thoerup/webconfig/ConfigServlet.java

package dk.thoerup.webconfig;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ConfigServlet extends HttpServlet {
        private static final long serialVersionUID = 1L;
        
        private Object configObject;
        
        public void setConfigObject(Object obj) {
                configObject = obj;
        }
        
        
        @Override
        public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
                
                
                resp.setDateHeader("Expires", 0); 
                resp.setHeader("Pragma", "no-cache");
                resp.setHeader("Cache-Control", "no-cache");
                resp.setContentType("text/html");
                
                StringBuilder sb = new StringBuilder();
                
                sb.append("<html><body><h3>WebConfig:</h3><table border='1' cellspacing='0'>");
                sb.append("<tr><th>Field name</th><th>Type</th><th>Description</th><th>Value</th><th>&nbsp;</th></tr>\n"); 
                
                
                Field fields[] = configObject.getClass().getDeclaredFields();
                
                try {
                        for(Field field : fields) {
                                field.setAccessible(true);

                                ConfigVariable anno = field.getAnnotation(ConfigVariable.class);
                                if (anno == null)
                                        continue;
                                
                                sb.append("<tr>");
                                sb.append("<td>").append( field.getName() ).append("</td>");
                                sb.append("<td>").append( field.getType().getName() ).append("</td>");
                                sb.append("<td>").append( anno.description() ).append("&nbsp;</td>");
                                
                                sb.append("<form action='").append( req.getRequestURI() ).append("' method='post'>");
                                sb.append("<input type='hidden' name='varname' value='").append( field.getName() ).append("' />");
                                
                                                                
                                
                                
                                if (anno.readonly() == false) {
                                        if (field.getType().getName().equals("boolean") ) {
                        String trueSelected = field.get(configObject).toString().equals("true") ? " selected " : "";
                        String falseSelected = field.get(configObject).toString().equals("false") ? " selected " : "";
                        String options = String.format("<option %s>true</option><option %s>false</option>", trueSelected, falseSelected);
                        sb.append("<td><select name='varvalue'>").append(options).append("</select></td>");
                    } else {
                        sb.append("<td><input type='text' name='varvalue' value='").append( "" + field.get(configObject) ).append("' /></td>");
                    }
                                        sb.append("<td><input type='submit' name='Set' value='Set'></td>\n");
                                } else {
                                        sb.append("<td>").append( ""+ field.get(configObject) ).append("&nbsp;</td>");
                                        sb.append("<td>&nbsp;</td>");
                                }
                                
                                sb.append("</form></tr>\n");                            
                        }
                        
                        sb.append("</table>\n\n");
                        
                        Method[] methods = configObject.getClass().getDeclaredMethods();
                        for(Method method : methods) {
                                method.setAccessible(true);
                                
                                ReloadConfigMethod anno = method.getAnnotation(ReloadConfigMethod.class);
                                if (anno == null)
                                        continue;
                                
                                sb.append("<form method='post' action='").append( req.getRequestURI() ).append("'>");
                                sb.append("<input type='hidden' name='reloadmethod' value='").append(method.getName()).append("'>");
                                sb.append("<input type='submit' name='Reload Config' value='Reload Config'>");
                                sb.append("</form>\n");
                                
                        }
                        
                                                
                } catch (IllegalAccessException e) {
                        throw new ServletException(e);
                }
                
                sb.append("</body></html>");
                
                resp.getWriter().print( sb.toString() );
        }

        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
                String name = req.getParameter("varname");
                String value = req.getParameter("varvalue");
                
                String reloadmethod = req.getParameter("reloadmethod");
                
                try {                   
                        if (reloadmethod != null) { //reload
                                
                                Method method = configObject.getClass().getDeclaredMethod(reloadmethod, (Class<?>[]) null);
                                ReloadConfigMethod anno = method.getAnnotation(ReloadConfigMethod.class);
                                if (anno == null) {
                                        resp.sendError(500, "Method is not annotated");
                                        return;
                                }
                                        
                                
                                method.setAccessible(true);                                                             
                                method.invoke(configObject, (Object[])null);                            
                                
                        } else { //set var                                      
                                value = value.trim();
                                Field field = configObject.getClass().getDeclaredField(name);
                                field.setAccessible(true);
                                ConfigVariable anno = field.getAnnotation(ConfigVariable.class);
                                
                                if (anno == null) {
                                        resp.sendError(500, "Field is not annotated");
                                        return;
                                }                               
                                
                                if (anno.readonly() == true) {
                                        resp.sendError(500, "Can't write a read-only field");
                                        return;
                                }
        
                                ConfigLoader.setFieldValue(field,configObject,value);
                                
                                
                        } //end of set var
                                
                        
                } catch (NoSuchFieldException e) {
                        resp.sendError(500, "No such field: " + name);
                } catch (IllegalAccessException e) { //this can't happen
                        throw new ServletException(e); 
                } catch (NoSuchMethodException e) {
                        resp.sendError(500, "No such method: " + reloadmethod);
                } catch (InvocationTargetException e) {
                        resp.sendError(500, "Could not invoke method: " + reloadmethod);
                }
                
