======================================================================*/
299 
300     final boolean isNull( int colIdx ) throws Exception  {
301         return store.isNull( offsets[colIdx] );
302     }
303 
304     final boolean getBoolean( int colIdx ) throws Exception  {
305         return store.getBoolean( offsets[colIdx], dataTypes[colIdx] );
306     }
307 
308     final int getInt( int colIdx ) throws Exception  {
309         return store.getInt( offsets[colIdx], dataTypes[colIdx] );
310     }
311 
312     final long getLong( int colIdx ) throws Exception  {
313         return store.getLong( offsets[colIdx], dataTypes[colIdx] );
314     }
315 
316     final float getFloat( int colIdx ) throws Exception  {
317         return store.getFloat( offsets[colIdx], dataTypes[colIdx] );
318     }
319 
320     final double getDouble( int colIdx ) throws Exception  {
321         return store.getDouble( offsets[colIdx], dataTypes[colIdx] );
322     }
323 
324     final long getMoney( int colIdx ) throws Exception  {
325         return store.getMoney( offsets[colIdx], dataTypes[colIdx] );
326     }
327 
328     final MutableNumeric getNumeric( int colIdx ) throws Exception  {
329         return store.getNumeric( offsets[colIdx], dataTypes[colIdx] );
330     }
331 
332     final Object   getObject( int colIdx ) throws Exception  {
333         return store.getObject( offsets[colIdx], dataTypes[colIdx] );
334     }
335 
336     final String   getString( int colIdx ) throws Exception  {
337         return store.getString( offsets[colIdx], dataTypes[colIdx] );
338     }
339 
340     final byte[] getBytes( int colIdx ) throws Exception  {
341         return store.getBytes( offsets[colIdx], dataTypes[colIdx] );
342     }
343 
344     final int getDataType( int colIdx ){
345         return dataTypes[colIdx];
346     }
347     
348     final private void copyValueInto( int colIdx, StoreImpl dst){
349         int offset = offsets[colIdx++];
350         int length = (colIdx < offsets.length ? offsets[colIdx] : store.getUsedSize()) - offset;
351         dst.copyValueFrom( (StoreImpl)store, offset, length);
352     }
353 
354     
355 }
356
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