/* * @(#)PropertyEditor.java 1.37 03/12/19 * * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ 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. */ 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. *

* 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. * * @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: *

* * @return a fragment of Java code representing an initializer for the * current value. It should not contain a semi-colon * (';') to end the expression. */ String getJavaInitializationString(); //---------------------------------------------------------------------- /** * Gets the property value as text. * * @return 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(). */ 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. *

* 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(); //---------------------------------------------------------------------- /** * Register a listener for the PropertyChange event. When a * PropertyEditor changes its value it should fire a PropertyChange * event on all registered PropertyChangeListeners, specifying the * null value for the property name and itself as the source. * * @param listener An object to be invoked when a PropertyChange * event is fired. */ void addPropertyChangeListener(PropertyChangeListener listener); /** * Remove a listener for the PropertyChange event. * * @param listener The PropertyChange listener to be removed. */ void removePropertyChangeListener(PropertyChangeListener listener); }