1 /*
2 * Copyright 2002-2013 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
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 */
16
17 package org.springframework.expression;
18
19 /**
20 * Input provided to an expression parser that can influence an expression
21 * parsing/compilation routine.
22 *
23 * @author Keith Donald
24 * @author Andy Clement
25 * @since 3.0
26 */
27 public interface ParserContext {
28
29 /**
30 * Whether or not the expression being parsed is a template. A template expression
31 * consists of literal text that can be mixed with evaluatable blocks. Some examples:
32 * <pre class="code">
33 * Some literal text
34 * Hello #{name.firstName}!
35 * #{3 + 4}
36 * </pre>
37 * @return true if the expression is a template, false otherwise
38 */
39 boolean isTemplate();
40
41 /**
42 * For template expressions, returns the prefix that identifies the start of an
43 * expression block within a string. For example: "${"
44 * @return the prefix that identifies the start of an expression
45 */
46 String getExpressionPrefix();
47
48 /**
49 * For template expressions, return the prefix that identifies the end of an
50 * expression block within a string. For example: "}"
51 * @return the suffix that identifies the end of an expression
52 */
53 String getExpressionSuffix();
54
55
56 /**
57 * The default ParserContext implementation that enables template expression parsing
58 * mode. The expression prefix is #{ and the expression suffix is }.
59 * @see #isTemplate()
60 */
61 public static final ParserContext TEMPLATE_EXPRESSION = new ParserContext() {
62
63 @Override
64 public String getExpressionPrefix() {
65 return "#{";
66 }
67
68 @Override
69 public String getExpressionSuffix() {
70 return "}";
71 }
72
73 @Override
74 public boolean isTemplate() {
75 return true;
76 }
77
78 };
79
80 }