Home » openjdk-7 » java » beans » [javadoc | source]

    1   /*
    2    * Copyright (c) 1996, 2007, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   
   26   package java.beans;
   27   
   28   import java.beans;
   29   
   30   /**
   31    * This is a support class to help build property editors.
   32    * <p>
   33    * It can be used either as a base class or as a delagatee.
   34    */
   35   
   36   public class PropertyEditorSupport implements PropertyEditor {
   37   
   38       /**
   39        * Constructs a <code>PropertyEditorSupport</code> object.
   40        *
   41        * @since 1.5
   42        */
   43       public PropertyEditorSupport() {
   44           setSource(this);
   45       }
   46   
   47       /**
   48        * Constructs a <code>PropertyEditorSupport</code> object.
   49        *
   50        * @param source the source used for event firing
   51        * @since 1.5
   52        */
   53       public PropertyEditorSupport(Object source) {
   54           if (source == null) {
   55              throw new NullPointerException();
   56           }
   57           setSource(source);
   58       }
   59   
   60       /**
   61        * Returns the bean that is used as the
   62        * source of events. If the source has not
   63        * been explicitly set then this instance of
   64        * <code>PropertyEditorSupport</code> is returned.
   65        *
   66        * @return the source object or this instance
   67        * @since 1.5
   68        */
   69       public Object getSource() {
   70           return source;
   71       }
   72   
   73       /**
   74        * Sets the source bean.
   75        * <p>
   76        * The source bean is used as the source of events
   77        * for the property changes. This source should be used for information
   78        * purposes only and should not be modified by the PropertyEditor.
   79        *
   80        * @param source source object to be used for events
   81        * @since 1.5
   82        */
   83       public void setSource(Object source) {
   84           this.source = source;
   85       }
   86   
   87       /**
   88        * Set (or change) the object that is to be edited.
   89        *
   90        * @param value The new target object to be edited.  Note that this
   91        *     object should not be modified by the PropertyEditor, rather
   92        *     the PropertyEditor should create a new object to hold any
   93        *     modified value.
   94        */
   95       public void setValue(Object value) {
   96           this.value = value;
   97           firePropertyChange();
   98       }
   99   
  100       /**
  101        * Gets the value of the property.
  102        *
  103        * @return The value of the property.
  104        */
  105       public Object getValue() {
  106           return value;
  107       }
  108   
  109       //----------------------------------------------------------------------
  110   
  111       /**
  112        * Determines whether the class will honor the paintValue method.
  113        *
  114        * @return  True if the class will honor the paintValue method.
  115        */
  116   
  117       public boolean isPaintable() {
  118           return false;
  119       }
  120   
  121       /**
  122        * Paint a representation of the value into a given area of screen
  123        * real estate.  Note that the propertyEditor is responsible for doing
  124        * its own clipping so that it fits into the given rectangle.
  125        * <p>
  126        * If the PropertyEditor doesn't honor paint requests (see isPaintable)
  127        * this method should be a silent noop.
  128        *
  129        * @param gfx  Graphics object to paint into.
  130        * @param box  Rectangle within graphics object into which we should paint.
  131        */
  132       public void paintValue(java.awt.Graphics gfx, java.awt.Rectangle box) {
  133       }
  134   
  135       //----------------------------------------------------------------------
  136   
  137       /**
  138        * This method is intended for use when generating Java code to set
  139        * the value of the property.  It should return a fragment of Java code
  140        * that can be used to initialize a variable with the current property
  141        * value.
  142        * <p>
  143        * Example results are "2", "new Color(127,127,34)", "Color.orange", etc.
  144        *
  145        * @return A fragment of Java code representing an initializer for the
  146        *          current value.
  147        */
  148       public String getJavaInitializationString() {
  149           return "???";
  150       }
  151   
  152       //----------------------------------------------------------------------
  153   
  154       /**
  155        * Gets the property value as a string suitable for presentation
  156        * to a human to edit.
  157        *
  158        * @return The property value as a string suitable for presentation
  159        *       to a human to edit.
  160        * <p>   Returns null if the value can't be expressed as a string.
  161        * <p>   If a non-null value is returned, then the PropertyEditor should
  162        *       be prepared to parse that string back in setAsText().
  163        */
  164       public String getAsText() {
  165           return (this.value != null)
  166                   ? this.value.toString()
  167                   : null;
  168       }
  169   
  170       /**
  171        * Sets the property value by parsing a given String.  May raise
  172        * java.lang.IllegalArgumentException if either the String is
  173        * badly formatted or if this kind of property can't be expressed
  174        * as text.
