implementation, docu

Issue #135

imixs-archive-api/README.md

@@ -101,6 +101,21 @@ The synchronization between a Imixs-Archive Service and a Imixs-Workflow Instanc
 The Imixs-Archive Service polls the snapshot EventLog entries on a scheduled basis and pulls the snappshot data.
 
 
+## Overwrite File File Data
+
+The environment variable SNAPSHOT_OVERWRITEFILECONTENT can be used to protect existing file data to be overwritten. If the environment variable is set to 'false', than in case a file with the same name already exits, will be 'archived' with a time-stamp-sufix:
+
+     '<FILE_NAME>.pdf' => '<FILE_NAME>-1514410113556.pdf'
+
+This protects already archived file data and allows the 'versioning' of file content.
+
+If the environment variable SNAPSHOT_OVERWRITEFILECONTENT is not set then it default to 'false' which means existing file data is protected. 
+
+### Temporary overwriting of File Data
+
+During the processing life cycle this mechanism can be overwritten by providing the temporarily item '$snapshot.overwriteFileContent' with a list of filenames to be overwritten even if the environment variable is set to false. The item will automatically be cleared during the processing life cycle. 
+
+
 # How to Calculate the Size of a Imixs-Archive System?
 
 To calculate the size of an Imixs-Archive system, the following factors are crucial: 

imixs-archive-api/src/main/java/org/imixs/archive/core/SnapshotService.java

@@ -129,6 +129,7 @@ public class SnapshotService {
 
     public final static String ITEM_FILEDATA_FILE_NAMES = "$file.names"; // list of files
     public final static String ITEM_FILEDATA_FILE_COUNT = "$file.count"; // count of files
+    public final static String ITEM_SNAPSHOT_OVERWRITEFILECONTENT = "$snapshot.overwriteFileContent"; // force overwriting file content
 
     public static final String PROPERTY_SNAPSHOT_WORKITEMLOB_SUPPORT = "snapshot.workitemlob_suport";
     public static final String PROPERTY_SNAPSHOT_HISTORY = "snapshot.history";
@@ -319,11 +320,11 @@ public void onSave(@Observes DocumentEvent documentEvent) {
         }
 
         // 5.a. update fileData Meta information...
-        documentEvent.getDocument().replaceItemValue(ITEM_FILEDATA_FILE_COUNT,
-                documentEvent.getDocument().getFileNames().size());
-        documentEvent.getDocument().replaceItemValue(ITEM_FILEDATA_FILE_NAMES,
-                documentEvent.getDocument().getFileNames());
         // TODO : $file.count and $file.names is computed by ItemCollection and can be removed from here.
+//        documentEvent.getDocument().replaceItemValue(ITEM_FILEDATA_FILE_COUNT,
+//                documentEvent.getDocument().getFileNames().size());
+//        documentEvent.getDocument().replaceItemValue(ITEM_FILEDATA_FILE_NAMES,
+//                documentEvent.getDocument().getFileNames());
 
         // 6. store the snapshot uniqeId into the origin-workitem ($snapshotID)
         documentEvent.getDocument().replaceItemValue(SNAPSHOTID, snapshot.getUniqueID());
@@ -523,6 +524,8 @@ private void copyFilesFromItemCollection(ItemCollection source, ItemCollection t
         boolean debug = logger.isLoggable(Level.FINE);
 
         List<FileData> files = target.getFileData();
+
+        List<String> overwriteFileList=origin.getItemValueList(ITEM_SNAPSHOT_OVERWRITEFILECONTENT, String.class);
 
         for (FileData fileData : files) {
             String fileName = fileData.getName();
@@ -558,7 +561,10 @@ private void copyFilesFromItemCollection(ItemCollection source, ItemCollection t
                 // in case 'overwriteFileContent' is set to 'false' we protect existing content
                 // of
                 // files with the same name, but extend the name of the old file with a suffix
-                if (!overwriteFileContent) {
+                // This feature can be skiped if $snapshot.overwriteFileContent contans the filename
+
+
+                if (!overwriteFileContent && !(overwriteFileList.contains(fileName))) {
                     FileData oldFileData = source.getFileData(fileName);
                     if (oldFileData != null) {
                         // we need to suffix the last file with the same name here to protect the
@@ -610,6 +616,9 @@ private void copyFilesFromItemCollection(ItemCollection source, ItemCollection t
                 }
             }
         }
+
+        // clean "$snapshot.overwriteFileContent"
+        origin.replaceItemValue(ITEM_SNAPSHOT_OVERWRITEFILECONTENT, "");
 
     }