<Swing Dev> 7189299 DefaultButtonModel instance keeps stale listeners of JButton in case of multiple SwingUtilities.updateComponentTreeUI() calls
Alexander Scherbatiy
alexandr.scherbatiy at oracle.com
Thu Feb 7 12:06:57 UTC 2013
The fix looks good for me.
Thanks,
Alexandr.
On 1/29/2013 9:31 AM, Frank Ding wrote:
> Hi Alexandr,
> Please review my 9th attempt @
> http://cr.openjdk.java.net/~dingxmin/7189299/webrev.09/
> The revision also passed test LoadingWebPageToJEditorPane.
>
> Thanks && Best regards,
> Frank
>
> On 1/28/2013 5:04 PM, Frank Ding wrote:
>> Hi Alexandr,
>> Thanks for your suggestion. I will prepare a patch according to it
>> soon.
>>
>> Best regards,
>> Frank
>>
>> On 1/21/2013 9:41 PM, Alexander Scherbatiy wrote:
>>> On 1/18/2013 10:50 AM, Frank Ding wrote:
>>>> Hi Alexandr,
>>>> Do you have any idea?
>>>
>>> What about one more way removing listeners:
>>> - disadvantage: listeners are hardcoded
>>> - advantage: there is no need to override JButton, JList,...
>>> classes
>>>
>>> ------------------------------------------
>>> private void clearModel(Object model) {
>>> if (model instanceof DefaultButtonModel) {
>>> DefaultButtonModel buttonModel = (DefaultButtonModel)
>>> model;
>>> String listenerClass =
>>> "javax.swing.AbstractButton$Handler";
>>>
>>> for (ActionListener listener :
>>> buttonModel.getActionListeners()) {
>>> if
>>> (listenerClass.equals(listener.getClass().getName())) {
>>> buttonModel.removeActionListener(listener);
>>> }
>>> }
>>> // remove change listeners
>>> // remove item listeners
>>>
>>> } else if(model instanceof ListModel){
>>> // remove list listeners
>>> }
>>> }
>>> ------------------------------------------
>>>
>>> Thanks,
>>> Alexandr.
>>>
>>>>
>>>> Best regards,
>>>> Frank
>>>>
>>>> On 12/28/2012 11:16 AM, Frank Ding wrote:
>>>>> Hi Alexandr,
>>>>> I did some more investigations.
>>>>> 1. The model can be accessed as below which is also illustrated
>>>>> in the jtreg test
>>>>> http://cr.openjdk.java.net/~dingxmin/7189299/webrev.07/test/javax/swing/text/html/7189299/bug7189299.java.html
>>>>>
>>>>>
>>>>> HTMLEditorKit htmlEditorKit = (HTMLEditorKit) html.getEditorKit();
>>>>> StyleContext.NamedStyle style = ((StyleContext.NamedStyle)
>>>>> htmlEditorKit.getInputAttributes());
>>>>> DefaultButtonModel model = ((DefaultButtonModel)
>>>>> style.getAttribute(StyleConstants.ModelAttribute));
>>>>>
>>>>> Though it needs type conversion, model can be exposed to client
>>>>> code. This implies client code has the chance to add listeners.
>>>>> Another way of updating listener in model is by first getting
>>>>> JButton or other html Swing components and then call listener
>>>>> related api that affects model. I dumped vars above but did not
>>>>> find out possibility for application to get Swing component
>>>>> reference.
>>>>>
>>>>> 2. As of swing.text.html library, I searched 'ModelAttribute'
>>>>> under javax/swing directory with command "grep -R 'ModelAttribute'
>>>>> ." which shows aside from FormView and StyleConstants, the classes
>>>>> referencing it are HTMLDocument, HTMLWriter. This means only
>>>>> FormView adds listeners to model.
