| 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 | * TableView.java |
| 29 | * --------------- |
| 30 | * Author: Volker Berlin |
| 31 | * |
| 32 | * Created on 05.06.2004 |
| 33 | */ |
| 34 | package smallsql.database; |
| 35 | |
| 36 | import java.io.*; |
| 37 | import java.sql.*; |
| 38 | |
| 39 | |
| 40 | /** |
| 41 | * @author Volker Berlin |
| 42 | */ |
| 43 | abstract class TableView { |
| 44 | |
| 45 | static final int MAGIC_TABLE = 'S' << 24 | 'Q' << 16 | 'L' << 8 | 'T'; |
| 46 | static final int MAGIC_VIEW = 'S' << 24 | 'Q' << 16 | 'L' << 8 | 'V'; |
| 47 | static final int TABLE_VIEW_VERSION = 2; |
| 48 | static final int TABLE_VIEW_OLD_VERSION = 1; |
| 49 | |
| 50 | final String name; |
| 51 | final Columns columns; |
| 52 | |
| 53 | /** |
| 54 | * Mark the last change on the structur of the Table or View. |
| 55 | * If this value change then PreparedStatements need to recompile. |
| 56 | */ |
| 57 | private long timestamp = System.currentTimeMillis(); |
| 58 | |
| 59 | static final int LOCK_NONE = 0; // read on READ_COMMITED and READ_UNCOMMITED |
| 60 | static final int LOCK_INSERT = 1; // verhindert nur LOCK_TAB |
| 61 | static final int LOCK_READ = 2; // Tritt beim Lesen auf und verhindert ein Schreiben der Daten, es kann mehr als ein LOCK_READ pro page auftreten |
| 62 | static final int LOCK_WRITE = 3; // Tritt beim Schreiben auf und verhindert jeden weiteren Zugriff, es ist nur ein LOCK_WRITE pro page möglich |
| 63 | static final int LOCK_TAB = 4; // Sperre der gesamten Tabelle |
| 64 | |
| 65 | |
| 66 | TableView(String name, Columns columns){ |
| 67 | this.name = name; |
| 68 | this.columns = columns; |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Load a Table or View object. |
| 73 | */ |
| 74 | static TableView load(SSConnection con, Database database, String name) throws SQLException{ |
| 75 | RandomAccessFile raFile = null; |
| 76 | try{ |
| 77 | String fileName = Utils.createTableViewFileName( database, name ); |
| 78 | File file = new File( fileName ); |
| 79 | if(!file.exists()) |
| 80 | throw Utils.createSQLException("Table or View '" + name + "' does not exist"); |
| 81 | raFile = new RandomAccessFile( file, "rw" ); |
| 82 | int magic = raFile.readInt(); |
| 83 | int version = raFile.readInt(); |
| 84 | switch(magic){ |
| 85 | case MAGIC_TABLE: |
| 86 | case MAGIC_VIEW: |
| 87 | break; |
| 88 | default: |
| 89 | throw Utils.createSQLException("File '" + fileName + "' is not a valid Table or View store."); |
| 90 | } |
| 91 | if(version > TABLE_VIEW_VERSION) |
| 92 | throw Utils.createSQLException("File version (" + version + ") of file '" + fileName + "' is to new for this runtume."); |
| 93 | if(version < TABLE_VIEW_OLD_VERSION) |
| 94 | throw Utils.createSQLException("File version (" + version + ") of file '" + fileName + "' is to old for this runtume."); |
| 95 | if(magic == MAGIC_TABLE) |
| 96 | return new Table( con, name, raFile, raFile.getFilePointer(), version); |
| 97 | return new View ( con, name, raFile, raFile.getFilePointer()); |
| 98 | }catch(Throwable e){ |
| 99 | if(raFile != null) |
| 100 | try{ |
| 101 | raFile.close(); |
| 102 | }catch(Exception e2){ |
| 103 | DriverManager.println(e2.toString()); |
| 104 | } |
| 105 | throw Utils.createSQLException(e); |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | |
| 110 | File getFile(Database database, String name) throws Exception{ |
| 111 | return new File( Utils.createTableViewFileName( database, name ) ); |
| 112 | } |
| 113 | |
| 114 | |
| 115 | RandomAccessFile createFile(Database database) throws Exception{ |
| 116 | File file = getFile( database, name ); |
| 117 | boolean ok = file.createNewFile(); |
| 118 | if(!ok) throw Utils.createSQLException("Table or View '" + name + "' allready exists."); |
| 119 | RandomAccessFile raFile = new RandomAccessFile( file, "rw" ); |
| 120 | writeMagic(raFile); |
| 121 | return raFile; |
| 122 | } |
| 123 | |
| 124 | abstract void writeMagic(RandomAccessFile raFile) throws Exception; |
| 125 | |
| 126 | |
| 127 | String getName(){ |
| 128 | return name; |
| 129 | } |
| 130 | |
| 131 | |
| 132 | long getTimestamp(){ |
| 133 | return timestamp; |
| 134 | } |
| 135 | |
| 136 | |
| 137 | /** |
| 138 | * Returns the index of a column name. The first column has the index 0. |
| 139 | */ |
| 140 | final int findColumnIdx(String name){ |
| 141 | // FIXME auf tree suche umstellen aus Performance Günden |
| 142 | for(int i=0; i<columns.size(); i++){ |
| 143 | if( columns.get(i).getName().equalsIgnoreCase(name) ) return i; |
| 144 | } |
| 145 | return -1; |
| 146 | } |
| 147 | |
| 148 | |
| 149 | /** |
| 150 | * Returns the Column of a column name. |
| 151 | */ |
| 152 | final Column findColumn(String name){ |
| 153 | for(int i=0; i<columns.size(); i++){ |
| 154 | Column column = columns.get(i); |
| 155 | if( column.getName().equalsIgnoreCase(name) ) return column; |
| 156 | } |
| 157 | return null; |
| 158 | } |
| 159 | |
| 160 | |
| 161 | |
| 162 | /** |
| 163 | * Close it and free all resources. |
| 164 | */ |
| 165 | void close() throws Exception{ |
| 166 | |
| 167 | } |
| 168 | |
| 169 | } |
| 170 | |
| 171 | |