                resp.sendRedirect( req.getRequestURI() );               
        }

}
1	torben	1319	package dk.thoerup.webconfig;
2
3			import java.io.IOException;
4			import java.lang.reflect.Field;
5	torben	1328	import java.lang.reflect.InvocationTargetException;
6			import java.lang.reflect.Method;
7	torben	1319
8			import javax.servlet.ServletException;
9			import javax.servlet.http.HttpServlet;
10			import javax.servlet.http.HttpServletRequest;
11			import javax.servlet.http.HttpServletResponse;
12
13			public class ConfigServlet extends HttpServlet {
14			private static final long serialVersionUID = 1L;
15
16			private Object configObject;
17
18			public void setConfigObject(Object obj) {
19			configObject = obj;
20			}
21
22
23			@Override
24			public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
25
26
27			resp.setDateHeader("Expires", 0);
28			resp.setHeader("Pragma", "no-cache");
29			resp.setHeader("Cache-Control", "no-cache");
30			resp.setContentType("text/html");
31
32			StringBuilder sb = new StringBuilder();
33
34			sb.append("<html><body><h3>WebConfig:</h3><table border='1' cellspacing='0'>");
35			sb.append("<tr><th>Field name</th><th>Type</th><th>Description</th><th>Value</th><th> </th></tr>\n");
36
37
38			Field fields[] = configObject.getClass().getDeclaredFields();
39
40			try {
41			for(Field field : fields) {
42			field.setAccessible(true);
43
44			ConfigVariable anno = field.getAnnotation(ConfigVariable.class);
45			if (anno == null)
46			continue;
47
48			sb.append("<tr>");
49			sb.append("<td>").append( field.getName() ).append("</td>");
50			sb.append("<td>").append( field.getType().getName() ).append("</td>");
51			sb.append("<td>").append( anno.description() ).append(" </td>");
52
53			sb.append("<form action='").append( req.getRequestURI() ).append("' method='post'>");
54			sb.append("<input type='hidden' name='varname' value='").append( field.getName() ).append("' />");
55
56	torben	1324
57
58
59			if (anno.readonly() == false) {
60	torben	1338	if (field.getType().getName().equals("boolean") ) {
61			String trueSelected = field.get(configObject).toString().equals("true") ? " selected " : "";
62			String falseSelected = field.get(configObject).toString().equals("false") ? " selected " : "";
63			String options = String.format("<option %s>true</option><option %s>false</option>", trueSelected, falseSelected);
64			sb.append("<td><select name='varvalue'>").append(options).append("</select></td>");
65			} else {
66			sb.append("<td><input type='text' name='varvalue' value='").append( "" + field.get(configObject) ).append("' /></td>");
67			}
68	torben	1319	sb.append("<td><input type='submit' name='Set' value='Set'></td>\n");
69	torben	1324	} else {
70			sb.append("<td>").append( ""+ field.get(configObject) ).append(" </td>");
71	torben	1319	sb.append("<td> </td>");
72	torben	1324	}
73	torben	1319
74	torben	1328	sb.append("</form></tr>\n");
75			}
76
77			sb.append("</table>\n\n");
78
79			Method[] methods = configObject.getClass().getDeclaredMethods();
80			for(Method method : methods) {
81			method.setAccessible(true);
82	torben	1319
83	torben	1344	ReloadConfigMethod anno = method.getAnnotation(ReloadConfigMethod.class);
84	torben	1328	if (anno == null)
85			continue;
86	torben	1319
87	torben	1328	sb.append("<form method='post' action='").append( req.getRequestURI() ).append("'>");
88			sb.append("<input type='hidden' name='reloadmethod' value='").append(method.getName()).append("'>");
89			sb.append("<input type='submit' name='Reload Config' value='Reload Config'>");
90			sb.append("</form>\n");
91	torben	1319
92	torben	1328	}
93	torben	1319
94	torben	1328
95	torben	1319	} catch (IllegalAccessException e) {
96			throw new ServletException(e);
97			}
98
99	torben	1328	sb.append("</body></html>");
100	torben	1319
101			resp.getWriter().print( sb.toString() );
102			}
103
104			@Override
105			protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
106			String name = req.getParameter("varname");
107	torben	1328	String value = req.getParameter("varvalue");
108	torben	1319
109	torben	1328	String reloadmethod = req.getParameter("reloadmethod");
110
111	torben	1319	try {
112	torben	1328	if (reloadmethod != null) { //reload
113
114			Method method = configObject.getClass().getDeclaredMethod(reloadmethod, (Class<?>[]) null);
115	torben	1344	ReloadConfigMethod anno = method.getAnnotation(ReloadConfigMethod.class);
116	torben	1329	if (anno == null) {
117			resp.sendError(500, "Method is not annotated");
118			return;
119			}
120
121
122			method.setAccessible(true);
123	torben	1328	method.invoke(configObject, (Object[])null);
124
125			} else { //set var
126			value = value.trim();
127			Field field = configObject.getClass().getDeclaredField(name);
128			field.setAccessible(true);
129			ConfigVariable anno = field.getAnnotation(ConfigVariable.class);
130
131			if (anno == null) {
132			resp.sendError(500, "Field is not annotated");
133	torben	1326	return;
134	torben	1328	}
135
136			if (anno.readonly() == true) {
137			resp.sendError(500, "Can't write a read-only field");
138			return;
139	torben	1326	}
140	torben	1328
141	torben	1339	ConfigLoader.setFieldValue(field,configObject,value);
142	torben	1319
143	torben	1328
144			} //end of set var
145
146	torben	1319
147			} catch (NoSuchFieldException e) {
148	torben	1321	resp.sendError(500, "No such field: " + name);
149	torben	1319	} catch (IllegalAccessException e) { //this can't happen
150			throw new ServletException(e);
151	torben	1328	} catch (NoSuchMethodException e) {
152			resp.sendError(500, "No such method: " + reloadmethod);
153			} catch (InvocationTargetException e) {
154			resp.sendError(500, "Could not invoke method: " + reloadmethod);
155	torben	1319	}
156
157			resp.sendRedirect( req.getRequestURI() );
158			}
159
160			}