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Java > Open Source Codes > com > quadcap > sql > BinaryExpression


1 package com.quadcap.sql;
2
3 /* Copyright 1999 - 2003 Quadcap Software. All rights reserved.
4  *
5  * This software is distributed under the Quadcap Free Software License.
6  * This software may be used or modified for any purpose, personal or
7  * commercial. Open Source redistributions are permitted. Commercial
8  * redistribution of larger works derived from, or works which bundle
9  * this software requires a "Commercial Redistribution License"; see
10  * http://www.quadcap.com/purchase.
11  *
12  * Redistributions qualify as "Open Source" under one of the following terms:
13  *
14  * Redistributions are made at no charge beyond the reasonable cost of
15  * materials and delivery.
16  *
17  * Redistributions are accompanied by a copy of the Source Code or by an
18  * irrevocable offer to provide a copy of the Source Code for up to three
19  * years at the cost of materials and delivery. Such redistributions
20  * must allow further use, modification, and redistribution of the Source
21  * Code under substantially the same terms as this license.
22  *
23  * Redistributions of source code must retain the copyright notices as they
24  * appear in each source code file, these license terms, and the
25  * disclaimer/limitation of liability set forth as paragraph 6 below.
26  *
27  * Redistributions in binary form must reproduce this Copyright Notice,
28  * these license terms, and the disclaimer/limitation of liability set
29  * forth as paragraph 6 below, in the documentation and/or other materials
30  * provided with the distribution.
31  *
32  * The Software is provided on an "AS IS" basis. No warranty is
33  * provided that the Software is free of defects, or fit for a
34  * particular purpose.
35  *
36  * Limitation of Liability. Quadcap Software shall not be liable
37  * for any damages suffered by the Licensee or any third party resulting
38  * from use of the Software.
39  */
40
41 import java.io.Externalizable JavaDoc;
42 import java.io.IOException JavaDoc;
43 import java.io.ObjectInput JavaDoc;
44 import java.io.ObjectOutput JavaDoc;
45
46 import java.util.Enumeration JavaDoc;
47 import java.util.Vector JavaDoc;
48
49 import java.sql.SQLException JavaDoc;
50
51 import com.quadcap.sql.types.Op;
52 import com.quadcap.sql.types.Type;
53 import com.quadcap.sql.types.Value;
54
55 import com.quadcap.util.Debug;
56
57 /**
58  * Expression class for all binary ops.
59  *
60  * @author Stan Bailes
61  */
62 public class BinaryExpression extends Expression implements Externalizable JavaDoc {
63     Expression e = null;
64     Expression f = null;
65     int op = -1;
66     boolean not = false;
67
68     /**
69      * Default constructor
70      */
71     public BinaryExpression() {}
72
73     /**
74      * Parser's constructor: A binary expression node consists of an opcode and two
75      * "child" expressions.
76      */
77     public BinaryExpression(int op, Expression e, Expression f) {
78     this.op = op;
79     this.e = e;
80     this.f = f;
81     }
82
83     public int rank() { return 0; }
84
85     public Type getType(Session session, Cursor cursor) throws SQLException JavaDoc {
86         return e.getType(session, cursor); // XXX not quite...
87 }
88
89     public Value getValue(Session session, Cursor cursor) throws SQLException JavaDoc {
90     Value eval = e.getValue(session, cursor);
91     Value fval = f.getValue(session, cursor);
92         Value ret = Value.binop(op, eval, fval);
93     if (not) {
94         ret = ret.unop(Op.NOT);
95     }
96     return ret;
97     }
98     
99     public void invert() {
100     not = !not;
101     }
102
103     public String JavaDoc toString() {
104     String JavaDoc n = not ? "not " : "";
105     return n + e + " " + Op.toString(op) + " " + f;
106     }
107
108     public void visitSubExpressions(ExpressionVisitor ev) {
109     ev.visit(e);
110     ev.visit(f);
111     }
112
113     public void readExternal(ObjectInput JavaDoc in)
114     throws IOException JavaDoc, ClassNotFoundException JavaDoc
115     {
116     e = (Expression)in.readObject();
117     f = (Expression)in.readObject();
118     op = in.readInt();
119     not = (in.read() == 1);
120     }
121     
122     public void writeExternal(ObjectOutput JavaDoc out) throws IOException JavaDoc {
123     out.writeObject(e);
124     out.writeObject(f);
125     out.writeInt(op);
126     out.write(not ? 1 : 0);
127     }
128 }
129
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