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1
56
57 package org.objectstyle.cayenne.exp;
58
59 import java.io.PrintWriter  ;
60 import java.util.ArrayList ;
61 import java.util.Collection ;
62 import java.util.List ;
63
64 import org.apache.commons.collections.Transformer;
65
66
72 public class ListExpression extends Expression {
73 protected List operands = new ArrayList ();
74
75 public ListExpression() {
76 }
77
78 public ListExpression(int type) {
79 this.type = type;
80 }
81
82 protected void flattenTree() {
83
84 }
85
86 protected boolean pruneNodeForPrunedChild(Object prunedChild) {
87 return false;
88 }
89
90 public Expression transform(Transformer transformer) {
91 Expression copy = super.transform(transformer);
92
93 if (!(copy instanceof ListExpression)) {
94 return copy;
95 }
96
97 switch (copy.getOperandCount()) {
100 case 1 :
101 return (Expression) copy.getOperand(0);
102 case 0 :
103 return null;
104 default :
105 return copy;
106 }
107 }
108
109
114 public Expression shallowCopy() {
115 return new ListExpression(type);
116 }
117
118
121 public int getOperandCount() {
122 return operands.size();
123 }
124
125
128 public Object getOperand(int index) {
129 if (operands.size() <= index) {
130 throw new IllegalArgumentException (
131 "Attempt to retrieve operand "
132 + index
133 + ", while current number of operands is "
134 + operands.size());
135 }
136
137 return operands.get(index);
138 }
139
140
143 public void setOperand(int index, Object value) {
144 if (operands.size() == index) {
145 appendOperand(value);
146 }
147 else if (operands.size() > index) {
148 operands.set(index, value);
149 }
150 else {
151 throw new IllegalArgumentException (
152 "Attempt to set operand "
153 + index
154 + ", while current number of operands is "
155 + operands.size());
156 }
157 }
158
159 public void appendOperand(Object value) {
160 operands.add(value);
161 }
162
163 public void appendOperands(Collection operands) {
164 this.operands.addAll(operands);
165 }
166
167 public void removeOperand(Object value) {
168 operands.remove(value);
169 }
170
171
177 public Expression joinExp(int type, Expression exp) {
178 if (type != this.type) {
179 return super.joinExp(type, exp);
180 }
181
182 ListExpression copy = new ListExpression();
184 copy.setType(type);
185 copy.appendOperands(operands);
186 copy.appendOperand(exp);
187
188 return copy;
189 }
190
191
194 public void encodeAsString(PrintWriter pw) {
195 StringBuffer buffer = new StringBuffer ();
198 toStringBuffer(buffer);
199 pw.print(buffer.toString());
200 }
201 }
202 |
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