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

   1 // $Id$
   2 /**
   3 * Copyright (C) 2007 EDIT
   4 * European Distributed Institute of Taxonomy
   5 * http://www.e-taxonomy.eu
   6 *
   7 * The contents of this file are subject to the Mozilla Public License Version 1.1
   8 * See LICENSE.TXT at the top of this package for the full license terms.
   9 */
  10
  11 package eu.etaxonomy.taxeditor.model;
  12
  13 import java.io.ByteArrayInputStream;
  14 import java.io.ByteArrayOutputStream;
  15 import java.io.DataInputStream;
  16 import java.io.DataOutputStream;
  17 import java.io.EOFException;
  18 import java.io.IOException;
  19 import java.util.ArrayList;
  20 import java.util.List;
  21 import java.util.UUID;
  22
  23 import org.eclipse.swt.dnd.ByteArrayTransfer;
  24 import org.eclipse.swt.dnd.TransferData;
  25
  26 import eu.etaxonomy.cdm.model.common.ICdmBase;
  27
  28 /**
  29  * @author n.hoffmann
  30  * @created Feb 8, 2011
  31  * @version 1.0
  32  */
  33 public abstract class CdmObjectTransfer<T extends ICdmBase> extends ByteArrayTransfer {
  34
  35         /* (non-Javadoc)
  36          * @see org.eclipse.swt.dnd.ByteArrayTransfer#javaToNative(java.lang.Object, org.eclipse.swt.dnd.TransferData)
  37          */
  38         @Override
  39         protected void javaToNative(Object object, TransferData transferData) {
  40                 byte[] bytes = toByteArray((T[]) object);
  41                 if (bytes != null)
  42                         super.javaToNative(bytes, transferData);
  43         }
  44
  45         /* (non-Javadoc)
  46          * @see org.eclipse.swt.dnd.ByteArrayTransfer#nativeToJava(org.eclipse.swt.dnd.TransferData)
  47          */
  48         @Override
  49         protected Object nativeToJava(TransferData transferData) {
  50                 byte[] bytes = (byte[]) super.nativeToJava(transferData);
  51                 return fromByteArray(bytes);
  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         /**
 100          * @param in
 101          * @return
 102          * @throws IOException
 103          */
 104         public UUID readElementUuid(DataInputStream in) throws IOException{
 105                 return UUID.fromString(in.readUTF());
 106         }
 107 }