* createPropertyDescriptor("contentPane", new Object[] {
* BOUND, Boolean.TRUE,
* CONSTRAINED, Boolean.TRUE,
* PROPERTYEDITORCLASS, package.MyEditor.class,
* READMETHOD, "getContentPane",
* WRITEMETHOD, "setContentPane",
* DISPLAYNAME, "contentPane",
* EXPERT, Boolean.FALSE,
* HIDDEN, Boolean.FALSE,
* PREFERRED, Boolean.TRUE,
* SHORTDESCRIPTION, "A top level window with a window manager border",
* "random attribute","random object value"
* }
* );
*
* The keywords correspond to java.beans.PropertyDescriptor and
* java.beans.FeatureDescriptor properties, e.g. providing a value
* for displayName is comparable to FeatureDescriptor.setDisplayName().
* Using createPropertyDescriptor instead of the PropertyDescriptor
* constructor and set methods is preferrable in that it regularizes
* the code in a java.beans.BeanInfo.getPropertyDescriptors()
* method implementation. One can use createPropertyDescriptor
* to set FeatureDescriptor attributes, as in "random attribute"
* "random object value".
*
* All properties should provide a reasonable value for the
* SHORTDESCRIPTION keyword and should set BOUND
* to Boolean.TRUE if neccessary. The remaining keywords
* are optional. There's no need to provide values for keywords like
* READMETHOD if the correct value can be computed, i.e. if the properties
* get/is method follows the standard beans pattern.
*
* The PREFERRED keyword is not supported by the JDK1.1 java.beans package. * It's still worth setting it to true for properties that are most * likely to be interested to the average developer, e.g. AbstractButton.title * is a preferred property, AbstractButton.focusPainted is not. * * @see java.beans#BeanInfo * @see java.beans#PropertyDescriptor * @see java.beans#FeatureDescriptor */ public static PropertyDescriptor createPropertyDescriptor(Class cls, String name, Object[] args) { PropertyDescriptor pd = null; try { pd = new PropertyDescriptor(name, cls); } catch (IntrospectionException e) { // Try creating a read-only property, in case setter isn't defined. try { pd = createReadOnlyPropertyDescriptor(name, cls); } catch (IntrospectionException ie) { throwError(ie, "Can't create PropertyDescriptor for " + name + " "); } } for(int i = 0; i < args.length; i += 2) { String key = (String)args[i]; Object value = args[i + 1]; if (BOUND.equals(key)) { pd.setBound(((Boolean)value).booleanValue()); } else if (CONSTRAINED.equals(key)) { pd.setConstrained(((Boolean)value).booleanValue()); } else if (PROPERTYEDITORCLASS.equals(key)) { pd.setPropertyEditorClass((Class)value); } else if (READMETHOD.equals(key)) { String methodName = (String)value; Method method; try { method = cls.getMethod(methodName, new Class[0]); pd.setReadMethod(method); } catch(Exception e) { throwError(e, cls + " no such method as \"" + methodName + "\""); } } else if (WRITEMETHOD.equals(key)) { String methodName = (String)value; Method method; try { Class type = pd.getPropertyType(); method = cls.getMethod(methodName, new Class[]{type}); pd.setWriteMethod(method); } catch(Exception e) { throwError(e, cls + " no such method as \"" + methodName + "\""); } } else { initFeatureDescriptor(pd, key, value); } } return pd; } /** * Create a BeanDescriptor object given an of keyword/value * arguments. The following sample call shows all of the supported * keywords: *
* createBeanDescriptor(JWindow..class, new Object[] {
* CUSTOMIZERCLASS, package.MyCustomizer.class,
* DISPLAYNAME, "JFrame",
* EXPERT, Boolean.FALSE,
* HIDDEN, Boolean.FALSE,
* PREFERRED, Boolean.TRUE,
* SHORTDESCRIPTION, "A top level window with a window manager border",
* "random attribute","random object value"
* }
* );
*
* The keywords correspond to java.beans.BeanDescriptor and
* java.beans.FeatureDescriptor properties, e.g. providing a value
* for displayName is comparable to FeatureDescriptor.setDisplayName().
* Using createBeanDescriptor instead of the BeanDescriptor
* constructor and set methods is preferrable in that it regularizes
* the code in a java.beans.BeanInfo.getBeanDescriptor()
* method implementation. One can use createBeanDescriptor
* to set FeatureDescriptor attributes, as in "random attribute"
* "random object value".
*
* @see java.beans#BeanInfo
* @see java.beans#PropertyDescriptor
*/
public static BeanDescriptor createBeanDescriptor(Class cls, Object[] args)
{
Class customizerClass = null;
/* For reasons I don't understand, customizerClass is a
* readOnly property. So we have to find it and pass it
* to the constructor here.
*/
for(int i = 0; i < args.length; i += 2) {
if (CUSTOMIZERCLASS.equals((String)args[i])) {
customizerClass = (Class)args[i + 1];
break;
}
}
BeanDescriptor bd = new BeanDescriptor(cls, customizerClass);
for(int i = 0; i < args.length; i += 2) {
String key = (String)args[i];
Object value = args[i + 1];
initFeatureDescriptor(bd, key, value);
}
return bd;
}
static private PropertyDescriptor createReadOnlyPropertyDescriptor(
String name, Class cls) throws IntrospectionException {
Method readMethod = null;
String base = capitalize(name);
Class[] parameters = new Class[0];
// Is it a boolean?
try {
readMethod = cls.getMethod("is" + base, parameters);
} catch (Exception ex) {}
if (readMethod == null) {
try {
// Try normal accessor pattern.
readMethod = cls.getMethod("get" + base, parameters);
} catch (Exception ex2) {}
}
if (readMethod != null) {
return new PropertyDescriptor(name, readMethod, null);
}
try {
// Try indexed accessor pattern.
parameters = new Class[1];
parameters[0] = int.class;
readMethod = cls.getMethod("get" + base, parameters);
} catch (NoSuchMethodException nsme) {
throw new IntrospectionException(
"cannot find accessor method for " + name + " property.");
}
return new IndexedPropertyDescriptor(name, null, null, readMethod, null);
}
// Modified methods from java.beans.Introspector
private static String capitalize(String s) {
if (s.length() == 0) {
return s;
}
char chars[] = s.toCharArray();
chars[0] = Character.toUpperCase(chars[0]);
return new String(chars);
}
/**
* Fatal errors are handled by calling this method.
*/
public static void throwError(Exception e, String s) {
throw new Error(e.toString() + " " + s);
}
}