/*
 * @(#)StringSelection.java	1.21 03/12/19
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.awt.datatransfer;

import java.io.*;

/**
 * A <code>Transferable</code> which implements the capability required
 * to transfer a <code>String</code>.
 *
 * This <code>Transferable</code> properly supports
 * <code>DataFlavor.stringFlavor</code>
 * and all equivalent flavors. Support for
 * <code>DataFlavor.plainTextFlavor</code>
 * and all equivalent flavors is <b>deprecated</b>. No other
 * <code>DataFlavor</code>s are supported.
 *
 * @see java.awt.datatransfer.DataFlavor#stringFlavor
 * @see java.awt.datatransfer.DataFlavor#plainTextFlavor
 */
public class StringSelection implements Transferable, ClipboardOwner {

    private static final int STRING = 0;
    private static final int PLAIN_TEXT = 1;

    private static final DataFlavor[] flavors = {
        DataFlavor.stringFlavor,
	DataFlavor.plainTextFlavor // deprecated
    };

    private String data;
						   
    /**
     * Creates a <code>Transferable</code> capable of transferring
     * the specified <code>String</code>.
     */
    public StringSelection(String data) {
        this.data = data;
    }

    /**
     * Returns an array of flavors in which this <code>Transferable</code>
     * can provide the data. <code>DataFlavor.stringFlavor</code>
     * is properly supported.
     * Support for <code>DataFlavor.plainTextFlavor</code> is
     * <b>deprecated</b>.
     *
     * @return an array of length two, whose elements are <code>DataFlavor.
     *         stringFlavor</code> and <code>DataFlavor.plainTextFlavor</code>
     */
    public DataFlavor[] getTransferDataFlavors() {
        // returning flavors itself would allow client code to modify
        // our internal behavior
	return (DataFlavor[])flavors.clone();
    }

    /**
     * Returns whether the requested flavor is supported by this
     * <code>Transferable</code>.
     *
     * @param flavor the requested flavor for the data
     * @return true if <code>flavor</code> is equal to
     *   <code>DataFlavor.stringFlavor</code> or
     *   <code>DataFlavor.plainTextFlavor</code>; false if <code>flavor</code>
     *   is not one of the above flavors
     * @throws NullPointerException if flavor is <code>null</code>
     */
    public boolean isDataFlavorSupported(DataFlavor flavor) {
	// JCK Test StringSelection0003: if 'flavor' is null, throw NPE
        for (int i = 0; i < flavors.length; i++) {
	    if (flavor.equals(flavors[i])) {
	        return true;
	    }
	}
	return false;
    }

    /**
     * Returns the <code>Transferable</code>'s data in the requested
     * <code>DataFlavor</code> if possible. If the desired flavor is
     * <code>DataFlavor.stringFlavor</code>, or an equivalent flavor,
     * the <code>String</code> representing the selection is
     * returned. If the desired flavor is
     * <code>DataFlavor.plainTextFlavor</code>,
     * or an equivalent flavor, a <code>Reader</code> is returned.
     * <b>Note:</b> The behavior of this method for
     * </code>DataFlavor.plainTextFlavor</code>
     * and equivalent <code>DataFlavor</code>s is inconsistent with the
     * definition of <code>DataFlavor.plainTextFlavor</code>.
     *
     * @param flavor the requested flavor for the data
     * @return the data in the requested flavor, as outlined above
     * @throws UnsupportedFlavorException if the requested data flavor is
     *         not equivalent to either <code>DataFlavor.stringFlavor</code>
     *         or <code>DataFlavor.plainTextFlavor</code>
     * @throws IOException if an IOException occurs while retrieving the data.
     *         By default, StringSelection never throws this exception, but a
     *         subclass may.
     * @throws NullPointerException if flavor is <code>null</code>
     * @see java.io.Reader
     */
    public Object getTransferData(DataFlavor flavor)
        throws UnsupportedFlavorException, IOException
    {
	// JCK Test StringSelection0007: if 'flavor' is null, throw NPE
	if (flavor.equals(flavors[STRING])) {
	    return (Object)data;
	} else if (flavor.equals(flavors[PLAIN_TEXT])) {
	    return new StringReader(data == null ? "" : data);
	} else {
	    throw new UnsupportedFlavorException(flavor);
	}
    }

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