Name: bb33257 Date: 02/05/99


Only the StringSelection class can transfer text to other
applications using the Windows clipboard (visible to other
applications) on NT. Any content which supports the plain text
or string data flavor should be able to transfer character data
to other apps with the Windows clipboard.

It appears the system clipboard doesn't check the available
flavors, and instead does an instanceof check to decide when to
transfer text to the Windows clipboard.

The following program has a duplicate StringSelection class. It
cannot transfer character data to the Windows clipboard on 1.1.7a:

import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.ClipboardOwner;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.UnsupportedFlavorException;

import java.awt.Toolkit;
import java.io.*;

public class TestSystemClipboard {

    public static void main(String[] args) {

        String str = "This string should be on the system clipboard.";
        Clipboard sysClip = Toolkit.getDefaultToolkit().getSystemClipboard();
        MyStringSelection selection = new MyStringSelection(str);
        sysClip.setContents(selection, selection);

        // Can't test without looking at Windows clipboard viewer.
        // The test passes if the above string is on the clipboard.
        System.out.println("Look at the Clipboard Viewer, and see if the "+
                           "following string is the clipboard contents:");
        System.out.println(str);
    }

/*
 * This is a copy of the StringSelection class, which has been renamed.
 */
    private static class MyStringSelection implements Transferable, ClipboardOwner{
    final int STRING = 0;
    final int PLAIN_TEXT = 1;

    DataFlavor flavors[] = {DataFlavor.stringFlavor, DataFlavor.plainTextFlavor};

    private String data;

    /**
     * Creates a transferable object capable of transferring the
     * specified string in plain text format.
     */
    public MyStringSelection(String data) {
        this.data = data;
    }

    /**
     * Returns the array of flavors in which it can provide the data.
     */
    public synchronized DataFlavor[] getTransferDataFlavors() {
return flavors;
    }

    /**
     * Returns whether the requested flavor is supported by this object.
     * @param flavor the requested flavor for the data
     */
    public boolean isDataFlavorSupported(DataFlavor flavor) {
return (flavor.equals(flavors[STRING]) || flavor.equals(flavors[PLAIN_TEXT]));
    }

    /**
     * If the data was requested in the "java.lang.String" flavor, return the
     * String representing the selection.
     *
     * @param flavor the requested flavor for the data
     * @exception UnsupportedFlavorException if the requested data flavor is
     * not supported in the "<code>java.lang.String</code>" flavor.
     */
    public synchronized Object getTransferData(DataFlavor flavor)
throws UnsupportedFlavorException, IOException {
if (flavor.equals(flavors[STRING])) {
return (Object)data;
} else if (flavor.equals(flavors[PLAIN_TEXT])) {
return new StringReader(data);
} else {
throw new UnsupportedFlavorException(flavor);
}
    }

    public void lostOwnership(Clipboard clipboard, Transferable contents) {
    }
    }
}


(Review ID: 53825)

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