01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: */
17:
18: package org.apache.el.lang;
19:
20: import javax.el.ValueExpression;
21: import javax.el.VariableMapper;
22:
23: public class VariableMapperFactory extends VariableMapper {
24:
25: private final VariableMapper target;
26: private VariableMapper momento;
27:
28: public VariableMapperFactory(VariableMapper target) {
29: if (target == null) {
30: throw new NullPointerException(
31: "Target VariableMapper cannot be null");
32: }
33: this .target = target;
34: }
35:
36: public VariableMapper create() {
37: return this .momento;
38: }
39:
40: public ValueExpression resolveVariable(String variable) {
41: ValueExpression expr = this .target.resolveVariable(variable);
42: if (expr != null) {
43: if (this .momento == null) {
44: this .momento = new VariableMapperImpl();
45: }
46: this .momento.setVariable(variable, expr);
47: }
48: return expr;
49: }
50:
51: public ValueExpression setVariable(String variable,
52: ValueExpression expression) {
53: throw new UnsupportedOperationException(
54: "Cannot Set Variables on Factory");
55: }
56: }
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