  175        *
  176        * @param text  The string to be parsed.
  177        */
  178       public void setAsText(String text) throws java.lang.IllegalArgumentException {
  179           if (value instanceof String) {
  180               setValue(text);
  181               return;
  182           }
  183           throw new java.lang.IllegalArgumentException(text);
  184       }
  185   
  186       //----------------------------------------------------------------------
  187   
  188       /**
  189        * If the property value must be one of a set of known tagged values,
  190        * then this method should return an array of the tag values.  This can
  191        * be used to represent (for example) enum values.  If a PropertyEditor
  192        * supports tags, then it should support the use of setAsText with
  193        * a tag value as a way of setting the value.
  194        *
  195        * @return The tag values for this property.  May be null if this
  196        *   property cannot be represented as a tagged value.
  197        *
  198        */
  199       public String[] getTags() {
  200           return null;
  201       }
  202   
  203       //----------------------------------------------------------------------
  204   
  205       /**
  206        * A PropertyEditor may chose to make available a full custom Component
  207        * that edits its property value.  It is the responsibility of the
  208        * PropertyEditor to hook itself up to its editor Component itself and
  209        * to report property value changes by firing a PropertyChange event.
  210        * <P>
  211        * The higher-level code that calls getCustomEditor may either embed
  212        * the Component in some larger property sheet, or it may put it in
  213        * its own individual dialog, or ...
  214        *
  215        * @return A java.awt.Component that will allow a human to directly
  216        *      edit the current property value.  May be null if this is
  217        *      not supported.
  218        */
  219   
  220       public java.awt.Component getCustomEditor() {
  221           return null;
  222       }
  223   
  224       /**
  225        * Determines whether the propertyEditor can provide a custom editor.
  226        *
  227        * @return  True if the propertyEditor can provide a custom editor.
  228        */
  229       public boolean supportsCustomEditor() {
  230           return false;
  231       }
  232   
  233       //----------------------------------------------------------------------
  234   
  235       /**
  236        * Adds a listener for the value change.
  237        * When the property editor changes its value
  238        * it should fire a {@link PropertyChangeEvent}
  239        * on all registered {@link PropertyChangeListener}s,
  240        * specifying the {@code null} value for the property name.
  241        * If the source property is set,
  242        * it should be used as the source of the event.
  243        * <p>
  244        * The same listener object may be added more than once,
  245        * and will be called as many times as it is added.
  246        * If {@code listener} is {@code null},
  247        * no exception is thrown and no action is taken.
  248        *
  249        * @param listener  the {@link PropertyChangeListener} to add
  250        */
  251       public synchronized void addPropertyChangeListener(
  252                                   PropertyChangeListener listener) {
  253           if (listeners == null) {
  254               listeners = new java.util.Vector();
  255           }
  256           listeners.addElement(listener);
  257       }
  258   
  259       /**
  260        * Removes a listener for the value change.
  261        * <p>
  262        * If the same listener was added more than once,
  263        * it will be notified one less time after being removed.
  264        * If {@code listener} is {@code null}, or was never added,
  265        * no exception is thrown and no action is taken.
  266        *
  267        * @param listener  the {@link PropertyChangeListener} to remove
  268        */
  269       public synchronized void removePropertyChangeListener(
  270                                   PropertyChangeListener listener) {
  271           if (listeners == null) {
  272               return;
  273           }
  274           listeners.removeElement(listener);
  275       }
  276   
  277       /**
  278        * Report that we have been modified to any interested listeners.
  279        */
  280       public void firePropertyChange() {
  281           java.util.Vector targets;
  282           synchronized (this) {
  283               if (listeners == null) {
  284                   return;
  285               }
  286               targets = (java.util.Vector) listeners.clone();
  287           }
  288           // Tell our listeners that "everything" has changed.
  289           PropertyChangeEvent evt = new PropertyChangeEvent(source, null, null, null);
  290   
  291           for (int i = 0; i < targets.size(); i++) {
  292               PropertyChangeListener target = (PropertyChangeListener)targets.elementAt(i);
  293               target.propertyChange(evt);
  294           }
  295       }
  296   
  297       //----------------------------------------------------------------------
  298   
  299       private Object value;
  300       private Object source;
  301       private java.util.Vector listeners;
  302   }

Home » openjdk-7 » java » beans » [javadoc | source]