>>>>>
>>>>> My first attempt at fixing the problem (only for JButton
>>>>> listener leak) is trying to remove all listeners completely. See
>>>>> http://cr.openjdk.java.net/~dingxmin/7189299/webrev.01/. Pavel
>>>>> argued that it may cause existing application to malfunction. Then
>>>>> I came up with
>>>>> http://cr.openjdk.java.net/~dingxmin/7189299/webrev.02/ where only
>>>>> stale listeners are identified and removed using reflection. But
>>>>> Pavel insisted reflection should be prohibited. So I tried to
>>>>> work around it by extending JButton in FormView to access the
>>>>> private listener instance such that only stale listener is
>>>>> removed. The perfect revision is
>>>>> http://cr.openjdk.java.net/~dingxmin/7189299/webrev.07/.
>>>>>
>>>>> I propose we fix JButton issue as it leads to NPE visible to
>>>>> application. Bug in other components can be put off if Swing team
>>>>> intend to fix it elegantly or duplicate code like what is in v.07.
>>>>> Any idea or comment, please let me know.
>>>>>
>>>>> Thanks and best regards,
>>>>> Frank
>>>>>
>>>>> On 12/10/2012 6:40 PM, Alexander Scherbatiy wrote:
>>>>>> On 12/6/2012 12:39 PM, Frank Ding wrote:
>>>>>>> Hi Alexandr,
>>>>>>> I did several attempts but still have hang issues somewhere.
>>>>>>> It seems the new approach of caching gui components created each
>>>>>>> time is not practical because of the threading restriction
>>>>>>> already imposed on HTMLDocument.
>>>>>>> Can we make compromise by turning to previous solution (v7 in
>>>>>>> particular) and generalize it to other gui components (which
>>>>>>> means there would be JCheckBoxWrapper, JRadioButtonWrapper,
>>>>>>
>>>>>> The issue is that models contain listeners from all previous
>>>>>> components. Models are used to store data and state of components
>>>>>> when form view is recreated.
>>>>>> FormView adds it's own listeners to components (and as result
>>>>>> to the models). Could you make a little investigation to check
>>>>>> which other listeners can the models hold?
>>>>>> Can a user adds a listener? Can listeners be added by other
>>>>>> parts of the swing.text.html library?
>>>>>>
>>>>>> If old listeners does not play role, it is possible just to
>>>>>> remove them all.
>>>>>>
>>>>>> Thanks,
>>>>>> Alexandr.
>>>>>>
>>>>>>> JPasswordFieldWrapper, JTextFieldWrapper, JListWrapper,
>>>>>>> JComboBoxWrapper, and JButtonWrapper). Or shall we fix JButton
>>>>>>> only because it causes obvious exception visible to client? I
>>>>>>> am short of ideas...
>>>>>>> http://cr.openjdk.java.net/~dingxmin/7189299/webrev.07/
>>>>>>>
>>>>>>> Best regards,
>>>>>>> Frank
>>>>>>>
>>>>>>> On 12/5/2012 2:12 PM, Frank Ding wrote:
>>>>>>>> Hi Alexandr,
>>>>>>>> I observed the same issue in my environment as well. My
>>>>>>>> proposed patch would cause severe regression issues. I am
>>>>>>>> looking into the locking issue.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Frank
>>>>>>>>
>>>>>>>> On 12/3/2012 6:53 PM, Alexander Scherbatiy wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Could you check the following sample with your latest fix? It
>>>>>>>>> just hangs on my side.
>>>>>>>>>
>>>>>>>>> - put the sample.html and the response.html files on a server
>>>>>>>>> - update path to the html files in the
>>>>>>>>> LoadingWebPageToJEditorPane class
>>>>>>>>>
>>>>>>>>> ------------- sample.html ------------
>>>>>>>>> <form name="input" action="response.html" method="get">
>>>>>>>>> Username: <input type="text" name="user">
>>>>>>>>> <input type="submit" value="Submit">
>>>>>>>>> </form>
>>>>>>>>> ------------- response.html ------------
>>>>>>>>> <html>
>>>>>>>>> <body>
>>>>>>>>> Hello World!
