001 /*
002 // $Id: //open/mondrian/src/main/mondrian/olap/Literal.java#23 $
003 // This software is subject to the terms of the Common Public License
004 // Agreement, available at the following URL:
005 // http://www.opensource.org/licenses/cpl.html.
006 // Copyright (C) 1998-2002 Kana Software, Inc.
007 // Copyright (C) 2001-2008 Julian Hyde and others
008 // All Rights Reserved.
009 // You must accept the terms of that agreement to use this software.
010 //
011 // jhyde, 21 January, 1999
012 */
013
014 package mondrian.olap;
015 import mondrian.olap.type.*;
016 import mondrian.calc.*;
017 import mondrian.calc.impl.ConstantCalc;
018 import mondrian.mdx.MdxVisitor;
019
020 import java.io.PrintWriter;
021
022 /**
023 * Represents a constant value, such as a string or number, in a parse tree.
024 *
025 * <p>Symbols, such as the <code>ASC</code> keyword in
026 * <code>Order([Store].Members, [Measures].[Unit Sales], ASC)</code>, are
027 * also represented as Literals.
028 *
029 * @version $Id: //open/mondrian/src/main/mondrian/olap/Literal.java#23 $
030 * @author jhyde
031 */
032 public class Literal extends ExpBase {
033
034 // Data members.
035
036 public final int category;
037 private final Object o;
038
039
040 // Constants for commonly used literals.
041
042 public static final Literal nullValue = new Literal(Category.Null, null);
043
044 public static final Literal emptyString = new Literal("", false);
045
046 public static final Literal zero = new Literal(0);
047
048 public static final Literal one = new Literal(1);
049
050 public static final Literal negativeOne = new Literal(-1);
051
052 public static final Literal doubleZero = new Literal(0.0);
053
054 public static final Literal doubleOne = new Literal(1.0);
055
056 public static final Literal doubleNegativeOne = new Literal(-1.0);
057
058 /**
059 * Private constructor.
060 *
061 * <p>Use the creation methods {@link #createString(String)} etc.
062 */
063 private Literal(int type, Object o) {
064 this.category = type;
065 this.o = o;
066 }
067
068 /**
069 * Creates a string literal.
070 * @see #createSymbol
071 */
072 public static Literal createString(String s) {
073 return (s.equals(""))
074 ? emptyString
075 : new Literal(s, false);
076 }
077
078 /**
079 * Creates a symbol.
080 * @see #createString
081 */
082 public static Literal createSymbol(String s) {
083 return new Literal(s, true);
084 }
085
086 /**
087 * Creates a numeric literal.
088 */
089 public static Literal create(Double d) {
090 double dv = d.doubleValue();
091 if (dv == 0.0) {
092 return doubleZero;
093 } else if (dv == 1.0) {
094 return doubleOne;
095 } else if (dv == -1.0) {
096 return doubleNegativeOne;
097 } else {
098 return new Literal(d);
099 }
100 }
101
102 /**
103 * Creates an integer literal.
104 */
105 public static Literal create(Integer i) {
106 switch (i) {
107 case -1:
108 return negativeOne;
109 case 0:
110 return zero;
111 case 1:
112 return one;
113 default:
114 return new Literal(i);
115 }
116 }
117
118 private Literal(String s, boolean isSymbol) {
119 this.o = s;
120 this.category = isSymbol ? Category.Symbol : Category.String;
121 }
122
123 private Literal(Double d) {
124 this.o = d;
125 this.category = Category.Numeric;
126 }
127 private Literal(Integer i) {
128 this.o = i;
129 this.category = Category.Numeric;
130 }
131
132 public Literal clone() {
133 return this;
134 }
135
136 public void unparse(PrintWriter pw) {
137 switch (category) {
138 case Category.Symbol:
139 case Category.Numeric:
140 pw.print(o);
141 break;
142 case Category.String:
143 pw.print(Util.quoteForMdx((String) o));
144 break;
145 case Category.Null:
146 pw.print("NULL");
147 break;
148 default:
149 throw Util.newInternal("bad literal type " + category);
150 }
151 }
152
153 public int getCategory() {
154 return category;
155 }
156
157 public Type getType() {
158 switch (category) {
159 case Category.Symbol:
160 return new SymbolType();
161 case Category.Numeric:
162 return new NumericType();
163 case Category.String:
164 return new StringType();
165 case Category.Null:
166 return new NullType();
167 default:
168 throw Category.instance.badValue(category);
169 }
170 }
171
172 public Exp accept(Validator validator) {
173 return this;
174 }
175
176 public Calc accept(ExpCompiler compiler) {
177 return new ConstantCalc(getType(), o);
178 }
179
180 public Object accept(MdxVisitor visitor) {
181 return visitor.visit(this);
182 }
183
184 public Object getValue() {
185 return o;
186 }
187
188 public int getIntValue() {
189 if (o instanceof Number) {
190 return ((Number) o).intValue();
191 } else {
192 throw Util.newInternal("cannot convert " + o + " to int");
193 }
194 }
195
196 }
197
198 // End Literal.java