java/11 : java.desktop/java/beans/PropertyEditor.java

PropertyEditor
https://openjdk.java.net/
GPLv2 + Classpath Exception
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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.

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.

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.

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().

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.

Each PropertyEditor should have a null constructor.
Since: 1.1/**
 * 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.
 *
 * @since 1.1
 */

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".
Params: 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./**
     * 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.
Returns: The value of the property.  Primitive types such as "int" will
be wrapped as the corresponding object type such as "java.lang.Integer"./**
     * 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.
Returns:  True if the class will honor the paintValue method./**
     * 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.

If the PropertyEditor doesn't honor paint requests (see isPaintable)
this method should be a silent noop.

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.
Params: gfx –  Graphics object to paint into.
box –  Rectangle within graphics object into which we should paint./**
     * 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.

The code fragment should be context free and must be a legal Java
expression as specified by the JLS.

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.

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.

Example results are:

Primitive expresssion: 2 
Class constructor: new java.awt.Color(127,127,34) 
Static field: java.awt.Color.orange 
Static method: javax.swing.Box.createRigidArea(new
                                  java.awt.Dimension(0, 5)) 
Returns: a fragment of Java code representing an initializer for the current value. It should not contain a semi-colon (';') to end the expression./**
     * 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}
     * <li>Class constructor: {@code new java.awt.Color(127,127,34)}
     * <li>Static field: {@code java.awt.Color.orange}
     * <li>Static method: {@code javax.swing.Box.createRigidArea(new
     *                                   java.awt.Dimension(0, 5))}
     * </ul>
     *
     * @return a fragment of Java code representing an initializer for the
     *         current value. It should not contain a semi-colon
     *         ('{@code ;}') to end the expression.
     */
    String getJavaInitializationString();

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

    Gets the property value as text.
Returns: The property value as a human editable string.
   Returns null if the value can't be expressed as an editable string.
   If a non-null value is returned, then the PropertyEditor should
      be prepared to parse that string back in setAsText()./**
     * 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.
Params: text –  The string to be parsed./**
     * 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.
Returns: The tag values for this property.  May be null if this
  property cannot be represented as a tagged value./**
     * 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.

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 ...
Returns: A java.awt.Component that will allow a human to directly
     edit the current property value.  May be null if this is
     not supported./**
     * 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.
Returns:  True if the propertyEditor can provide a custom editor./**
     * 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 PropertyChangeEvent on all registered PropertyChangeListeners, specifying the null value for the property name and itself as the source. 
Params: listener –  the PropertyChangeListener to add/**
     * 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.
Params: listener –  the PropertyChangeListener to remove/**
     * Removes a listener for the value change.
     *
     * @param listener  the {@link PropertyChangeListener} to remove
     */
    void removePropertyChangeListener(PropertyChangeListener listener);

}
/

java/ 11/ java.desktop/java/beans/PropertyEditor.java
