|
1 package example;
2
3 import com.caucho.util.ThreadPool;
4 import com.caucho.util.ThreadTask;
5
6 import java.io.*;
7
8 import java.text.DateFormat  ;
9 import java.text.NumberFormat ;
10
11 import java.util.Date ;
12 import java.util.logging.Level ;
13 import java.util.logging.Logger ;
14
15 import java.util.concurrent.Executor ;
16
17 import javax.annotation.Resource;
18
19 import javax.servlet.*;
20 import javax.servlet.http.*;
21
22
25 public class PeriodicTaskServlet extends HttpServlet {
26 static protected final Logger log =
27 Logger.getLogger(PeriodicTaskServlet.class.getName());
28
29 int _refreshRate = 5;
30
31 @Resource
32 private Executor _executor;
33
34 private PeriodicTask _periodicTask;
35
36 private NumberFormat _numberFormat ;
37 private DateFormat _dateFormat ;
38
39 public PeriodicTaskServlet()
40 {
41 }
42
43 public void setPeriodicTask(PeriodicTask periodicTask)
44 {
45 _periodicTask = periodicTask;
46 }
47
48
52 public void setRefreshRate(int refreshRate)
53 {
54 _refreshRate = 5;
55 }
56
57 public void init()
58 throws ServletException
59 {
60 _numberFormat = NumberFormat.getInstance();
61 _dateFormat = DateFormat.getInstance();
62
63 String p;
64
65 p = getInitParameter("refresh-rate");
66 if (p != null)
67 setRefreshRate(Integer.parseInt(p));
68
69 if (_periodicTask == null)
70 throw new ServletException("`period-task' is required");
71 }
72
73 protected void doGet(HttpServletRequest request, HttpServletResponse response)
74 throws ServletException, IOException
75 {
76 final PeriodicTask task = _periodicTask;
77
78 String msg = null;
79
80 if (request.getParameter("RUN") != null) {
81 if (task.isActive())
82 msg = "Already active.";
83 else {
84 ThreadTask threadTask = new ThreadTask() {
88 public void run()
89 {
90 task.run();
91 }
92 };
93 _executor.execute(threadTask);
94 Thread.yield();
95 response.sendRedirect(request.getRequestURI());
96 }
97 }
98
99 response.setContentType("text/html");
100 PrintWriter out = response.getWriter();
101
102 response.setHeader("Cache-Control","no-cache,post-check=0,pre-check=0");
104 response.setHeader("Pragma","no-cache");
105 response.setHeader("Expires","Thu,01Dec199416:00:00GMT");
106
107 if (_refreshRate > 0) {
108 response.addHeader( "refresh", String.valueOf(_refreshRate) + "; URL=" + request.getRequestURI());
109 }
110
111 out.println("<html>");
112 out.println("<head><title>PeriodicTask</title></head>");
113 out.println("<body>");
114 out.println("<h1>PeriodicTask</h1>");
115
116 if (msg != null) {
117 out.print("<p><b>");
118 printSafeHtml(out,msg);
119 out.println("</b></p>");
120 }
121
122 out.println("<table border='0'>");
123
124 printHeading(out,"configuration");
125
126 printPeriod(out,"estimated-average-time:", task.getEstimatedAverageTime());
127
128 printHeading(out,"statistics");
129
130 printField(out,"active", task.isActive());
131 printPeriod(out,"estimated-time-remaining",task.getEstimatedTimeRemaining());
132 printDate(out,"last-active-time", task.getLastActiveTime());
133 printField(out,"total-active-count", task.getTotalActiveCount());
134 printPeriod(out,"total-active-time", task.getTotalActiveTime());
135 printPeriod(out,"average-active-time", task.getAverageActiveTime());
136
137 printHeading(out,"actions");
138 printActions(out,new String [][] { {"RUN", "Run"} });
139
140 out.println("</table border='0'>");
141
142
143 out.println("</body>");
144 out.println("</html>");
145 }
146
147 protected void printHeading(PrintWriter out, String heading)
148 {
149 out.print("<tr><td colspan='2'><h2>");
150 printSafeHtml(out,heading);
151 out.println("</h2></td></tr>");
152 }
153
154 protected void printField(PrintWriter out, String name, String value)
155 {
156 out.print("<tr><td>");
157 printSafeHtml(out,name);
158 out.print("</td><td>");
159 printSafeHtml(out,value);
160 out.print("</td></tr>");
161 }
162
163 protected void printField(PrintWriter out, String name, boolean value)
164 {
165 printField(out,name, value == true ? "true" : "false");
166 }
167
168 protected void printField(PrintWriter out, String name, long value)
169 {
170 printField(out,name, _numberFormat.format(value));
171 }
172 protected void printDate(PrintWriter out, String name, long date)
173 {
174 printField(out,name, _dateFormat.format(new Date (date)));
175 }
176
177 protected void printPeriod(PrintWriter out, String name, long millis)
178 {
179 double sec = millis / 1000;
180 printField(out,name, _numberFormat.format(millis) + "sec");
181 }
182
183 protected void printActions(PrintWriter out, String [][] actions)
184 {
185 out.println("<tr><td colspan='2'><form>");
186 for (int i = 0; i < actions.length; i++) {
187 out.print("<input type='submit' name='");
188 printSafeHtml(out,actions[i][0]);
189 out.print("' value='");
190 printSafeHtml(out,actions[i][1]);
191 out.println("'/>");
192 }
193 out.println("</form></td></tr>");
194 }
195
196 protected void printSafeHtml(PrintWriter out, String text)
197 {
198 int len = text.length();
199
200 for (int i = 0; i < len; i++) {
201 char ch = text.charAt(i);
202 switch (ch) {
203 case '<':
204 out.print("<");
205 break;
206 case '>':
207 out.print(">");
208 break;
209 case '&':
210 out.print("&");
211 break;
212 default:
213 out.print(ch);
214 }
215 }
216 }
217 }
218 |
Popular Tags |
Java API By Example, From Geeks To Geeks.