eu.etaxonomy.taxeditor.store/src/main/java/eu/etaxonomy/taxeditor/model/CdmObjectTransfer.java

   1 /**
   2 * Copyright (C) 2007 EDIT
   3 * European Distributed Institute of Taxonomy
   4 * http://www.e-taxonomy.eu
   5 *
   6 * The contents of this file are subject to the Mozilla Public License Version 1.1
   7 * See LICENSE.TXT at the top of this package for the full license terms.
   8 */
   9
  10 package eu.etaxonomy.taxeditor.model;
  11
  12 import java.io.ByteArrayInputStream;
  13 import java.io.ByteArrayOutputStream;
  14 import java.io.DataInputStream;
  15 import java.io.DataOutputStream;
  16 import java.io.EOFException;
  17 import java.io.IOException;
  18 import java.util.ArrayList;
  19 import java.util.List;
  20 import java.util.UUID;
  21
  22 import org.eclipse.swt.dnd.ByteArrayTransfer;
  23 import org.eclipse.swt.dnd.TransferData;
  24
  25 import eu.etaxonomy.cdm.model.common.ICdmBase;
  26
  27 /**
  28  * @author n.hoffmann
  29  * @created Feb 8, 2011
  30  * @version 1.0
  31  */
  32 public abstract class CdmObjectTransfer<T extends ICdmBase> extends ByteArrayTransfer {
  33
  34         @Override
  35         protected void javaToNative(Object object, TransferData transferData) {
  36                 if (object != null){
  37                         byte[] bytes = toByteArray((T[]) object);
  38                         if (bytes != null) {
  39                 super.javaToNative(bytes, transferData);
  40             }
  41                 }
  42         }
  43
  44         @Override
  45         protected Object nativeToJava(TransferData transferData) {
  46                 byte[] bytes = (byte[]) super.nativeToJava(transferData);
  47                 if (bytes != null){
  48                         return fromByteArray(bytes);
  49                 }
  50                 return null;
  51         }
  52
  53
  54         protected byte[] toByteArray(T[] elements) {
  55                 ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
  56                 DataOutputStream out = new DataOutputStream(byteOut);
  57
  58                 byte[] bytes = null;
  59
  60                 try {
  61
  62                         for(T element : elements){
  63                                 writeElementUuid(element, out);
  64                         }
  65                         out.close();
  66                         bytes = byteOut.toByteArray();
  67                 } catch (IOException e) {
  68                         // when in doubt send nothing
  69                 }
  70                 return bytes;
  71         }
  72
  73         private void writeElementUuid(T element, DataOutputStream out) throws IOException {
  74                 out.writeUTF(element.getUuid().toString());
  75         }
  76
  77         protected Object fromByteArray(byte[] bytes) {
  78                 DataInputStream in = new DataInputStream(
  79                                 new ByteArrayInputStream(bytes));
  80
  81                 try {
  82                         List<T> elements = new ArrayList<T>();
  83
  84                         try{
  85                                 while(true){
  86                                         UUID uuid = readElementUuid(in);
  87                                         elements.add(loadElement(uuid));
  88                                 }
  89                         }catch(EOFException e){
  90                                 return elements.toArray();
  91                         }
  92                 } catch (IOException e) {
  93                         return null;
  94                 }
  95         }
  96
  97         public abstract T loadElement(UUID uuid);
  98
  99         public UUID readElementUuid(DataInputStream in) throws IOException{
 100                 return UUID.fromString(in.readUTF());
 101         }
 102 }