add method to remove oldestCrashlogs. add CrashlogsFileFilter with unitTest class.

app/src/main/java/foundation/e/drive/fileFilters/CrashlogsFileFilter.java

+package foundation.e.drive.fileFilters;
+
+import java.io.File;
+import java.io.FileFilter;
+
+import foundation.e.drive.utils.ServiceExceptionHandler;
+
+public class CrashlogsFileFilter implements FileFilter {
+    private final static long max_timestamp_delta = 864000000; //10 days in ms (240*3600*1000)
+
+    @Override
+    public boolean accept(File pathname) {
+        String fileTimestamp = extractTimestamp(pathname.getName(),
+                ServiceExceptionHandler.LOG_FILE_NAME_PREFIX,
+                ServiceExceptionHandler.LOG_FILE_EXTENSION);
+
+        long timestamp;
+        try {
+            timestamp = Long.parseLong(fileTimestamp);
+        }catch (NumberFormatException e){
+            //Can't parse the extracted timestamp
+            //This file has not the expected name. It must be removed
+            return true;
+        }
+
+        //if current Date - file date >= max deta allowed
+        return ((System.currentTimeMillis() - timestamp ) >= max_timestamp_delta);
+    }
+
+    /**
+     * Extract the timestamp from the name of the file
+     * UnitTested!
+     * @param fileName Filename
+     * @param prefix prefix to ignore
+     * @param extension extension to ignore
+     * @return the timestamp extracted from the name
+     */
+    private String extractTimestamp(String fileName, String prefix, String extension){
+        return fileName.substring(prefix.length(), (fileName.length() - extension.length()));
+    }
+
+}

app/src/main/java/foundation/e/drive/services/ObserverService.java

@@ -30,13 +30,17 @@ import com.owncloud.android.lib.resources.files.model.RemoteFile;
 import java.io.File;
 import java.io.FileFilter;
 import java.io.FileOutputStream;
+import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
+import java.util.stream.Stream;
 
 import foundation.e.drive.database.DbHelper;
+import foundation.e.drive.fileFilters.CrashlogsFileFilter;
 import foundation.e.drive.fileFilters.FileFilterFactory;
 import foundation.e.drive.fileFilters.OnlyFileFilter;
 import foundation.e.drive.models.SyncedFolder;
@@ -151,12 +155,36 @@ public class ObserverService extends Service implements OnRemoteOperationListene
         Log.i(TAG, "begin()");
         this.isWorking = true;
         clearCachedFile();
+        deleteOldestCrashlogs();
         startScan(true);
     }
 
+    /**
+     * This method remove all the crash-logs file
+     * in external dir that are 10 days or more old.
+     */
+    private void deleteOldestCrashlogs(){
+        Log.i(TAG, "deleteOldestCrashLogs()");
+        File[] fileToRemove = getExternalFilesDir(ServiceExceptionHandler.CRASH_LOG_FOLDER)
+                .listFiles(new CrashlogsFileFilter());
+
+        int counter = 0;
+        for (File file : fileToRemove) {
+            try {
+                file.delete();
+                ++counter;
+            }catch (SecurityException e){
+                e.printStackTrace();
+            }
+        }
+        Log.d(TAG, counter+" old crashlogs file.s deleted");
+    }
+
+
     /**
      * Clear cached file unused:
      * remove each cached file which isn't in OperationManagerService.lockedSyncedFileState();
+     * @TODO rewrite this method!
      */
     private void clearCachedFile(){
         Log.i(TAG, "clearCachedFile()");

app/src/main/java/foundation/e/drive/utils/ServiceExceptionHandler.java

@@ -26,6 +26,9 @@ import foundation.e.drive.services.OperationManagerService;
  */
 public class ServiceExceptionHandler implements UncaughtExceptionHandler{
     private final static String TAG = ServiceExceptionHandler.class.getSimpleName();
+    public final static String CRASH_LOG_FOLDER = "crash-logs";
+    public final static String LOG_FILE_NAME_PREFIX = "eDrive-crash-";
+    public final static String LOG_FILE_EXTENSION = ".log";
     private UncaughtExceptionHandler defaultUEH;
     private Service service;
 
@@ -58,9 +61,9 @@ public class ServiceExceptionHandler implements UncaughtExceptionHandler{
             Long timestamp = System.currentTimeMillis();
 
             //Create a new file that user can sent to us
-            String fileName = "eDrive-crash-"+timestamp+".log";
+            String fileName = LOG_FILE_NAME_PREFIX+timestamp+LOG_FILE_EXTENSION;
 
-            File downloadDir = service.getApplication().getExternalFilesDir("Logs");
+            File downloadDir = service.getApplication().getExternalFilesDir(CRASH_LOG_FOLDER);
             File logFile = new File(downloadDir, fileName);
             try {
 

app/src/test/java/foundation/e/drive/Test/FileFilterTest/CrashlogFileFilterTest.java

+package foundation.e.drive.Test.FileFilterTest;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class CrashlogFileFilterTest {
+
+    private String mockFileName(String target, String prefix, String extension){
+        return prefix+target+extension;
+    }
+
+    private String extractTimestamp(String fileName, String prefix, String extension){
+        return fileName.substring(prefix.length(), (fileName.length() - extension.length()));
+    }
+
+    @Test
+    public void extractTimeStampFromFileNameTest(){
+        String prefix = "edrive-";
+        String extension = ".log";
+        String target = "";
+        //Case 1 Empty Target
+        String base = mockFileName(target, prefix, extension);
+        Assert.assertEquals("Base length is incorrect", prefix.length()+extension.length(), base.length());
+
+        String fileTimestamp = extractTimestamp(base, prefix, extension);
+        Assert.assertEquals("result is not empty String", "", fileTimestamp);
+
+        //Case 2: Prefix is empty
+        prefix = "";
+        target = "1234";
+        base = mockFileName(target, prefix, extension);
+        Assert.assertEquals("Base length is incorrect", prefix.length()+target.length()+extension.length(), base.length());
+
+        fileTimestamp = extractTimestamp(base, prefix, extension);
+        Assert.assertEquals("result is not empty String", target, fileTimestamp);
+
+        //Case 3: extension is empty
+
+        prefix = "edrive-";
+        extension = "";
+
+        base = mockFileName(target, prefix, extension);
+        Assert.assertEquals("Base length is incorrect", prefix.length()+target.length(), base.length());
+
+        fileTimestamp = extractTimestamp(base, prefix, extension);
+        Assert.assertEquals("result is not empty String", target, fileTimestamp);
+    }
+}