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 * Copyright (c) 1996, 2003, Oracle and/or its affiliates. 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.  Oracle designates this

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

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package java.beans;

/**

 * A PropertyEditor class provides support for GUIs that want to

 * allow users to edit a property value of a given type.

 * <p>

 * PropertyEditor supports a variety of different kinds of ways of

 * displaying and updating property values.  Most PropertyEditors will

 * only need to support a subset of the different options available in

 * this API.

 * <P>

 * Simple PropertyEditors may only support the getAsText and setAsText

 * methods and need not support (say) paintValue or getCustomEditor.  More

 * complex types may be unable to support getAsText and setAsText but will

 * instead support paintValue and getCustomEditor.

 * <p>

 * Every propertyEditor must support one or more of the three simple

 * display styles.  Thus it can either (1) support isPaintable or (2)

 * both return a non-null String[] from getTags() and return a non-null

 * value from getAsText or (3) simply return a non-null String from

 * getAsText().

 * <p>

 * Every property editor must support a call on setValue when the argument

 * object is of the type for which this is the corresponding propertyEditor.

 * In addition, each property editor must either support a custom editor,

 * or support setAsText.

 * <p>

 * Each PropertyEditor should have a null constructor.

 */

public interface PropertyEditor {

    /**

     * Set (or change) the object that is to be edited.  Primitive types such

     * as "int" must be wrapped as the corresponding object type such as

     * "java.lang.Integer".

     *

     * @param value The new target object to be edited.  Note that this

     *     object should not be modified by the PropertyEditor, rather

     *     the PropertyEditor should create a new object to hold any

     *     modified value.

     */

    void setValue(Object value);

    /**

     * Gets the property value.

     *

     * @return The value of the property.  Primitive types such as "int" will

     * be wrapped as the corresponding object type such as "java.lang.Integer".

     */

    Object getValue();

    //----------------------------------------------------------------------

    /**

     * Determines whether this property editor is paintable.

     *

     * @return  True if the class will honor the paintValue method.

     */

    boolean isPaintable();

    /**

     * Paint a representation of the value into a given area of screen

     * real estate.  Note that the propertyEditor is responsible for doing

     * its own clipping so that it fits into the given rectangle.

     * <p>

     * If the PropertyEditor doesn't honor paint requests (see isPaintable)

     * this method should be a silent noop.

     * <p>

     * The given Graphics object will have the default font, color, etc of

     * the parent container.  The PropertyEditor may change graphics attributes

     * such as font and color and doesn't need to restore the old values.

     *

     * @param gfx  Graphics object to paint into.

     * @param box  Rectangle within graphics object into which we should paint.

     */

    void paintValue(java.awt.Graphics gfx, java.awt.Rectangle box);

    //----------------------------------------------------------------------

    /**

     * Returns a fragment of Java code that can be used to set a property

     * to match the editors current state. This method is intended

     * for use when generating Java code to reflect changes made through the

     * property editor.

     * <p>

     * The code fragment should be context free and must be a legal Java

     * expression as specified by the JLS.

     * <p>

     * Specifically, if the expression represents a computation then all

     * classes and static members should be fully qualified. This rule

     * applies to constructors, static methods and non primitive arguments.

     * <p>

     * Caution should be used when evaluating the expression as it may throw

     * exceptions. In particular, code generators must ensure that generated

     * code will compile in the presence of an expression that can throw

     * checked exceptions.

     * <p>

     * Example results are:

     * <ul>

     * <li>Primitive expresssion: <code>2</code>

     * <li>Class constructor: <code>new java.awt.Color(127,127,34)</code>

     * <li>Static field: <code>java.awt.Color.orange</code>

     * <li>Static method: <code>javax.swing.Box.createRigidArea(new

     *                                   java.awt.Dimension(0, 5))</code>

     * </ul>

     *

     * @return a fragment of Java code representing an initializer for the

     *         current value. It should not contain a semi-colon

     *         ('<code>;</code>') to end the expression.

     */

    String getJavaInitializationString();

    //----------------------------------------------------------------------

    /**

     * Gets the property value as text.

     *

     * @return The property value as a human editable string.

     * <p>   Returns null if the value can't be expressed as an editable string.

     * <p>   If a non-null value is returned, then the PropertyEditor should

     *       be prepared to parse that string back in setAsText().

     */

    String getAsText();

    /**

     * Set the property value by parsing a given String.  May raise

     * java.lang.IllegalArgumentException if either the String is

     * badly formatted or if this kind of property can't be expressed

     * as text.

     * @param text  The string to be parsed.

     */

    void setAsText(String text) throws java.lang.IllegalArgumentException;

    //----------------------------------------------------------------------

    /**

     * If the property value must be one of a set of known tagged values,

     * then this method should return an array of the tags.  This can

     * be used to represent (for example) enum values.  If a PropertyEditor

     * supports tags, then it should support the use of setAsText with

     * a tag value as a way of setting the value and the use of getAsText

     * to identify the current value.

     *

     * @return The tag values for this property.  May be null if this

     *   property cannot be represented as a tagged value.

     *

     */

    String[] getTags();

    //----------------------------------------------------------------------

    /**

     * A PropertyEditor may choose to make available a full custom Component

     * that edits its property value.  It is the responsibility of the

     * PropertyEditor to hook itself up to its editor Component itself and

     * to report property value changes by firing a PropertyChange event.

     * <P>

     * The higher-level code that calls getCustomEditor may either embed

     * the Component in some larger property sheet, or it may put it in

     * its own individual dialog, or ...

     *

     * @return A java.awt.Component that will allow a human to directly

     *      edit the current property value.  May be null if this is

     *      not supported.

     */

    java.awt.Component getCustomEditor();

    /**

     * Determines whether this property editor supports a custom editor.

     *

     * @return  True if the propertyEditor can provide a custom editor.

     */

    boolean supportsCustomEditor();

    //----------------------------------------------------------------------

    /**

     * Adds a listener for the value change.

     * When the property editor changes its value

     * it should fire a {@link PropertyChangeEvent}

     * on all registered {@link PropertyChangeListener}s,

     * specifying the {@code null} value for the property name

     * and itself as the source.

     *

     * @param listener  the {@link PropertyChangeListener} to add

     */

    void addPropertyChangeListener(PropertyChangeListener listener);

    /**

     * Removes a listener for the value change.

     *

     * @param listener  the {@link PropertyChangeListener} to remove

     */

    void removePropertyChangeListener(PropertyChangeListener listener);

}