01: /**
02: * Copyright 2006 Webmedia Group Ltd.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
10: * Unless required by applicable law or agreed to in writing, software
11: * distributed under the License is distributed on an "AS IS" BASIS,
12: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13: * See the License for the specific language governing permissions and
14: * limitations under the License.
15: **/package org.araneaframework.backend.list.memorybased.expression.string;
16:
17: import java.util.Iterator;
18: import org.araneaframework.backend.list.memorybased.Expression;
19: import org.araneaframework.backend.list.memorybased.ExpressionEvaluationException;
20: import org.araneaframework.backend.list.memorybased.expression.MultiExpression;
21: import org.araneaframework.backend.list.memorybased.expression.VariableResolver;
22:
23: /**
24: * Concatenating composite expression, evaluates all subexpressions and concatenates results into a String.
25: */
26: public class ConcatenationExpression extends MultiExpression {
27: private static final long serialVersionUID = 1L;
28:
29: /**
30: * @return subexpressions evaluation results in a concatenated String.
31: * @see org.araneaframework.backend.list.memorybased.Expression#evaluate(org.araneaframework.backend.list.memorybased.expression.VariableResolver)
32: */
33: public Object evaluate(VariableResolver resolver)
34: throws ExpressionEvaluationException {
35: if (this .children.size() == 0) {
36: throw new ExpressionEvaluationException(
37: "At least one children must be provided");
38: }
39: StringBuffer buffer = new StringBuffer();
40: for (Iterator i = this .children.iterator(); i.hasNext();) {
41: Expression child = (Expression) i.next();
42: buffer.append(child.evaluate(resolver));
43: }
44: return buffer.toString();
45: }
46: }
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