/*

 * Copyright 1997-2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.swing;

import javax.swing.plaf.*;

import javax.accessibility.*;

import java.io.ObjectOutputStream;

import java.io.ObjectInputStream;

import java.io.IOException;

/**

 * Used to display a "Tip" for a Component. Typically components provide api

 * to automate the process of using <code>ToolTip</code>s.

 * For example, any Swing component can use the <code>JComponent</code>

 * <code>setToolTipText</code> method to specify the text

 * for a standard tooltip. A component that wants to create a custom

 * <code>ToolTip</code>

 * display can override <code>JComponent</code>'s <code>createToolTip</code>

 * method and use a subclass of this class.

 * <p>

 * See <a href="http://java.sun.com/docs/books/tutorial/uiswing/components/tooltip.html">How to Use Tool Tips</a>

 * in <em>The Java Tutorial</em>

 * for further documentation.

 * <p>

 * <strong>Warning:</strong> Swing is not thread safe. For more

 * information see <a

 * href="package-summary.html#threading">Swing's Threading

 * Policy</a>.

 * <p>

 * <strong>Warning:</strong>

 * Serialized objects of this class will not be compatible with

 * future Swing releases. The current serialization support is

 * appropriate for short term storage or RMI between applications running

 * the same version of Swing.  As of 1.4, support for long term storage

 * of all JavaBeans<sup><font size="-2">TM</font></sup>

 * has been added to the <code>java.beans</code> package.

 * Please see {@link java.beans.XMLEncoder}.

 *

 * @see JComponent#setToolTipText

 * @see JComponent#createToolTip

 * @author Dave Moore

 * @author Rich Shiavi

 */

public class JToolTip extends JComponent implements Accessible {

    /**

     * @see #getUIClassID

     * @see #readObject

     */

    private static final String uiClassID = "ToolTipUI";

    String tipText;

    JComponent component;

    /** Creates a tool tip. */

    public JToolTip() {

        setOpaque(true);

        updateUI();

    }

    /**

     * Returns the L&F object that renders this component.

     *

     * @return the <code>ToolTipUI</code> object that renders this component

     */

    public ToolTipUI getUI() {

        return (ToolTipUI)ui;

    }

    /**

     * Resets the UI property to a value from the current look and feel.

     *

     * @see JComponent#updateUI

     */

    public void updateUI() {

        setUI((ToolTipUI)UIManager.getUI(this));

    }

    /**

     * Returns the name of the L&F class that renders this component.

     *

     * @return the string "ToolTipUI"

     * @see JComponent#getUIClassID

     * @see UIDefaults#getUI

     */

    public String getUIClassID() {

        return uiClassID;

    }

    /**

     * Sets the text to show when the tool tip is displayed.

     * The string <code>tipText</code> may be <code>null</code>.

     *

     * @param tipText the <code>String</code> to display

     * @beaninfo

     *    preferred: true

     *        bound: true

     *  description: Sets the text of the tooltip

     */

    public void setTipText(String tipText) {

        String oldValue = this.tipText;

        this.tipText = tipText;

        firePropertyChange("tiptext", oldValue, tipText);

    }

    /**

     * Returns the text that is shown when the tool tip is displayed.

     * The returned value may be <code>null</code>.

     *

     * @return the <code>String</code> that is displayed

     */

    public String getTipText() {

        return tipText;

    }

    /**

     * Specifies the component that the tooltip describes.

     * The component <code>c</code> may be <code>null</code>

     * and will have no effect.

     * <p>

     * This is a bound property.

     *

     * @param c the <code>JComponent</code> being described

     * @see JComponent#createToolTip

     * @beaninfo

     *       bound: true

     * description: Sets the component that the tooltip describes.

     */

    public void setComponent(JComponent c) {

        JComponent oldValue = this.component;

        component = c;

        firePropertyChange("component", oldValue, c);

    }

    /**

     * Returns the component the tooltip applies to.

     * The returned value may be <code>null</code>.

     *

     * @return the component that the tooltip describes

     *

     * @see JComponent#createToolTip

     */

    public JComponent getComponent() {

        return component;

    }

    /**

     * Always returns true since tooltips, by definition,

     * should always be on top of all other windows.

     */

    // package private

    boolean alwaysOnTop() {

        return true;

    }

    /**

     * See <code>readObject</code> and <code>writeObject</code>

     * in <code>JComponent</code> for more

     * information about serialization in Swing.

     */

    private void writeObject(ObjectOutputStream s) throws IOException {

        s.defaultWriteObject();

        if (getUIClassID().equals(uiClassID)) {

            byte count = JComponent.getWriteObjCounter(this);

            JComponent.setWriteObjCounter(this, --count);

            if (count == 0 && ui != null) {

                ui.installUI(this);

            }

        }

    }

    /**

     * Returns a string representation of this <code>JToolTip</code>.

     * This method

     * is intended to be used only for debugging purposes, and the

     * content and format of the returned string may vary between

     * implementations. The returned string may be empty but may not

     * be <code>null</code>.

     *

     * @return  a string representation of this <code>JToolTip</code>

     */

    protected String paramString() {

        String tipTextString = (tipText != null ?

                                tipText : "");

        return super.paramString() +

        ",tipText=" + tipTextString;

    }

/////////////////

// Accessibility support

////////////////

    /**

     * Gets the AccessibleContext associated with this JToolTip.

     * For tool tips, the AccessibleContext takes the form of an

     * AccessibleJToolTip.

     * A new AccessibleJToolTip instance is created if necessary.

     *

     * @return an AccessibleJToolTip that serves as the

     *         AccessibleContext of this JToolTip

     */

    public AccessibleContext getAccessibleContext() {

        if (accessibleContext == null) {

            accessibleContext = new AccessibleJToolTip();

        }

        return accessibleContext;

    }

    /**

     * This class implements accessibility support for the

     * <code>JToolTip</code> class.  It provides an implementation of the

     * Java Accessibility API appropriate to tool tip user-interface elements.

     * <p>

     * <strong>Warning:</strong>

     * Serialized objects of this class will not be compatible with

     * future Swing releases. The current serialization support is

     * appropriate for short term storage or RMI between applications running

     * the same version of Swing.  As of 1.4, support for long term storage

     * of all JavaBeans<sup><font size="-2">TM</font></sup>

     * has been added to the <code>java.beans</code> package.

     * Please see {@link java.beans.XMLEncoder}.

     */

    protected class AccessibleJToolTip extends AccessibleJComponent {

        /**

         * Get the accessible description of this object.

         *

         * @return a localized String describing this object.

         */

        public String getAccessibleDescription() {

            String description = accessibleDescription;

            // fallback to client property

            if (description == null) {

                description = (String)getClientProperty(AccessibleContext.ACCESSIBLE_DESCRIPTION_PROPERTY);

            }

            if (description == null) {

                description = getTipText();

            }

            return description;

        }

        /**

         * Get the role of this object.

         *

         * @return an instance of AccessibleRole describing the role of the

         * object

         */

        public AccessibleRole getAccessibleRole() {

            return AccessibleRole.TOOL_TIP;

        }

    }

}