| 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 | * Expression.java |
| 29 | * --------------- |
| 30 | * Author: Volker Berlin |
| 31 | * |
| 32 | */ |
| 33 | package smallsql.database; |
| 34 | |
| 35 | |
| 36 | abstract class Expression implements Cloneable{ |
| 37 | |
| 38 | static final Expression NULL = new ExpressionValue( null, SQLTokenizer.NULL ); |
| 39 | |
| 40 | final private int type; |
| 41 | private String name; // the name of the original column in the table |
| 42 | private String alias; |
| 43 | |
| 44 | /** |
| 45 | * A list of parameters. It is used for ExpressionFunction and ExpressionAritmethik. |
| 46 | * Do not modify this varaiable from extern directly because there are other references. |
| 47 | * Use the methods setParams() and setParamAt() |
| 48 | * @see #setParams |
| 49 | * @see setParamAt |
| 50 | */ |
| 51 | private Expression[] params; |
| 52 | |
| 53 | Expression(int type){ |
| 54 | this.type = type; |
| 55 | } |
| 56 | |
| 57 | protected Object clone() throws CloneNotSupportedException{ |
| 58 | return super.clone(); |
| 59 | } |
| 60 | |
| 61 | final String getName(){ |
| 62 | return name; |
| 63 | } |
| 64 | |
| 65 | final void setName(String name){ |
| 66 | this.alias = this.name = name; |
| 67 | } |
| 68 | |
| 69 | final String getAlias(){ |
| 70 | return alias; |
| 71 | } |
| 72 | |
| 73 | final void setAlias(String alias){ |
| 74 | this.alias = alias; |
| 75 | } |
| 76 | |
| 77 | void setParams( Expression[] params ){ |
| 78 | this.params = params; |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Replace the idx parameter. You need to use this method to modify the params |
| 83 | * array because there there can be other references to the params. |
| 84 | */ |
| 85 | void setParamAt( Expression param, int idx){ |
| 86 | params[idx] = param; |
| 87 | } |
| 88 | |
| 89 | final Expression[] getParams(){ return params; } |
| 90 | |
| 91 | /** |
| 92 | * Is used in GroupResult. |
| 93 | */ |
| 94 | public boolean equals(Object expr){ |
| 95 | if(!(expr instanceof Expression)) return false; |
| 96 | if( ((Expression)expr).type == type){ |
| 97 | |
| 98 | Expression[] p1 = ((Expression)expr).params; |
| 99 | Expression[] p2 = params; |
| 100 | if(p1 != null && p2 != null){ |
| 101 | if(p1 == null) return false; |
| 102 | for(int i=0; i<p1.length; i++){ |
| 103 | if(!p2[i].equals(p1[i])) return false; |
| 104 | } |
| 105 | } |
| 106 | String name1 = ((Expression)expr).name; |
| 107 | String name2 = name; |
| 108 | if(name1 == name2) return true; |
| 109 | if(name1 == null) return false; |
| 110 | if(name1.equalsIgnoreCase(name2)) return true; |
| 111 | } |
| 112 | return false; |
| 113 | } |
| 114 | |
| 115 | |
| 116 | abstract boolean isNull() throws Exception; |
| 117 | |
| 118 | abstract boolean getBoolean() throws Exception; |
| 119 | |
| 120 | abstract int getInt() throws Exception; |
| 121 | |
| 122 | abstract long getLong() throws Exception; |
| 123 | |
| 124 | abstract float getFloat() throws Exception; |
| 125 | |
| 126 | abstract double getDouble() throws Exception; |
| 127 | |
| 128 | abstract long getMoney() throws Exception; |
| 129 | |
| 130 | abstract MutableNumeric getNumeric() throws Exception; |
| 131 | |
| 132 | abstract Object getObject() throws Exception; |
| 133 | |
| 134 | final Object getApiObject() throws Exception{ |
| 135 | Object obj = getObject(); |
| 136 | if(obj instanceof Mutable){ |
| 137 | return ((Mutable)obj).getImmutableObject(); |
| 138 | } |
| 139 | return obj; |
| 140 | } |
| 141 | |
| 142 | abstract String getString() throws Exception; |
| 143 | |
| 144 | abstract byte[] getBytes() throws Exception; |
| 145 | |
| 146 | abstract int getDataType(); |
| 147 | |
| 148 | final int getType(){return type;} |
| 149 | |
| 150 | /*======================================================================= |
| 151 | |
| 152 | Methods for ResultSetMetaData |
| 153 | |
| 154 | =======================================================================*/ |
| 155 | |
| 156 | String getTableName(){ |
| 157 | return null; |
| 158 | } |
| 159 | |
| 160 | |
| 161 | int getPrecision(){ |
| 162 | return SSResultSetMetaData.getDataTypePrecision( getDataType(), -1 ); |
| 163 | } |
| 164 | |
| 165 | |
| 166 | |
| 167 | int getScale(){ |
| 168 | return getScale(getDataType()); |
| 169 | } |
| 170 | |
| 171 | |
| 172 | final static int getScale(int dataType){ |
| 173 | switch(dataType){ |
| 174 | case SQLTokenizer.MONEY: |
| 175 | case SQLTokenizer.SMALLMONEY: |
| 176 | return 4; |
| 177 | case SQLTokenizer.TIMESTAMP: |
| 178 | return 9; //nanos |
| 179 | case SQLTokenizer.NUMERIC: |
| 180 | case SQLTokenizer.DECIMAL: |
| 181 | return 38; |
| 182 | default: return 0; |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | |
| 187 | int getDisplaySize(){ |
| 188 | return SSResultSetMetaData.getDisplaySize(getDataType(), getPrecision(), getScale()); |
| 189 | } |
| 190 | |
| 191 | boolean isDefinitelyWritable(){ |
| 192 | return false; |
| 193 | } |
| 194 | |
| 195 | boolean isAutoIncrement(){ |
| 196 | return false; |
| 197 | } |
| 198 | |
| 199 | boolean isCaseSensitive(){ |
| 200 | return false; //TODO sollte wenn es von ExpressionName kommt durchgereicht werden |
| 201 | } |
| 202 | |
| 203 | boolean isNullable(){ |
| 204 | return true; //TODO könnte differenzierter sein |
| 205 | } |
| 206 | |
| 207 | |
| 208 | static final int VALUE = 1; |
| 209 | static final int NAME = 2; |
| 210 | static final int FUNCTION = 3; |
| 211 | static final int GROUP_BY = 11; |
| 212 | static final int COUNT = 12; |
| 213 | static final int SUM = 13; |
| 214 | static final int FIRST = 14; |
| 215 | static final int LAST = 15; |
| 216 | static final int MIN = 16; |
| 217 | static final int MAX = 17; |
| 218 | static final int GROUP_BEGIN= GROUP_BY; |
| 219 | |
| 220 | } |