org.eclipse.swt.dnd
Class ByteArrayTransfer

java.lang.Object
  |
  +--org.eclipse.swt.dnd.Transfer
        |
        +--org.eclipse.swt.dnd.ByteArrayTransfer

Direct Known Subclasses:

FileTransfer, MarkerTransfer, PluginTransfer, ResourceTransfer, RTFTransfer, TextTransfer

public abstract class ByteArrayTransfer

extends Transfer

The class ByteArrayTransfer provides a platform specific mechanism for converting a java byte[] to a platform specific representation of the byte array and vice versa. See Transfer for additional information.

ByteArrayTransfer is never used directly but is sub-classed by transfer agents that convert between data in a java format such as a String and a platform specific byte array.

If the data you are converting does not map to a byte[], you should sub-class Transfer directly and do your own mapping to a platform data type.

The following snippet shows a sublcass of ByteArrayTransfer that transfers data defined by the class MyType.

 public class MyType {
	public String fileName;
	public long fileLength;
	public long lastModified;
 }
 

 public class MyTypeTransfer extends ByteArrayTransfer {
	
	private static final String MYTYPENAME = "my_type_name";
	private static final int MYTYPEID = registerType(MYTYPENAME);
	private static MyTypeTransfer _instance = new MyTypeTransfer();
 
 private MyTypeTransfer() {}
 
 public static MyTypeTransfer getInstance () {
 	return _instance;
 }
 public void javaToNative (Object object, TransferData transferData) {
 	if (object == null || !(object instanceof MyType[])) return;
 	
 	if (isSupportedType(transferData)) {
 		MyType[] myTypes = (MyType[]) object;	
 		try {
 			// write data to a byte array and then ask super to convert to pMedium
 			ByteArrayOutputStream out = new ByteArrayOutputStream();
 			DataOutputStream writeOut = new DataOutputStream(out);
 			for (int i = 0, length = myTypes.length; i < length;  i++){
 				byte[] buffer = myTypes[i].fileName.getBytes();
 				writeOut.writeInt(buffer.length);
 				writeOut.write(buffer);
 				writeOut.writeLong(myTypes[i].fileLength);
 				writeOut.writeLong(myTypes[i].lastModified);
 			}
 			byte[] buffer = out.toByteArray();
 			writeOut.close();
 
 			super.javaToNative(buffer, transferData);
 			
 		} catch (IOException e) {
 		}
 	}
 }
 public Object nativeToJava(TransferData transferData){	
 
 	if (isSupportedType(transferData)) {
 		
 		byte[] buffer = (byte[])super.nativeToJava(transferData);
 		if (buffer == null) return null;
 		
 		MyType[] myData = new MyType[0];
 		try {
 			ByteArrayInputStream in = new ByteArrayInputStream(buffer);
 			DataInputStream readIn = new DataInputStream(in);
 			while(readIn.available() > 20) {
 				MyType datum = new MyType();
 				int size = readIn.readInt();
 				byte[] name = new byte[size];
 				readIn.read(name);
 				datum.fileName = new String(name);
 				datum.fileLength = readIn.readLong();
 				datum.lastModified = readIn.readLong();
 				MyType[] newMyData = new MyType[myData.length + 1];
 				System.arraycopy(myData, 0, newMyData, 0, myData.length);
 				newMyData[myData.length] = datum;
 				myData = newMyData;
 			}
 			readIn.close();
 		} catch (IOException ex) {
 			return null;
 		}
 		return myData;
 	}
 
 	return null;
 }
 protected String[] getTypeNames(){
 	return new String[]{MYTYPENAME};
 }
 protected int[] getTypeIds(){
 	return new int[] {MYTYPEID};
 }
 }















Constructor Summary
ByteArrayTransfer()



           
 



Method Summary




 TransferData[]
getSupportedTypes()



          Returns a list of the platform specific data types that can be converted using 
 this transfer agent.



 boolean
isSupportedType(TransferData transferData)



          Returns true if the TransferData data type can be converted 
 using this transfer agent.



protected  void
javaToNative(Object object,
             TransferData transferData)



          This implementation of javaToNative converts a java 
 byte[] to a platform specific representation.



protected  Object
nativeToJava(TransferData transferData)



          This implementation of nativeToJava converts a platform specific 
 representation of a byte array to a java byte[].


 
Methods inherited from class org.eclipse.swt.dnd.Transfer
getTypeIds, getTypeNames, registerType
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 








Constructor Detail



ByteArrayTransfer
public ByteArrayTransfer()






Method Detail



getSupportedTypes
public TransferData[] getSupportedTypes()

Description copied from class: Transfer
Returns a list of the platform specific data types that can be converted using 
 this transfer agent.

 
Only the data type fields of the TransferData objects are filled 
 in.


Specified by:
getSupportedTypes in class Transfer



Returns:
a list of the data types that can be converted using this transfer agent





isSupportedType
public boolean isSupportedType(TransferData transferData)

Description copied from class: Transfer
Returns true if the TransferData data type can be converted 
 using this transfer agent.


Specified by:
isSupportedType in class Transfer


Parameters:
transferData - a platform specific description of a data type; only the data
  type fields of the TransferData object need to be filled in
Returns:
true if the transferData data type can be converted using this transfer 
 agent





javaToNative
protected void javaToNative(Object object,
                            TransferData transferData)

This implementation of javaToNative converts a java 
 byte[] to a platform specific representation.  For additional
 information see Transfer#javaToNative.


Specified by:
javaToNative in class Transfer


Parameters:
object - a java byte[] containing the data to be converted
transferData - an empty TransferData object; this
  object will be filled in on return with the platform specific format of the data
See Also:
Transfer.javaToNative(java.lang.Object, org.eclipse.swt.dnd.TransferData)





nativeToJava
protected Object nativeToJava(TransferData transferData)

This implementation of nativeToJava converts a platform specific 
 representation of a byte array to a java byte[].   
 For additional information see Transfer#nativeToJava.


Specified by:
nativeToJava in class Transfer


Parameters:
transferData - the platform specific representation of the data to be 
 been converted
Returns:
a java byte[] containing the converted data if the 
 conversion was successful; otherwise null
See Also:
Transfer.nativeToJava(org.eclipse.swt.dnd.TransferData)