libjava/java/beans/BeanInfo.java

   1 /* java.beans.BeanInfo
   2    Copyright (C) 1998 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.beans;
  40
  41 /**
  42  ** BeanInfo can be implemented in order to provide explicit information to the Introspector.
  43  **
  44  ** When you write a BeanInfo class, you implement this interface
  45  ** and provide explicit information by returning a non-null
  46  ** value from the appropriate method.  If you wish the
  47  ** Introspector to determine certain information in the normal
  48  ** way, just return null (or in the case of int methods, return
  49  ** -1).  There is a class called SimpleBeanInfo which returns
  50  ** null from all methods, which you may extend and only
  51  ** override the methods you wish to override.<P>
  52  **
  53  ** When you have written the class, give it the name
  54  ** <CODE>&lt;Bean Class Name&gt;BeanInfo</CODE> and place it in
  55  ** the same package as the Bean, or in the bean info search path
  56  ** (see Introspector for information on search paths).<P>
  57  **
  58  ** A simple note about the way the Introspector interacts with
  59  ** BeanInfo.  Introspectors look at a Bean class and determine
  60  ** if there is a BeanInfo class with it.  If there is not a
  61  ** BeanInfo class, it will behave as if the BeanInfo class
  62  ** provided was a SimpleBeanInfo class (i.e. it will determine
  63  ** all information automatically).<P>If there is a BeanInfo
  64  ** class, then any methods that do *not* return null are
  65  ** regarded as providing definitive information about the class
  66  ** and all of its superclasses for those information types.
  67  ** Even if a parent BeanInfo class explicitly returns that
  68  ** information, it will not be used.
  69  **
  70  ** @author John Keiser
  71  ** @since JDK1.1
  72  ** @version 1.1.0, 28 Jul 1998
  73  **/
  74
  75 public interface BeanInfo {
  76         /** Use this as a parameter for the getIcon() command to retrieve a certain type of icon. **/
  77         int ICON_COLOR_16x16 = 1;
  78         /** Use this as a parameter for the getIcon() command to retrieve a certain type of icon. **/
  79         int ICON_COLOR_32x32 = 2;
  80         /** Use this as a parameter for the getIcon() command to retrieve a certain type of icon. **/
  81         int ICON_MONO_16x16 = 3;
  82         /** Use this as a parameter for the getIcon() command to retrieve a certain type of icon. **/
  83         int ICON_MONO_32x32 = 4;
  84
  85         /** Get the general description of this Bean type.
  86          ** @return the BeanDescriptor for the Bean, or null if
  87          **         the BeanDescriptor should be obtained by
  88          **         Introspection.
  89          **/
  90         BeanDescriptor getBeanDescriptor();
  91
  92         /** Get the events this Bean type fires.
  93          ** @return the EventDescriptors representing events this
  94          **         Bean fires.  Returns <CODE>null</CODE> if the
  95          **         events are to be acquired by Introspection.
  96          **/
  97         EventSetDescriptor[] getEventSetDescriptors();
  98
  99         /** Get the "default" event, basically the one a RAD tool
 100          ** user is most likely to select.
 101          ** @return the index into the getEventSetDescriptors()
 102          **         that the user is most likely to use.  Returns
 103          **         <CODE>-1</CODE> if there is no default event.
 104          **/
 105         int getDefaultEventIndex();
 106
 107         /** Get the properties (get/set method pairs) this Bean
 108          ** type supports.
 109          ** @return the PropertyDescriptors representing the
 110          **         properties this Bean type supports.
 111          **         Returns <CODE>null</CODE> if the properties
 112          **         are to be obtained by Introspection.
 113          **/
 114         PropertyDescriptor[] getPropertyDescriptors();
 115
 116         /** Get the "default" property, basically the one a RAD
 117          ** tool user is most likely to select.
 118          ** @return the index into the getPropertyDescriptors()
 119          **         that the user is most likely to use.  Returns
 120          **         <CODE>-1</CODE> if there is no default event.
 121          **/
 122         int getDefaultPropertyIndex();
 123
 124         /** Get the methods this Bean type supports.
 125          ** @return the MethodDescriptors representing the
 126          **         methods this Bean type supports.  Returns
 127          **         <CODE>null</CODE> if the methods are to be
 128          **         obtained by Introspection.
 129          **/
 130         MethodDescriptor[] getMethodDescriptors();
 131
 132         /** Get additional BeanInfos representing this Bean.
 133          ** In this version of JavaBeans, this method is used so
 134          ** that space and time can be saved by reading a BeanInfo
 135          ** for each class in the hierarchy (super, super(super),
 136          ** and so on).<P>
 137          **
 138          ** The order of precedence when two pieces of BeanInfo
 139          ** conflict (such as two PropertyDescriptors that have
 140          ** the same name), in order from highest precedence to
 141          ** lowest, is:
 142          ** <OL>
 143          ** <LI>This BeanInfo object.</LI>
 144          ** <LI><CODE>getAdditionalBeanInfo()[getAdditionalBeanInfo().length]</CODE></LI>
 145          ** <LI> ... </LI>
 146          ** <LI><CODE>getAdditionalBeanInfo()[1]</CODE></LI>
 147          ** <LI><CODE>getAdditionalBeanInfo()[0]</CODE></LI>
 148          ** </OL><P>
 149          **
 150          ** <STRONG>Spec Note:</STRONG> It is possible that
 151          ** returning <CODE>null</CODE> from this method could
 152          ** stop Introspection in its tracks, but it is unclear
 153          ** from the spec whether this is the case.
 154          **
 155          ** @return additional BeanInfos representing this Bean.
 156          **         <CODE>null</CODE> may be returned (see Spec
 157          **         Note, above).
 158          **/
 159         BeanInfo[] getAdditionalBeanInfo();
 160
 161         /** Get a visual icon for this Bean.
 162          ** A Bean does not have to support icons, and if it does
 163          ** support icons, it does not have to support every single
 164          ** type.  Sun recommends that if you only support one
 165          ** type, you support 16x16 color.  Sun also notes that you
 166          ** should try to use a type (like GIF) that allows for
 167          ** transparent pixels, so that the background of the RAD
 168          ** tool can show through.<P>
 169          **
 170          ** <STRONG>Spec Note:</STRONG> If you do not support the
 171          ** type of icon that is being asked for, but you do
 172          ** support another type, it is unclear whether you should
 173          ** return the other type or not.  I would presume not.
 174          **
 175          ** @param iconType the type of icon to get (see the
 176          **        ICON_* constants in this class).
 177          ** @return the icon, or null if that type of icon is
 178          **         unsupported by this Bean.
 179          **/
 180         java.awt.Image getIcon(int iconType);
 181 }