--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/dnd/Transfer.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,154 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2007 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+module dwt.dnd;
+
+ 
+/**
+ * <code>Transfer</code> provides a mechanism for converting between a java 
+ * representation of data and a platform specific representation of data and 
+ * vice versa.  It is used in data transfer operations such as drag and drop and 
+ * clipboard copy/paste.
+ *
+ * <p>You should only need to become familiar with this class if you are 
+ * implementing a Transfer subclass and you are unable to subclass the 
+ * ByteArrayTransfer class.</p>
+ * 
+ * @see ByteArrayTransfer
+ */
+public abstract class Transfer {
+    
+/**
+ * Returns a list of the platform specific data types that can be converted using 
+ * this transfer agent.
+ *
+ * <p>Only the data type fields of the <code>TransferData</code> objects are filled 
+ * in.</p>
+ *
+ * @return a list of the data types that can be converted using this transfer agent
+ */
+abstract public TransferData[] getSupportedTypes();
+
+/**
+ * Returns true if the <code>TransferData</code> data type can be converted 
+ * using this transfer agent, or false otherwise (including if transferData is
+ * <code>null</code>).
+ *
+ * @param transferData a platform specific description of a data type; only the data
+ *  type fields of the <code>TransferData</code> object need to be filled in
+ *
+ * @return true if the transferData data type can be converted using this transfer 
+ * agent
+ */
+abstract public bool isSupportedType(TransferData transferData);
+
+/**
+ * Returns the platform specific ids of the  data types that can be converted using 
+ * this transfer agent.
+ * 
+ * @return the platform specific ids of the data types that can be converted using 
+ * this transfer agent
+ */
+abstract protected int[] getTypeIds();
+
+/**
+ * Returns the platform specific names of the  data types that can be converted 
+ * using this transfer agent.
+ * 
+ * @return the platform specific names of the data types that can be converted 
+ * using this transfer agent.
+ */
+abstract protected String[] getTypeNames();
+
+/**
+ * Converts a java representation of data to a platform specific representation of 
+ * the data. 
+ *
+ * <p>On a successful conversion, the transferData.result field will be set as follows:
+ * <ul>
+ * <li>Windows: COM.S_OK
+ * <li>Motif: 1
+ * <li>GTK: 1
+ * <li>Photon: 1
+ * </ul></p>
+ * 
+ * <p>If this transfer agent is unable to perform the conversion, the transferData.result 
+ * field will be set to a failure value as follows:
+ * <ul>
+ * <li>Windows: COM.DV_E_TYMED or COM.E_FAIL
+ * <li>Motif: 0
+ * <li>GTK: 0
+ * <li>Photon: 0
+ * </ul></p>
+ *
+ * @param object a java representation of the data to be converted; the type of
+ * Object that is passed in is dependent on the <code>Transfer</code> subclass.
+ *
+ * @param transferData an empty TransferData object; this object will be 
+ * filled in on return with the platform specific representation of the data
+ * 
+ * @exception dwt.DWTException <ul>
+ *    <li>ERROR_INVALID_DATA - if object does not contain data in a valid format or is <code>null</code></li>
+ * </ul>
+ */
+abstract protected void javaToNative (Object object, TransferData transferData);
+
+/**
+ * Converts a platform specific representation of data to a java representation.
+ * 
+ * @param transferData the platform specific representation of the data to be 
+ * converted
+ *
+ * @return a java representation of the converted data if the conversion was 
+ * successful; otherwise null.  If transferData is <code>null</code> then
+ * <code>null</code> is returned.  The type of Object that is returned is 
+ * dependent on the <code>Transfer</code> subclass.
+ */
+abstract protected Object nativeToJava(TransferData transferData);
+
+/**
+ * Registers a name for a data type and returns the associated unique identifier.
+ *
+ * <p>You may register the same type more than once, the same unique identifier 
+ * will be returned if the type has been previously registered.</p>
+ *
+ * <p>Note: On windows, do <b>not</b> call this method with pre-defined 
+ * Clipboard Format types such as CF_TEXT or CF_BITMAP because the 
+ * pre-defined identifier will not be returned</p>
+ *
+ * @param formatName the name of a data type
+ *
+ * @return the unique identifier associated with this data type
+ */
+public static int registerType(String formatName) {
+    int length = formatName.length();
+    // TODO - hashcode may not be unique - need another way
+    if (length > 4) return formatName.toHash();
+    int type = 0;
+    if (length > 0) type |= (formatName.charAt(0) & 0xff) << 24;
+    if (length > 1) type |= (formatName.charAt(1) & 0xff) << 16;
+    if (length > 2) type |= (formatName.charAt(2) & 0xff) << 8;
+    if (length > 3) type |= formatName.charAt(3) & 0xff; 
+    return type;
+}
+
+/**
+ * Test that the object is of the correct format for this Transfer class.
+ * 
+ * @param object a java representation of the data to be converted
+ * 
+ * @return true if object is of the correct form for this transfer type
+ * 
+ * @since 3.1
+ */
+protected bool validate(Object object) {
+    return true;
+}
+}