swingx-master/swingx-core/src/main/java/org/jdesktop/swingx/plaf/basic/core/BasicTransferable.java
/*
 * $Id$
 *
 * Copyright 2009 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
package org.jdesktop.swingx.plaf.basic.core;


import java.io.*;
import java.awt.datatransfer.*;
import javax.swing.plaf.UIResource;

/**
 * A transferable implementation for the default data transfer of some Swing
 * components.  
 *
 * @author  Timothy Prinzing
 * @version 1.10 11/17/05
 */
public class BasicTransferable implements Transferable, UIResource {
    
    protected String plainData;
    protected String htmlData;

    private static DataFlavor[] htmlFlavors;
    private static DataFlavor[] stringFlavors;
    private static DataFlavor[] plainFlavors;

    static {
        try {
            htmlFlavors = new DataFlavor[3];
            htmlFlavors[0] = new DataFlavor("text/html;class=java.lang.String");
            htmlFlavors[1] = new DataFlavor("text/html;class=java.io.Reader");
            htmlFlavors[2] = new DataFlavor("text/html;charset=unicode;class=java.io.InputStream");

            plainFlavors = new DataFlavor[3];
            plainFlavors[0] = new DataFlavor("text/plain;class=java.lang.String");
            plainFlavors[1] = new DataFlavor("text/plain;class=java.io.Reader");
            plainFlavors[2] = new DataFlavor("text/plain;charset=unicode;class=java.io.InputStream");

            stringFlavors = new DataFlavor[2];
            stringFlavors[0] = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType+";class=java.lang.String");
            stringFlavors[1] = DataFlavor.stringFlavor;
 
        } catch (ClassNotFoundException cle) {
            System.err.println("error initializing javax.swing.plaf.basic.BasicTranserable");
        }
    }
    
    public BasicTransferable(String plainData, String htmlData) {
        this.plainData = plainData;
        this.htmlData = htmlData;
    }


    /**
     * Returns an array of DataFlavor objects indicating the flavors the data 
     * can be provided in.  The array should be ordered according to preference
     * for providing the data (from most richly descriptive to least descriptive).
     * @return an array of data flavors in which this data can be transferred
     */
    public DataFlavor[] getTransferDataFlavors() {
        DataFlavor[] richerFlavors = getRicherFlavors();
        int nRicher = (richerFlavors != null) ? richerFlavors.length : 0;
        int nHTML = (isHTMLSupported()) ? htmlFlavors.length : 0;
        int nPlain = (isPlainSupported()) ? plainFlavors.length: 0;
        int nString = (isPlainSupported()) ? stringFlavors.length : 0;
        int nFlavors = nRicher + nHTML + nPlain + nString;
        DataFlavor[] flavors = new DataFlavor[nFlavors];
        
        // fill in the array
        int nDone = 0;
        if (nRicher > 0) {
            System.arraycopy(richerFlavors, 0, flavors, nDone, nRicher);
            nDone += nRicher;
        }
        if (nHTML > 0) {
            System.arraycopy(htmlFlavors, 0, flavors, nDone, nHTML);
            nDone += nHTML;
        }
        if (nPlain > 0) {
            System.arraycopy(plainFlavors, 0, flavors, nDone, nPlain);
            nDone += nPlain;
        }
        if (nString > 0) {
            System.arraycopy(stringFlavors, 0, flavors, nDone, nString);
            nDone += nString;
        }
        return flavors;
    }

