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Java > Open Source Codes > org > objectstyle > cayenne > exp > parser > ASTSubtract


1 /* ====================================================================
2  *
3  * The ObjectStyle Group Software License, version 1.1
4  * ObjectStyle Group - http://objectstyle.org/
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6  * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
7  * of the software. All rights reserved.
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10  * modification, are permitted provided that the following conditions
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22  * must include the following acknowlegement:
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24  * and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
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26  * if and wherever such third-party acknowlegements normally appear.
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53  * information on the ObjectStyle Group, please see
54  * <http://objectstyle.org/>.
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56
57 package org.objectstyle.cayenne.exp.parser;
58
59 import java.math.BigDecimal JavaDoc;
60 import java.util.Collection JavaDoc;
61 import java.util.Iterator JavaDoc;
62
63 import org.objectstyle.cayenne.exp.Expression;
64 import org.objectstyle.cayenne.util.ConversionUtil;
65
66 /**
67  * "Subtract" expression.
68  *
69  * @since 1.1
70  * @author Andrei Adamchik
71  */

72 public class ASTSubtract extends SimpleNode {
73     ASTSubtract(int id) {
74         super(id);
75     }
76
77     public ASTSubtract() {
78         super(ExpressionParserTreeConstants.JJTSUBTRACT);
79     }
80
81     public ASTSubtract(Object JavaDoc[] nodes) {
82         super(ExpressionParserTreeConstants.JJTSUBTRACT);
83         int len = nodes.length;
84         for (int i = 0; i < len; i++) {
85             jjtAddChild(wrapChild(nodes[i]), i);
86         }
87     }
88
89     public ASTSubtract(Collection JavaDoc nodes) {
90         super(ExpressionParserTreeConstants.JJTSUBTRACT);
91         int len = nodes.size();
92         Iterator JavaDoc it = nodes.iterator();
93         for (int i = 0; i < len; i++) {
94             jjtAddChild(wrapChild(it.next()), i);
95         }
96     }
97
98     protected Object JavaDoc evaluateNode(Object JavaDoc o) throws Exception JavaDoc {
99         int len = jjtGetNumChildren();
100         if (len == 0) {
101             return null;
102         }
103
104         BigDecimal JavaDoc result = null;
105         for (int i = 0; i < len; i++) {
106             BigDecimal JavaDoc value = ConversionUtil.toBigDecimal(evaluateChild(i, o));
107
108             if (value == null) {
109                 return null;
110             }
111
112             result = (i == 0) ? value : result.subtract(value);
113         }
114
115         return result;
116     }
117
118     /**
119      * Creates a copy of this expression node, without copying children.
120      */

121     public Expression shallowCopy() {
122         return new ASTSubtract(id);
123     }
124
125     protected String JavaDoc getExpressionOperator(int index) {
126         return "-";
127     }
128
129     public int getType() {
130         return Expression.SUBTRACT;
131     }
132
133     public void jjtClose() {
134         super.jjtClose();
135         flattenTree();
136     }
137 }
138
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