| /* |
| * Copyright 1999,2004 The Apache Software Foundation. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package factor; |
| |
| import org.apache.log4j.Logger; |
| import org.apache.log4j.NDC; |
| import org.apache.log4j.PropertyConfigurator; |
| |
| import java.rmi.Naming; |
| import java.rmi.RemoteException; |
| import java.rmi.server.UnicastRemoteObject; |
| |
| import java.util.Vector; |
| |
| |
| /** |
| A simple {@link NumberCruncher} implementation that logs its |
| progress when factoring numbers. The purpose of the whole exercise |
| is to show the use of nested diagnostic contexts in order to |
| distinguish the log output from different client requests. |
| |
| <pre> |
| <b>Usage:</b> java org.apache.log4j.examples.NumberCruncherServer <em>configFile</em> |
| where <em>configFile</em> is a log4j configuration file. |
| </pre> |
| |
| We supply a simple config file <a href=doc-files/factor.lcf>factor.lcf</a> |
| for directing log output to the file <code>factor.log</code>. |
| |
| <p>Try it yourself by starting a <code>NumberCruncherServer</code> |
| and make queries from multiple {@link NumberCruncherClient |
| NumberCruncherClients} to factor numbers. |
| |
| |
| <p><b><a href="doc-files/factor.html">Sample output</a></b> shows the log |
| output when two clients connect to the server near simultaneously. |
| |
| <p>See <a href=doc-files/NumberCruncherServer.java>source</a> code |
| of <code>NumberCruncherServer</code> for more details. |
| |
| <p>Note that class files for the example code is not included in |
| any of the distributed log4j jar files. You will have to add the |
| directory <code>/dir-where-you-unpacked-log4j/classes</code> to |
| your classpath before trying out the examples. |
| |
| |
| */ |
| public class NumberCruncherServer extends UnicastRemoteObject |
| implements NumberCruncher { |
| final static Logger logger = Logger.getLogger(NumberCruncherServer.class); |
| |
| public NumberCruncherServer() throws RemoteException { |
| } |
| |
| public int[] factor(int number) throws RemoteException { |
| // The client's host is an important source of information. |
| try { |
| NDC.push(getClientHost()); |
| } catch (java.rmi.server.ServerNotActiveException e) { |
| // we are being called from same VM |
| NDC.push("localhost"); |
| } |
| |
| // The information contained within the request is another source of |
| // distinctive information. It might reveal the users name, date of request, |
| // request ID etc. In servlet type environments, much information is |
| // contained in cookies. |
| NDC.push(String.valueOf(number)); |
| |
| logger.info("Beginning to factor."); |
| |
| if (number <= 0) { |
| throw new IllegalArgumentException( |
| number + " is not a positive integer."); |
| } else if (number == 1) { |
| return new int[] { 1 }; |
| } |
| |
| Vector factors = new Vector(); |
| int n = number; |
| |
| for (int i = 2; (i <= n) && ((i * i) <= number); i++) { |
| // It is bad practice to place log requests within tight loops. |
| // It is done here to show interleaved log output from |
| // different requests. |
| logger.debug("Trying to see if " + i + " is a factor."); |
| |
| if ((n % i) == 0) { |
| logger.info("Found factor " + i); |
| factors.addElement(new Integer(i)); |
| |
| do { |
| n /= i; |
| } while ((n % i) == 0); |
| } |
| |
| // Placing artificial delays in tight-loops will also lead to sub-optimal |
| // resuts. :-) |
| delay(100); |
| } |
| |
| if (n != 1) { |
| logger.info("Found factor " + n); |
| factors.addElement(new Integer(n)); |
| } |
| |
| int len = factors.size(); |
| |
| int[] result = new int[len]; |
| |
| for (int i = 0; i < len; i++) { |
| result[i] = ((Integer) factors.elementAt(i)).intValue(); |
| } |
| |
| // Before leaving a thread we call NDC.remove. This deletes the reference |
| // to the thread in the internal hash table. Version 0.8.5 introduces a |
| // a lazy removal mechanism in case you forget to call remove when |
| // exiting a thread. See the java documentation in NDC.remove for further |
| // details. |
| NDC.remove(); |
| |
| return result; |
| } |
| |
| static void usage(String msg) { |
| System.err.println(msg); |
| System.err.println( |
| "Usage: java org.apache.log4j.examples.NumberCruncherServer configFile\n" |
| + " where configFile is a log4j configuration file."); |
| System.exit(1); |
| } |
| |
| public static void delay(int millis) { |
| try { |
| Thread.sleep(millis); |
| } catch (InterruptedException e) { |
| } |
| } |
| |
| public static void main(String[] args) { |
| if (args.length != 1) { |
| usage("Wrong number of arguments."); |
| } |
| |
| NumberCruncherServer ncs; |
| PropertyConfigurator.configure(args[0]); |
| |
| try { |
| ncs = new NumberCruncherServer(); |
| Naming.rebind("Factor", ncs); |
| logger.info("NumberCruncherServer bound and ready to serve."); |
| } catch (Exception e) { |
| logger.error("Could not bind NumberCruncherServer.", e); |
| return; |
| } |
| NumberCruncherClient.loop(ncs); |
| } |
| } |