From: Tim Wilkinson (tim@transvirtual.com)
Date: Thu Feb 04 1999 - 14:32:34 EST
Okay - I'll take a look at this as part of my "I hate bloody serialization but I
suppose I should get it working" stuff I'm doing now.
Cheers
Tim
Godmar Back wrote:
> Tim, have you been working on this?
> Does anybody know where this is speced out?
>
> I changed it such that it would include the names (as pointed out by Mo)
> and that it would include a property only if it has a set and get method.
> Is this what "editable" means? Or such I look for a write method only?
>
> Consider this test:
>
> // Start file PropertyDescriptorBug.java
>
> import java.lang.reflect.*;
> import java.beans.*;
> import java.util.*;
>
> public class PropertyDescriptorBug {
> public static void main(String[] argv) throws Exception {
>
> Class cls = java.awt.Button.class;
>
> BeanInfo beanInfo = Introspector.getBeanInfo(cls);
>
> PropertyDescriptor descriptors[] = beanInfo.getPropertyDescriptors();
>
> for (int i = 0; i < descriptors.length; i++) {
> if (descriptors[i] == null) {
> throw new NullPointerException("descriptor is null");
> }
> if (descriptors[i].getName() == null) {
> throw new NullPointerException("descriptor.getName() is null");
> }
>
> System.out.println(descriptors[i].getClass().getName()
> + " name is " + descriptors[i].getName());
> }
>
> }
> }
>
> // End file PropertyDescriptorBug.java
>
> With Sun's JDK:
>
> /usr/local/jdk1.1.7/bin/java PropertyDescriptorBug
> java.beans.PropertyDescriptor name is enabled
> java.beans.PropertyDescriptor name is actionCommand
> java.beans.PropertyDescriptor name is foreground
> java.beans.PropertyDescriptor name is label
> java.beans.PropertyDescriptor name is visible
> java.beans.PropertyDescriptor name is background
> java.beans.PropertyDescriptor name is font
> java.beans.PropertyDescriptor name is name
>
> With Kaffe + classpath's java.beans:
>
> java.beans.PropertyDescriptor name is visible
> java.beans.PropertyDescriptor name is background
> java.beans.PropertyDescriptor name is enabled
> java.beans.PropertyDescriptor name is foreground
> java.beans.PropertyDescriptor name is actionCommand
> java.beans.PropertyDescriptor name is label
> java.beans.PropertyDescriptor name is name
> java.beans.PropertyDescriptor name is font
>
> With Kaffe only (after my latest checkins)
>
> java.beans.PropertyDescriptor name is enabled
> java.beans.PropertyDescriptor name is foreground
> java.beans.PropertyDescriptor name is bounds
> java.beans.PropertyDescriptor name is visible
> java.beans.PropertyDescriptor name is actionCommand
> java.beans.PropertyDescriptor name is label
> java.beans.PropertyDescriptor name is name
> java.beans.PropertyDescriptor name is font
> java.beans.PropertyDescriptor name is cursor
> java.beans.PropertyDescriptor name is background
> java.beans.IndexedPropertyDescriptor name is size
> java.beans.IndexedPropertyDescriptor name is location
> java.beans.PropertyDescriptor name is locale
>
> Why don't they include "locale"? It has a
> "public void setLocale(Locale)" and a "public Locale getLocale()"
>
> Btw, I found this in classpath's java/beans/ implementation:
>
> ** <STRONG>Properties:</STRONG><P>
> **
> ** <OL>
> ** <LI>If there is a <CODE>public boolean isXXX()</CODE>
> ** method, then XXX is a read-only boolean property.
> ** <CODE>boolean getXXX()</CODE> may be supplied in
> ** addition to this method, although isXXX() is the
> ** one that will be used in this case and getXXX()
> ** will be ignored. If there is a
> ** <CODE>public void setXXX(boolean)</CODE> method,
> ** it is part of this group and makes it a read-write
> ** property.</LI>
> ** <LI>If there is a
> ** <CODE>public <type> getXXX(int)</CODE>
> ** method, then XXX is a read-only indexed property of
> ** type <type>. If there is a
> ** <CODE>public void setXXX(int,<type>)</CODE>
> ** method, then it is a read-write indexed property of
> ** type <type>. There may also be a
> ** <CODE>public <type>[] getXXX()</CODE> and a
> ** <CODE>public void setXXX(<type>)</CODE>
> ** method as well.</CODE></LI>
> ** <LI>If there is a
> ** <CODE>public void setXXX(int,<type>)</CODE>
> ** method, then it is a write-only indexed property of
> ** type <type>. There may also be a
> ** <CODE>public <type>[] getXXX()</CODE> and a
> ** <CODE>public void setXXX(<type>)</CODE>
> ** method as well.</CODE></LI>
> ** <LI>If there is a
> ** <CODE>public <type> getXXX()</CODE> method,
> ** then XXX is a read-only property of type
> ** <type>. If there is a
> ** <CODE>public void setXXX(<type>)</CODE>
> ** method, then it will be used for the property and
> ** the property will be considered read-write.</LI>
> ** <LI>If there is a
> ** <CODE>public void setXXX(<type>)</CODE>
> ** method, then as long as XXX is not already used as
> ** the name of a property, XXX is assumed to be a
> ** write-only property of type <type>.</LI>
> ** <LI>In all of the above cases, if the setXXX() method
> ** throws <CODE>PropertyVetoException</CODE>, then the
> ** property in question is assumed to be constrained.
> ** No properties are ever assumed to be bound
> ** (<STRONG>Spec Note:</STRONG> this is not in the
> ** spec, it just makes sense). See PropertyDescriptor
> ** for a description of bound and constrained
> ** properties.</LI>
> ** </OL>
>
> - Godmar
-- Tim Wilkinson Tel: +1 510 704 1660 Transvirtual Technologies, Inc., Fax: +1 510 704 1893 Berkeley, CA, USA. Email: tim@transvirtual.com
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