|
1
13 package com.tonbeller.wcf.expr;
14
15 import java.beans.PropertyDescriptor  ;
16 import java.lang.reflect.InvocationTargetException ;
17
18 import javax.servlet.jsp.PageContext ;
19
20 import org.apache.commons.beanutils.PropertyUtils;
21 import org.apache.log4j.Logger;
22
23 import com.tonbeller.wcf.utils.SoftException;
24
25
29 public class ExprUtils {
30 private static Logger logger = Logger.getLogger(ExprUtils.class);
31
32 private ExprUtils() {
33 super();
34 }
35
36 public static void checkExpr(String expr) {
37 if (expr == null)
38 throw new IllegalArgumentException ("expr is null");
39 if (isExpression(expr) && !expr.endsWith("}"))
40 throw new IllegalArgumentException ("expr must end with \"}\"");
41 }
42
43 public static Object getModelReference(PageContext pageContext, String expr) {
44 ExprContext ec = getExprContextAdapter(pageContext);
45 return getModelReference(ec, expr);
46
47 }
48
49 public static ExprContext getExprContextAdapter(final PageContext pageContext) {
50 return new ExprContext() {
51 public Object findBean(String name) {
52 return pageContext.findAttribute(name);
53 }
54 public void setBean(String name, Object bean) {
55 if (bean == null)
56 pageContext.removeAttribute(name);
57 else
58 pageContext.setAttribute(name, bean, PageContext.SESSION_SCOPE);
59 }
60 };
61 }
62
63 public static Object getModelReference(ExprContext context, String expr) {
64 try {
65 if (expr == null || expr.length() == 0)
66 return null;
67 if (!isExpression(expr))
69 return context.findBean(expr);
70
71 if (!expr.endsWith("}"))
72 throw new IllegalArgumentException ("expr must end with '}'");
73
74 int pos = expr.indexOf('.');
76 if (pos < 0) {
77 String name = expr.substring(2, expr.length() - 1);
79 return context.findBean(name);
80 }
81 String name = expr.substring(2, pos);
83 Object bean = context.findBean(name);
84 if (bean == null)
85 throw new IllegalArgumentException ("bean \"" + name + "\" not found");
86 String path = expr.substring(pos + 1, expr.length() - 1);
87 return PropertyUtils.getProperty(bean, path);
88 } catch (IllegalAccessException e) {
89 logger.error("?", e);
90 throw new SoftException(e);
91 } catch (InvocationTargetException e) {
92 logger.error("?", e);
93 throw new SoftException(e);
94 } catch (NoSuchMethodException e) {
95 logger.error("?", e);
96 throw new SoftException(e);
97 }
98 }
99
100 public static void setModelReference(ExprContext context, String expr, Object value) {
101 if (expr == null)
102 throw new NullPointerException ("expr is null");
103
104 if (!isExpression(expr)) {
106 context.setBean(expr, value);
107 return;
108 }
109
110 if (!expr.endsWith("}"))
111 throw new IllegalArgumentException ("expr must end with '}'");
112
113 if (expr.indexOf('.') < 0) {
115 String name = expr.substring(2, expr.length()- 1);
117 context.setBean(name, value);
118 return;
119 }
120
121 try {
123 int pos = expr.indexOf('.');
124 String name = expr.substring(2, pos);
125 Object bean = context.findBean(name);
126 if (bean == null)
127 throw new IllegalArgumentException ("bean \"" + name + "\" not found");
128 String path = expr.substring(pos + 1, expr.length() - 1);
129 PropertyUtils.setProperty(bean, path, value);
130 } catch (IllegalAccessException e) {
131 logger.error("exception caught", e);
132 throw new SoftException(e);
133 } catch (InvocationTargetException e) {
134 logger.error("exception caught", e);
135 throw new SoftException(e);
136 } catch (NoSuchMethodException e) {
137 logger.error("exception caught", e);
138 throw new SoftException(e);
139 }
140 }
141
142 public static PropertyDescriptor getPropertyDescriptor(ExprContext context, String expr) {
143 if (!ExprUtils.isExpression(expr) || !expr.endsWith("}") || expr.indexOf('.') < 0)
144 throw new IllegalArgumentException ("'#{bean.property}' expected");
145
146 int pos = expr.indexOf('.');
147 String name = expr.substring(2, pos);
148 Object bean = context.findBean(name);
149 if (bean == null)
150 throw new IllegalArgumentException ("bean \"" + name + "\" not found");
151 String path = expr.substring(pos + 1, expr.length() - 1);
152 try {
153 return PropertyUtils.getPropertyDescriptor(bean, path);
154 } catch (Exception e) {
155 logger.error(null, e);
156 return null;
157 }
158 }
159
160
164 public static String getBeanName(String expr) {
165 if (isExpression(expr))
166 expr = expr.substring(2, expr.length() - 1);
167 int pos = expr.indexOf('.');
168 if (pos > 0)
169 expr = expr.substring(0, pos);
170 return expr;
171 }
172
173
176 public static boolean isExpression(String expr) {
177 if (expr == null)
178 return false;
179 return expr.startsWith("${") || expr.startsWith("#{");
180 }
181
182 }
183 |
Popular Tags |
Java API By Example, From Geeks To Geeks.