| 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 | * .java |
| 29 | * --------------- |
| 30 | * Author: Volker Berlin |
| 31 | * |
| 32 | * Created on 17.04.2004 |
| 33 | */ |
| 34 | package smallsql.database; |
| 35 | |
| 36 | /** |
| 37 | * This class is used for SELECT command without FROM clause. |
| 38 | * |
| 39 | * @author Volker Berlin |
| 40 | */ |
| 41 | final class NoFromResult extends RowSource { |
| 42 | |
| 43 | private int rowPos; // 0-before; 1-on row; 2-after last |
| 44 | |
| 45 | |
| 46 | final boolean isScrollable(){ |
| 47 | return true; |
| 48 | } |
| 49 | |
| 50 | |
| 51 | final void beforeFirst(){ |
| 52 | rowPos = 0; |
| 53 | } |
| 54 | |
| 55 | final boolean isBeforeFirst(){ |
| 56 | return rowPos <= 0; |
| 57 | } |
| 58 | |
| 59 | final boolean isFirst(){ |
| 60 | return rowPos == 1; |
| 61 | } |
| 62 | |
| 63 | final boolean first(){ |
| 64 | rowPos = 1; |
| 65 | return true; |
| 66 | } |
| 67 | |
| 68 | final boolean previous(){ |
| 69 | rowPos--; |
| 70 | return rowPos == 1; |
| 71 | } |
| 72 | |
| 73 | |
| 74 | final boolean next(){ |
| 75 | rowPos++; |
| 76 | return rowPos == 1; |
| 77 | } |
| 78 | |
| 79 | final boolean last(){ |
| 80 | rowPos = 1; |
| 81 | return true; |
| 82 | } |
| 83 | |
| 84 | final boolean isLast(){ |
| 85 | return rowPos == 1; |
| 86 | } |
| 87 | |
| 88 | final boolean isAfterLast(){ |
| 89 | return rowPos > 1; |
| 90 | } |
| 91 | |
| 92 | final void afterLast(){ |
| 93 | rowPos = 2; |
| 94 | } |
| 95 | |
| 96 | final boolean absolute(int row){ |
| 97 | rowPos = (row > 0) ? |
| 98 | Math.min( row, 1 ) : |
| 99 | Math.min( row +1, -1 ); |
| 100 | return rowPos == 1; |
| 101 | } |
| 102 | |
| 103 | final boolean relative(int rows){ |
| 104 | if(rows == 0) return rowPos == 1; |
| 105 | rowPos = Math.min( Math.max( rowPos + rows, -1), 1); |
| 106 | return rowPos == 1; |
| 107 | } |
| 108 | |
| 109 | final int getRow(){ |
| 110 | return rowPos == 1 ? 1 : 0; |
| 111 | } |
| 112 | |
| 113 | final long getRowPosition() { |
| 114 | return rowPos; |
| 115 | } |
| 116 | |
| 117 | |
| 118 | final void setRowPosition(long rowPosition){ |
| 119 | rowPos = (int)rowPosition; |
| 120 | } |
| 121 | |
| 122 | |
| 123 | final boolean rowInserted(){ |
| 124 | return false; |
| 125 | } |
| 126 | |
| 127 | |
| 128 | final boolean rowDeleted(){ |
| 129 | return false; |
| 130 | } |
| 131 | |
| 132 | |
| 133 | final void nullRow() { |
| 134 | throw new Error(); |
| 135 | } |
| 136 | |
| 137 | |
| 138 | final void noRow() { |
| 139 | throw new Error(); |
| 140 | } |
| 141 | |
| 142 | |
| 143 | final void execute() throws Exception{ |
| 144 | } |
| 145 | } |