>>>>>>>>> </body>
>>>>>>>>> </html>
>>>>>>>>> ------------- LoadingWebPageToJEditorPane.html ------------
>>>>>>>>> import java.net.URL;
>>>>>>>>> import javax.swing.JEditorPane;
>>>>>>>>> import javax.swing.JFrame;
>>>>>>>>> import javax.swing.JScrollPane;
>>>>>>>>> import javax.swing.SwingUtilities;
>>>>>>>>>
>>>>>>>>> public class LoadingWebPageToJEditorPane {
>>>>>>>>>
>>>>>>>>> private static final String HTML_PATH =
>>>>>>>>> "http://serever/path/sample.html";
>>>>>>>>>
>>>>>>>>> public static void main(String[] a) throws Exception {
>>>>>>>>>
>>>>>>>>> SwingUtilities.invokeAndWait(new Runnable() {
>>>>>>>>>
>>>>>>>>> @Override
>>>>>>>>> public void run() {
>>>>>>>>> try {
>>>>>>>>>
>>>>>>>>> JFrame frame = new JFrame();
>>>>>>>>> frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
>>>>>>>>>
>>>>>>>>> JEditorPane editorPane = new JEditorPane();
>>>>>>>>> editorPane.setPage(new URL(HTML_PATH));
>>>>>>>>>
>>>>>>>>> frame.add(new JScrollPane(editorPane));
>>>>>>>>> frame.setSize(300, 200);
>>>>>>>>> frame.setVisible(true);
>>>>>>>>> SwingUtilities.updateComponentTreeUI(editorPane);
>>>>>>>>> } catch (Exception ex) {
>>>>>>>>> throw new RuntimeException(ex);
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>> });
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>> ---------------------------------------
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Alexandr.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On 11/28/2012 10:29 AM, Frank Ding wrote:
>>>>>>>>>> Hi Alexandr,
>>>>>>>>>> I created a new patch v8 @
>>>>>>>>>> http://cr.openjdk.java.net/~dingxmin/7189299/webrev.08/. It
>>>>>>>>>> uses the newly proposed approach mentioned in my last email.
>>>>>>>>>> Could you please help to review it again?
>>>>>>>>>>
>>>>>>>>>> The patch, of course, passed jtreg test bug7189299.java in
>>>>>>>>>> the patch. What's more, I did additional tests for
>>>>>>>>>> JComboBox, JTextField and JList in my IDE by comparing
>>>>>>>>>> listener numbers observed during debugging with/without my
>>>>>>>>>> patch. The listener numbers were doubled without the fix.
>>>>>>>>>> This proves that v8 patch works for all components. I think I
>>>>>>>>>> can write those additional tests as jtreg tests after the
>>>>>>>>>> patch passes review.
>>>>>>>>>>
>>>>>>>>>> One notable change is that I had to restrict the scope of
>>>>>>>>>> holding a write lock in DefaultStyledDocument because
>>>>>>>>>> otherwise, we cannot store the new component created in
>>>>>>>>>> FormView.createComponent(). The stack trace is pasted below
>>>>>>>>>> for reference.
>>>>>>>>>>
>>>>>>>>>> Exception in thread "main"
>>>>>>>>>> java.lang.reflect.InvocationTargetException
>>>>>>>>>> at java.awt.EventQueue.invokeAndWait(EventQueue.java:1270)
>>>>>>>>>> at
>>>>>>>>>> javax.swing.SwingUtilities.invokeAndWait(SwingUtilities.java:1350)
>>>>>>>>>>
>>>>>>>>>> at bug7189299.main(bug7189299.java:116)
>>>>>>>>>> Caused by: java.lang.IllegalStateException: Attempt to mutate
>>>>>>>>>> in notification
>>>>>>>>>> at
>>>>>>>>>> javax.swing.text.AbstractDocument.writeLock(AbstractDocument.java:1357)
>>>>>>>>>>
>>>>>>>>>> at
>>>>>>>>>> javax.swing.text.html.HTMLDocument.obtainLock(HTMLDocument.java:1708)
>>>>>>>>>>
>>>>>>>>>> at
>>>>>>>>>> javax.swing.text.html.FormView.createComponent(FormView.java:211)
>>>>>>>>>>
>>>>>>>>>> ......(omitted)......
