ByteArrayTransfer (Eclipse Rich Ajax Platform API Specification)

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Eclipse Rich Ajax Platform
Release 1.3

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org.eclipse.swt.dnd
Class ByteArrayTransfer

java.lang.Object
  org.eclipse.swt.dnd.Transfer
      org.eclipse.swt.dnd.ByteArrayTransfer

Direct Known Subclasses:: FileTransfer, HTMLTransfer, ImageTransfer, RTFTransfer, TextTransfer, URLTransfer

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.

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 subclass 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};
 }
 }

Since:: 1.3
See Also:: Transfer

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, or false otherwise (including if transferData is `null`).
`void`	`javaToNative(Object object, TransferData transferData)` This implementation of `javaToNative` converts a java `byte[]` to a platform specific representation.
`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, validate

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail