1 package uba.db.sql.language;
2
3 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.BooleanType;
4
5 /***
6 * Representa un criterio de seleccion (parte <i>WHERE </i> de una expresión
7 * SQL) vacío (es decir representa que se deben seleccionar todas las filas).
8 *
9 * @version $Revision: 1.5 $
10 */
11 public final class NullSelectionCriteria implements SelectionCriteria {
12 /***
13 * @see java.lang.Object#hashCode()
14 */
15 public int hashCode() {
16 return getClass().hashCode();
17 }
18
19 /***
20 * @see java.lang.Object#equals(java.lang.Object)
21 */
22 public boolean equals(Object obj) {
23 return obj == this || (obj != null && obj.getClass().equals(getClass()));
24 }
25
26 /***
27 * @see java.lang.Object#toString()
28 */
29 public String toString() {
30 return "";
31 }
32
33 /***
34 * @see uba.db.sql.language.Visitable#accept(uba.db.sql.language.Visitor)
35 */
36 public void accept(Visitor visitor) {}
37
38 /***
39 * @see uba.db.sql.language.SelectionCriteria#and(uba.db.sql.language.SelectionCriteria)
40 */
41 public SelectionCriteria and(SelectionCriteria otherSelectionCriteria) {
42 return otherSelectionCriteria;
43 }
44
45 /***
46 * @see uba.db.sql.language.SelectionCriteria#or(uba.db.sql.language.SelectionCriteria)
47 */
48 public SelectionCriteria or(SelectionCriteria otherSelectionCriteria) {
49 return otherSelectionCriteria;
50 }
51
52 /***
53 * @see uba.db.sql.language.SelectionCriteria#not()
54 */
55 public SelectionCriteria not() {
56 return this;
57 }
58
59 /***
60 * @see uba.db.sql.language.SelectionCriteria#andAfter(uba.db.sql.language.SelectionCriteria)
61 */
62 public SelectionCriteria andAfter(SelectionCriteria other) {
63 return other;
64 }
65
66 /***
67 * @see uba.db.sql.language.SelectionCriteria#orAfter(uba.db.sql.language.SelectionCriteria)
68 */
69 public SelectionCriteria orAfter(SelectionCriteria other) {
70 return other;
71 }
72
73 /***
74 * @see uba.db.sql.language.SelectionCriteria#valueWith(uba.db.sql.language.EvaluationContext)
75 */
76 public Object valueWith(EvaluationContext context) {
77 return Boolean.TRUE;
78 }
79
80 /***
81 * @see uba.db.sql.language.SelectionCriteria#isTrueWith(uba.db.sql.language.EvaluationContext)
82 */
83 public boolean isTrueWith(EvaluationContext context) {
84 return true;
85 }
86 }