FileDriver.java

   1 package org.argeo.slc.detached.drivers;
   2
   3 import java.io.File;
   4 import java.io.FileInputStream;
   5 import java.io.FileOutputStream;
   6 import java.io.IOException;
   7 import java.io.ObjectInputStream;
   8 import java.io.ObjectOutputStream;
   9
  10 import org.apache.commons.logging.Log;
  11 import org.apache.commons.logging.LogFactory;
  12 import org.argeo.slc.detached.DetachedAnswer;
  13 import org.argeo.slc.detached.DetachedClient;
  14 import org.argeo.slc.detached.DetachedCommunication;
  15 import org.argeo.slc.detached.DetachedException;
  16 import org.argeo.slc.detached.DetachedRequest;
  17 import org.springframework.beans.factory.InitializingBean;
  18
  19 public class FileDriver extends AbstractDriver implements DetachedClient,
  20                 InitializingBean {
  21         private final static Log log = LogFactory.getLog(FileDriver.class);
  22
  23         private File baseDir;
  24         private File requestsDir;
  25         private File answersDir;
  26         private File processedRequestsDir;
  27         private File processedAnswersDir;
  28
  29         public synchronized DetachedRequest receiveRequest() throws Exception {
  30                 DetachedRequest request = (DetachedRequest) receiveFile(requestsDir,
  31                                 processedRequestsDir);
  32                 if (request != null)
  33                         log.debug("Received detached request #" + request.getUuid()
  34                                         + " for ref '" + request.getRef() + "', path="
  35                                         + request.getPath());
  36                 return request;
  37         }
  38
  39         public void sendAnswer(DetachedAnswer answer) throws Exception {
  40                 sendFile(answersDir, answer);
  41                 log.debug("Sent     detached answer  #" + answer.getUuid());
  42         }
  43
  44         public DetachedAnswer receiveAnswer() throws Exception {
  45                 DetachedAnswer answer = (DetachedAnswer) receiveFile(answersDir,
  46                                 processedAnswersDir);
  47                 if (answer != null)
  48                         log.debug("Received detached answer  #" + answer.getUuid());
  49                 return answer;
  50         }
  51
  52         public void sendRequest(DetachedRequest request) throws Exception {
  53                 sendFile(requestsDir, request);
  54                 log.debug("Sent     detached request #" + request.getUuid()
  55                                 + " for ref '" + request.getRef() + "', path="
  56                                 + request.getPath());
  57         }
  58
  59         protected void sendFile(File dir, DetachedCommunication detCom)
  60                         throws Exception {
  61                 File file = new File(dir.getPath() + File.separator + detCom.getUuid());
  62                 File lockFile = createLockFile(file);
  63                 ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(
  64                                 file));
  65                 out.writeObject(detCom);
  66                 out.close();
  67                 lockFile.delete();
  68         }
  69
  70         protected synchronized DetachedCommunication receiveFile(File dir,
  71                         File processedDir) throws Exception {
  72                 File file = null;
  73                 while (file == null && isActive()) {
  74                         if (!dir.exists())
  75                                 throw new DetachedException("Dir " + dir + " does not exist.");
  76
  77                         File[] files = dir.listFiles();
  78                         if (files.length > 0)
  79                                 file = files[0];
  80                         else {
  81                                 try {
  82                                         wait(100);
  83                                 } catch (InterruptedException e) {
  84                                         // silent
  85                                 }
  86                         }
  87                 }
  88
  89                 if (!isActive())
  90                         return null;
  91
  92                 File lockFile = nameLockFile(file);
  93                 while (lockFile.exists())
  94                         // TODO: implements time out
  95                         Thread.sleep(100);
  96
  97                 ObjectInputStream in = new ObjectInputStream(new FileInputStream(file));
  98                 DetachedCommunication detCom = (DetachedCommunication) in.readObject();
  99                 in.close();
 100
 101                 // Move to processed dir
 102                 file.renameTo(new File(processedDir.getAbsolutePath() + File.separator
 103                                 + file.getName()));
 104                 return detCom;
 105
 106         }
 107
 108         protected File createLockFile(File file) {
 109                 File lockFile = nameLockFile(file);
 110                 try {
 111                         lockFile.createNewFile();
 112                 } catch (IOException e) {
 113                         throw new DetachedException("Cannot create lock file " + lockFile);
 114                 }
 115                 return lockFile;
 116         }
 117
 118         protected File nameLockFile(File file) {
 119                 return new File(file.getAbsolutePath() + ".lck");
 120         }
 121
 122         public void setBaseDir(File baseDir) {
 123                 this.baseDir = baseDir;
 124         }
 125
 126         private void createIfNotExist(File dir) {
 127                 if (!dir.exists()) {
 128                         log.warn("Dir " + dir.getAbsolutePath()
 129                                         + " does not exist. Creating it...");
 130                         dir.mkdirs();
 131                 }
 132         }
 133
 134         public void afterPropertiesSet() throws Exception {
 135                 this.requestsDir = new File(baseDir.getAbsolutePath() + File.separator
 136                                 + "requests");
 137                 this.answersDir = new File(baseDir.getAbsolutePath() + File.separator
 138                                 + "answers");
 139                 this.processedRequestsDir = new File(baseDir.getAbsolutePath()
 140                                 + File.separator + "processed" + File.separator + "requests");
 141                 this.processedAnswersDir = new File(baseDir.getAbsolutePath()
 142                                 + File.separator + "processed" + File.separator + "answers");
 143
 144                 createIfNotExist(requestsDir);
 145                 createIfNotExist(answersDir);
 146                 createIfNotExist(processedRequestsDir);
 147                 createIfNotExist(processedAnswersDir);
 148         }
 149
 150 }