/* java.beans.Introspector Copyright (C) 1998, 2002 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. */ package java.beans; import gnu.java.beans.*; import java.util.*; import java.lang.reflect.*; import gnu.java.lang.*; /** * Introspector is the class that does the bulk of the * design-time work in Java Beans. Every class must have * a BeanInfo in order for an RAD tool to use it; but, as * promised, you don't have to write the BeanInfo class * yourself if you don't want to. All you have to do is * call getBeanInfo() in the Introspector and it will use * standard JavaBeans-defined method signatures to * determine the information about your class.
* * Don't worry about it too much, though: you can provide * JavaBeans with as much customized information as you * want, or as little as you want, using the BeanInfo * interface (see BeanInfo for details).
* * Order of Operations
*
* When you call getBeanInfo(class c), the Introspector
* first searches for BeanInfo class to see if you
* provided any explicit information. It searches for a
* class named
*
* If it does not find a BeanInfo class, it acts as though
* it had found a BeanInfo class returning null from all
* methods (meaning it should discover everything through
* Introspection). If it does, then it takes the
* information it finds in the BeanInfo class to be
* canonical (that is, the information speaks for its
* class as well as all superclasses).
*
* When it has introspected the class, calls
* getBeanInfo(c.getSuperclass) and adds that information
* to the information it has, not adding to any information
* it already has that is canonical.
*
* Introspection Design Patterns
*
* When the Introspector goes in to read the class, it
* follows a well-defined order in order to not leave any
* methods unaccounted for. Its job is to step over all
* of the public methods in a class and determine whether
* they are part of a property, an event, or a method (in
* that order).
*
*
* Properties:
*
*
*
* If there is a pair of methods,
*
*
* If the addXXX() method throws
*
*
* Spec Note: the spec seems to say that
* the listener type's classname must be equal to the XXX
* part of addXXX() and removeXXX(), but that is not the
* case in Sun's implementation, so I am assuming it is
* not the case in general.
*
* Methods:
*
* Any public methods (including those which were used
* for Properties or Events) are used as Methods.
*
* @author John Keiser
* @since JDK1.1
* @see java.beans.BeanInfo
*/
public class Introspector {
public static final int USE_ALL_BEANINFO = 1;
public static final int IGNORE_IMMEDIATE_BEANINFO = 2;
public static final int IGNORE_ALL_BEANINFO = 3;
static String[] beanInfoSearchPath = {"gnu.java.beans.info"};
static Hashtable beanInfoCache = new Hashtable();
private Introspector() {}
/**
* Get the BeanInfo for class
*
*
* Events:public boolean isXXX()
* method, then XXX is a read-only boolean property.
* boolean getXXX()
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
* public void setXXX(boolean)
method,
* it is part of this group and makes it a read-write
* property.public <type> getXXX(int)
* method, then XXX is a read-only indexed property of
* type <type>. If there is a
* public void setXXX(int,<type>)
* method, then it is a read-write indexed property of
* type <type>. There may also be a
* public <type>[] getXXX()
and a
* public void setXXX(<type>)
* method as well.public void setXXX(int,<type>)
* method, then it is a write-only indexed property of
* type <type>. There may also be a
* public <type>[] getXXX()
and a
* public void setXXX(<type>)
* method as well.public <type> getXXX()
method,
* then XXX is a read-only property of type
* <type>. If there is a
* public void setXXX(<type>)
* method, then it will be used for the property and
* the property will be considered read-write.public void setXXX(<type>)
* 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>.PropertyVetoException
, then the
* property in question is assumed to be constrained.
* No properties are ever assumed to be bound
* (Spec Note: this is not in the
* spec, it just makes sense). See PropertyDescriptor
* for a description of bound and constrained
* properties.public void addXXX(<type>)
and
* public void removeXXX(<type>)
, where
* <type> is a descendant of
* java.util.EventListener
, then the pair of
* methods imply that this Bean will fire events to
* listeners of type <type>.java.util.TooManyListenersException
, then
* the event set is assumed to be unicast. See
* EventSetDescriptor for a discussion of unicast event
* sets.beanClass
,
* first by looking for explicit information, next by
* using standard design patterns to determine
* information about the class.
*
* @param beanClass the class to get BeanInfo about.
* @return the BeanInfo object representing the class.
*/
public static BeanInfo getBeanInfo(Class beanClass)
throws IntrospectionException
{
BeanInfo cachedInfo;
synchronized(beanClass)
{
cachedInfo = (BeanInfo)beanInfoCache.get(beanClass);
if(cachedInfo != null)
{
return cachedInfo;
}
cachedInfo = getBeanInfo(beanClass,null);
beanInfoCache.put(beanClass,cachedInfo);
return cachedInfo;
}
}
/**
* Flush all of the Introspector's internal caches.
*
* @since 1.2
*/
public static void flushCaches()
{
beanInfoCache.clear();
}
/**
* Flush the Introspector's internal cached information for a given
* class.
*
* @param clz the class to be flushed.
* @throws NullPointerException if clz is null.
* @since 1.2
*/
public static void flushFromCaches(Class clz)
{
synchronized (clz)
{
beanInfoCache.remove(clz);
}
}
/**
* Get the BeanInfo for class beanClass
,
* first by looking for explicit information, next by
* using standard design patterns to determine
* information about the class. It crawls up the
* inheritance tree until it hits topClass
.
*
* @param beanClass the Bean class.
* @param stopClass the class to stop at.
* @return the BeanInfo object representing the class.
*/
public static BeanInfo getBeanInfo(Class beanClass, Class stopClass)
throws IntrospectionException
{
ExplicitInfo explicit = new ExplicitInfo(beanClass,stopClass);
IntrospectionIncubator ii = new IntrospectionIncubator();
ii.setPropertyStopClass(explicit.propertyStopClass);
ii.setEventStopClass(explicit.eventStopClass);
ii.setMethodStopClass(explicit.methodStopClass);
ii.addMethods(beanClass.getMethods());
BeanInfoEmbryo currentInfo = ii.getBeanInfoEmbryo();
PropertyDescriptor[] p = explicit.explicitPropertyDescriptors;
if(p!=null)
{
for(int i=0;i