    /**
     * Returns whether or not the specified data flavor is supported for
     * this object.
     * @param flavor the requested flavor for the data
     * @return boolean indicating whether or not the data flavor is supported
     */
    public boolean isDataFlavorSupported(DataFlavor flavor) {
        DataFlavor[] flavors = getTransferDataFlavors();
        for (int i = 0; i < flavors.length; i++) {
            if (flavors[i].equals(flavor)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Returns an object which represents the data to be transferred.  The class 
     * of the object returned is defined by the representation class of the flavor.
     *
     * @param flavor the requested flavor for the data
     * @see DataFlavor#getRepresentationClass
     * @exception IOException                if the data is no longer available
     *              in the requested flavor.
     * @exception UnsupportedFlavorException if the requested data flavor is
     *              not supported.
     */
    public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
        DataFlavor[] richerFlavors = getRicherFlavors();
        if (isRicherFlavor(flavor)) {
            return getRicherData(flavor);
        } else if (isHTMLFlavor(flavor)) {
            String data = getHTMLData();
            data = (data == null) ? "" : data;
            if (String.class.equals(flavor.getRepresentationClass())) {
                return data;
            } else if (Reader.class.equals(flavor.getRepresentationClass())) {
                return new StringReader(data);
            } else if (InputStream.class.equals(flavor.getRepresentationClass())) {
                return new StringBufferInputStream(data);
            }
            // fall through to unsupported
        } else if (isPlainFlavor(flavor)) {
            String data = getPlainData();
            data = (data == null) ? "" : data;
            if (String.class.equals(flavor.getRepresentationClass())) {
                return data;
            } else if (Reader.class.equals(flavor.getRepresentationClass())) {
                return new StringReader(data);
            } else if (InputStream.class.equals(flavor.getRepresentationClass())) {
                return new StringBufferInputStream(data);
            }
            // fall through to unsupported

        } else if (isStringFlavor(flavor)) {
            String data = getPlainData();
            data = (data == null) ? "" : data;
            return data;
        }
        throw new UnsupportedFlavorException(flavor);
    }

    // --- richer subclass flavors ----------------------------------------------

    protected boolean isRicherFlavor(DataFlavor flavor) {
        DataFlavor[] richerFlavors = getRicherFlavors();
        int nFlavors = (richerFlavors != null) ? richerFlavors.length : 0;
        for (int i = 0; i < nFlavors; i++) {
            if (richerFlavors[i].equals(flavor)) {
                return true;
            }
        }
        return false;
    }
        
    /** 
     * Some subclasses will have flavors that are more descriptive than HTML
     * or plain text.  If this method returns a non-null value, it will be
     * placed at the start of the array of supported flavors.
     */
    protected DataFlavor[] getRicherFlavors() {
        return null;
    }

    protected Object getRicherData(DataFlavor flavor) throws UnsupportedFlavorException {
        return null;
    }

    // --- html flavors ----------------------------------------------------------

    /**
     * Returns whether or not the specified data flavor is an HTML flavor that
     * is supported.
     * @param flavor the requested flavor for the data
     * @return boolean indicating whether or not the data flavor is supported
     */
    protected boolean isHTMLFlavor(DataFlavor flavor) {
        DataFlavor[] flavors = htmlFlavors;
        for (int i = 0; i < flavors.length; i++) {
            if (flavors[i].equals(flavor)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Should the HTML flavors be offered?  If so, the method
     * getHTMLData should be implemented to provide something reasonable.
     */
    protected boolean isHTMLSupported() {
        return htmlData != null;
    }

    /**
     * Fetch the data in a text/html format
     */
    protected String getHTMLData() {
        return htmlData;
    }

    // --- plain text flavors ----------------------------------------------------

    /**
     * Returns whether or not the specified data flavor is an plain flavor that
     * is supported.
     * @param flavor the requested flavor for the data
     * @return boolean indicating whether or not the data flavor is supported
     */
    protected boolean isPlainFlavor(DataFlavor flavor) {
        DataFlavor[] flavors = plainFlavors;
        for (int i = 0; i < flavors.length; i++) {
            if (flavors[i].equals(flavor)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Should the plain text flavors be offered?  If so, the method
     * getPlainData should be implemented to provide something reasonable.
     */
    protected boolean isPlainSupported() {
        return plainData != null;
    }

    /**
     * Fetch the data in a text/plain format.
     */
    protected String getPlainData() {
        return plainData;
    }

    // --- string flavorss --------------------------------------------------------

    /**
     * Returns whether or not the specified data flavor is a String flavor that
     * is supported.
     * @param flavor the requested flavor for the data
     * @return boolean indicating whether or not the data flavor is supported
     */
    protected boolean isStringFlavor(DataFlavor flavor) {
        DataFlavor[] flavors = stringFlavors;
        for (int i = 0; i < flavors.length; i++) {
            if (flavors[i].equals(flavor)) {
                return true;
            }
        }
        return false;
    }


}
