plugins/org.eclipse.wst.sse.sieditor.ui/api/org/eclipse/wst/sse/sieditor/ui/v2/dnd/SiEditorTransfer.java

package org.eclipse.wst.sse.sieditor.ui.v2.dnd;

import java.nio.charset.Charset;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.util.Policy;
import org.eclipse.swt.dnd.ByteArrayTransfer;
import org.eclipse.swt.dnd.TransferData;
import org.eclipse.wst.sse.sieditor.model.api.INamedObject;

/**
 * Class for serializing gadgets to/from a byte array
 */
public class SiEditorTransfer extends ByteArrayTransfer {
    private static SiEditorTransfer instance = new SiEditorTransfer();
    private static final String TYPE_NAME = "sie-transfer-format"; //$NON-NLS-1$
    private static final int TYPEID = registerType(TYPE_NAME);

    private INamedObject modelObject;

    public static SiEditorTransfer getInstance() {
        return instance;
    }

    private SiEditorTransfer() {
    }

    protected int[] getTypeIds() {
        return new int[] { TYPEID };
    }

    /*
     * Method declared on Transfer.
     */
    protected String[] getTypeNames() {
        return new String[] { TYPE_NAME };
    }

    @Override
    public boolean isSupportedType(TransferData transferData) {
        return transferData.type == TYPEID;
    }

    private boolean isInvalidNativeType(Object result) {
        return !(result instanceof byte[]) || !TYPE_NAME.equals(new String((byte[]) result, Charset.forName("UTF-8"))); //$NON-NLS-1$
    }

    public void javaToNative(Object object, TransferData transferData) {
        byte[] check = TYPE_NAME.getBytes(Charset.forName("UTF-8")); //$NON-NLS-1$
        super.javaToNative(check, transferData);
        modelObject = (INamedObject) object;
    }

    public Object nativeToJava(TransferData transferData) {
        Object result = super.nativeToJava(transferData);
        if (isInvalidNativeType(result)) {
            Policy.getLog().log(
                    new Status(IStatus.ERROR, Policy.JFACE, IStatus.ERROR, JFaceResources
                            .getString("LocalContextSelectionTransfer.errorMessage"), null)); //$NON-NLS-1$
        }
        return modelObject;
    }

}