java.beans.beancontext
Interface BeanContext
- BeanContextChild, Collection<E>, DesignMode, Iterable<E>, Visibility
- BeanContextServices
- BeanContextServicesSupport, BeanContextSupport
Acts as a container for sub-beans and as a sub-bean,
so that an entire hierarchy of beans can be made up of
BeanContexts.
Since I can't sprinkle the
Collections interface
documentation with special information for
BeanContext
implementors, I'll have to document special requirements for
implementors of those functions here.
add() or
addAll():
-
May add any
Object into the hierarchy as well as a
BeanContextChild, BeanContext or
BeanContextProxy object.
This way, any Bean can be in the hierarchy.
-
Must synchronize on
BeanContext.globalHierarchyLock.
-
Don't add the
Object if it's already there (only once
per BeanContext).
-
If it is a
BeanContextChild implementor, call
setBeanContext() on it. If it's a
BeanContextProxy implementor, call
getBeanContextProxy().setBeanContext() on it.
If setBeanContext() vetoes the change, back out
all changes so far and throw IllegalStateException.
-
If it (or its proxy) implements
Visibility, call
dontUseGui() or okToUseGui() on it,
depending on whether you (the BeanContext) feel like
allowing it to use the GUI or not.
-
If it implements
BeanContextChild or
BeanContextProxy, register yourself (the
BeanContext) as both a
PropertyChangeListener and
VetoableChangeListener on the "beanContext"
property (it may also add itself on any other properties it wishes
to).
-
If it is a listener or event source that you (the
BeanContext) are interested in, you may register
yourself to it or register it to you.
-
Fire a
java.beans.beancontext.BeanContextMembershipEvent
before exiting. addAll() should wait until everything
is done changing before firing the event (or events) so that if a
failure occurs, the backing-out process can proceed without any
events being fired at all.
remove() or
removeAll():
-
Must synchronize on
BeanContext.globalHierarchyLock.
-
If the specified
Object is not a child of this
BeanContext, just exit without performing any actions.
-
Remove the
Object from your collection of children.
-
If it is a
BeanContextChild implementor, call
setBeanContext(null) on it. If it's a
BeanContextProxy implementor, call
getBeanContextProxy().setBeanContext(null) on it.
If setBeanContext() vetoes the change, back out
all changes so far and throw IllegalStateException.
-
If you registered the
Object to listen to you or
registered yourself as a listener on the Object during
add() or addAll(), undo the registration
bycalling the appropriate removeListener() method.
-
Fire a
java.beans.beancontext.BeanContextMembershipEvent
before exiting. removeAll() should wait until
everything is done changing before firing the event (or events) so
that if a failure occurs, the backing-out process can proceed
without any events being fired at all.
addAll(),
removeAll(),
retainAll() and
clear() do not need to be
implemented, but may be if so desired.
Similarly,
Visibility and
DesignMode methods
should propagate changed values to children that implement interfaces
of the same name.
A hierarchy of beans is mainly useful so that different sets of beans
can be established, each with their own set of resources.
T[] toArray, add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray |
globalHierarchyLock
public static final Object globalHierarchyLock
The global lock on changing any BeanContext hierarchy.
It kinda sucks that there is only one lock, since there can be
multiple hierarchies. Oh well, I didn't design, I just code.
Methods that must (or do) synchronize on the global lock:
-
Implementors of
BeanContext.add() and addAll()
getResource
public URL getResource(String resourceName,
BeanContextChild requestor) Get a resource. The
BeanContext will typically
call
ClassLoader.getResource(), but may do it any
way it wants to. This allows a
BeanContext to
have its own set of resources separate from the rest of the
system.
Beans should call this method on their parent rather than the
associated
ClassLoader method.
I am assuming, but am not entirely sure, that if a
BeanContext cannot find a resource, its
responsibility is to call the
getResource method
of its parent
BeanContext.
resourceName - the name of the resource requested.requestor - a reference to the child requesting the resource.
- a URL to the requested resource.
getResourceAsStream
public InputStream getResourceAsStream(String resourceName,
BeanContextChild requestor) Get a resource as a stream. The
BeanContext will
typically call
ClassLoader.getResourceAsStream(),
but may do it any way it wants to. This allows a
BeanContext's children to have their own set of
resources separate from the rest of the system.
Beans should call this method on their parent rather than the
associated
ClassLoader method.
I am assuming, but am not entirely sure, that if a
BeanContext cannot find a resource, its
responsibility is to call the
getResourceAsStream
method of its parent
BeanContext.
resourceName - the name of the resource requested.requestor - a reference to the child requesting the resource.
- the requested resource as a stream.
instantiateChild
public Object instantiateChild(String beanName)
throws IOException,
ClassNotFoundException Instantiate a Bean using this Bean's
ClassLoader
and this
BeanContext as the parent.
This method exists mainly so that
BeanContext
implementations can perform extra actions on Beans that are
created within them.
beanName - the name of the bean to instantiate
java.beans.beancontext.BeanContext
Copyright (C) 1999 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., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 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.