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("
WebConfig:
");
sb.append("
Field name
Type
Description
Value
\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("
");
sb.append("
").append( field.getName() ).append("
");
sb.append("
").append( field.getType().getName() ).append("
");
sb.append("
").append( anno.description() ).append("
");
sb.append("
\n");
}
sb.append("
\n\n");
Method[] methods = configObject.getClass().getDeclaredMethods();
for(Method method : methods) {
method.setAccessible(true);
ReloadConfig anno = method.getAnnotation(ReloadConfig.class);
if (anno == null)
continue;
sb.append("\n");
}
} catch (IllegalAccessException e) {
throw new ServletException(e);
}
sb.append("");
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);
ReloadConfig anno = method.getAnnotation(ReloadConfig.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;
}
if (field.getType().getName().equals("int") ) {
field.setInt(configObject, Integer.parseInt(value) );
} else if (field.getType().getName().equals("boolean") ) {
value = value.toLowerCase();
if (! (value.equals("true") || value.equals("false"))) {
resp.sendError(500, "Only 'true' or 'false' as values for boolean field");
return;
}
field.setBoolean(configObject, Boolean.parseBoolean(value) );
} else if (field.getType().getName().equals("long") ) {
field.setLong(configObject, Long.parseLong(value) );
} else if (field.getType().getName().equals("short") ) {
field.setShort(configObject, Short.parseShort(value) );
} else if (field.getType().getName().equals("double") ) {
field.setDouble(configObject, Double.parseDouble(value) );
} else if (field.getType().getName().equals("float") ) {
field.setFloat(configObject, Float.parseFloat(value) );
} else if (field.getType().getName().equals("char") ) {
field.setFloat(configObject, value.charAt(0) );
} else {
field.set(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() );
}
}