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1
28
29 package com.caucho.jsp.java;
30
31 import com.caucho.jsp.JspParseException;
32 import com.caucho.vfs.WriteStream;
33 import com.caucho.xml.QName;
34
35 import java.io.IOException  ;
36 import java.lang.reflect.Constructor ;
37 import java.lang.reflect.Modifier ;
38
39
42 public class JspUseBean extends JspContainerNode {
43 private static final QName ID = new QName("id");
44 private static final QName TYPE = new QName("type");
45 private static final QName CLASS = new QName("class");
46 private static final QName BEAN_NAME = new QName("beanName");
47 private static final QName SCOPE = new QName("scope");
48
49 private String _id;
50 private String _typeName;
51 private String _className;
52 private String _beanName;
53 private String _scope;
54
55
58 public void addAttribute(QName name, String value)
59 throws JspParseException
60 {
61 if (ID.equals(name))
62 _id = value;
63 else if (TYPE.equals(name))
64 _typeName = value;
65 else if (CLASS.equals(name))
66 _className = value;
67 else if (BEAN_NAME.equals(name))
68 _beanName = value;
69 else if (SCOPE.equals(name))
70 _scope = value;
71 else
72 throw error(L.l("'{0}' is an invalid attribute in <jsp:useBean>",
73 name.getName()));
74 }
75
76
79 public JspNode addText(String text)
80 throws JspParseException
81 {
82 JspNode node = new StaticText(_gen, text, this);
83
84 addChild(node);
85
86 return node;
87 }
88
89
94 public void printXml(WriteStream os)
95 throws IOException
96 {
97 os.print("<jsp:userBean");
98
99 if (_id != null)
100 os.print(" id=\"" + _id + "\"");
101 if (_typeName != null)
102 os.print(" type=\"" + _typeName + "\"");
103 if (_className != null)
104 os.print(" class=\"" + _className + "\"");
105 if (_beanName != null)
106 os.print(" beanName=\"" + _beanName + "\"");
107 if (_scope != null)
108 os.print(" scope=\"" + _scope + "\"");
109 os.print("/>");
110 }
111
112
117 public void generate(JspJavaWriter out)
118 throws Exception
119 {
120 if (_id == null)
121 throw error(L.l("<jsp:useBean> expects an 'id' attribute. id specifies the variable name for the bean."));
122
123 if (_typeName == null)
124 _typeName = _className;
125
126 if (_typeName == null)
127 throw error(L.l("<jsp:useBean> expects a 'type' or 'class' attribute. The 'type' specifies the Java type of the bean."));
128
129 _gen.addBeanClass(_id, _typeName);
131
132 String context = null;
133 if (_scope == null || _scope.equals("page"))
134 context = "pageContext";
135 else if (_scope.equals("request")) {
136 context = "pageContext.getRequest()";
137 }
138 else if (_scope.equals("session")) {
139 context = "pageContext.getSession()";
140 }
141 else if (_scope.equals("application")) {
142 context = "pageContext.getApplication()";
143 }
144 else
145 throw error(L.l("Unknown scope '{0}' in <jsp:useBean>. Scope must be 'page', 'request', 'session', or 'application'.", _scope));
146
147 out.println(_typeName + " " + _id + ";");
149
150 if ("application".equals(_scope) || "session".equals(_scope)) {
152 out.println("synchronized (" + context + ") {");
153 out.pushDepth();
154 }
155
156 out.print(_id + " = (" + _typeName + ") " + context);
158 out.println(".getAttribute(\"" + _id + "\");");
159
160 out.println("if (" + _id + " == null) {");
162 out.pushDepth();
163
164 boolean canInstantiate = false;
165
166 if (_className != null) {
168 String msg = canInstantiateBean(_className);
169 if (msg == null) {
170 out.println(_id + " = new " + _className + "();");
171 canInstantiate = true;
172 }
173 else
174 out.println("throw new java.lang.InstantiationException(\"" + msg + "\");");
175 }
176 else if (_beanName == null)
177 out.println("throw new java.lang.InstantiationException(\"jsp:useBean needs 'bean' or 'class'\");");
178 else if (hasRuntimeAttribute(_beanName)) {
180 String beanName = getRuntimeAttribute(_beanName);
181 out.println(_id + " = (" + _typeName +
182 ") java.beans.Beans.instantiate(getClass().getClassLoader(), " +
183 beanName + ");");
184 canInstantiate = true;
185 }
186 else {
188 out.println(_id + " = (" + _typeName +
189 ") java.beans.Beans.instantiate(getClass().getClassLoader(), \"" +
190 _beanName + "\");");
191 canInstantiate = true;
192 }
193
194 if (! canInstantiate) {
196 }
197 else
198 out.println(context + ".setAttribute(\"" + _id + "\", " + _id + ");");
199
200 if (canInstantiate)
202 generateChildren(out);
203
204 out.popDepth();
205 out.println("}");
206
207 if ("application".equals(_scope) || "session".equals(_scope)) {
209 out.popDepth();
210 out.println("}");
211 }
212 }
213
214
217 private String canInstantiateBean(String className)
218 throws Exception
219 {
220 try {
221 Class cl = _gen.getBeanClass(className);
222 int modifiers = cl.getModifiers();
223 if (Modifier.isInterface(modifiers))
224 return L.l("'{0}' is an interface", className);
225 if (Modifier.isAbstract(modifiers))
226 return L.l("'{0}' is abstract", className);
227 if (! Modifier.isPublic(modifiers))
228 return L.l("'{0}' must be public", className);
229
230 Constructor []constructors = cl.getConstructors();
231 for (int i = 0; i < constructors.length; i++) {
232
233 Class []param = constructors[i].getParameterTypes();
234 if (param.length == 0)
235 return null;
236 }
237 } catch (Exception e) {
238 throw error(e.getMessage());
239 }
240
241 return L.l("'{0}' has no public zero-arg constructor", className);
242 }
243 }
244 |
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