>>>>>>>>>> at
>>>>>>>>>> javax.swing.plaf.basic.BasicTextUI$RootView.insertUpdate(BasicTextUI.java:1602)
>>>>>>>>>> at
>>>>>>>>>> javax.swing.plaf.basic.BasicTextUI$UpdateHandler.insertUpdate(BasicTextUI.java:1861)
>>>>>>>>>> at
>>>>>>>>>> javax.swing.text.AbstractDocument.fireInsertUpdate(AbstractDocument.java:201)
>>>>>>>>>>
>>>>>>>>>> at
>>>>>>>>>> javax.swing.text.DefaultStyledDocument.create(DefaultStyledDocument.java:155)
>>>>>>>>>> <------ FormView.createComponent is triggered by this call
>>>>>>>>>> which has already held the lock
>>>>>>>>>> at
>>>>>>>>>> javax.swing.text.html.HTMLDocument.create(HTMLDocument.java:469)
>>>>>>>>>> ......(omitted)......
>>>>>>>>>>
>>>>>>>>>> This change did violate what is documented in
>>>>>>>>>> AbstractDocument.writeLock that "This situation violates the
>>>>>>>>>> bean event model where order of delivery is not guaranteed
>>>>>>>>>> and all listeners should be notified before further mutations
>>>>>>>>>> are allowed. " However, without the change of shrinking lock
>>>>>>>>>> scope, the component cannot be saved once it is created in
>>>>>>>>>> FormView.createComponent(). I found it is even harder to save
>>>>>>>>>> it later in code but perhaps there does exist a more
>>>>>>>>>> appropriate place to do this. If you have any better
>>>>>>>>>> suggestion, I am glad to know.
>>>>>>>>>>
>>>>>>>>>> Also I searched references to
>>>>>>>>>> 'StyleConstants.ComponentAttribute' as you asked. The result
>>>>>>>>>> is listed below. Note that the command 'grep' is invoked
>>>>>>>>>> under openjdk 8 top directory.
>>>>>>>>>> $ grep -R 'ComponentAttribute' .
>>>>>>>>>> ./jdk/src/share/classes/javax/swing/text/StyleConstants.java:
>>>>>>>>>> public static final Object ComponentAttribute = new
>>>>>>>>>> CharacterConstants("component");
>>>>>>>>>> ./jdk/src/share/classes/javax/swing/text/StyleConstants.java:
>>>>>>>>>> return (Component) a.getAttribute(ComponentAttribute);
>>>>>>>>>> ./jdk/src/share/classes/javax/swing/text/StyleConstants.java:
>>>>>>>>>> a.addAttribute(ComponentAttribute, c);
>>>>>>>>>> ./jdk/src/share/classes/javax/swing/text/StyleConstants.java:
>>>>>>>>>> Background, ComponentAttribute, IconAttribute,
>>>>>>>>>> ./jdk/src/share/classes/javax/swing/text/StyledEditorKit.java: set.removeAttribute(StyleConstants.ComponentAttribute);
>>>>>>>>>>
>>>>>>>>>> Binary file ./jdk/test/sun/tools/jhat/jmap.bin matches
>>>>>>>>>>
>>>>>>>>>> So ComponentAttribute is not referenced by other classes
>>>>>>>>>> except StyledEditorKit. StyleConstants exposes
>>>>>>>>>> ComponentAttribute in getComponent() and setComponent()
>>>>>>>>>> methods. References to StyleConstants.getComponent and
>>>>>>>>>> StyleConstants.setComponent are further searched in repo.
>>>>>>>>>>
>>>>>>>>>> $ grep -R 'StyleConstants.getComponent' .
>>>>>>>>>> ./jdk/src/share/classes/javax/swing/text/ComponentView.java:
>>>>>>>>>> * the element (by calling StyleConstants.getComponent). A
>>>>>>>>>> ./jdk/src/share/classes/javax/swing/text/ComponentView.java:
>>>>>>>>>> Component comp = StyleConstants.getComponent(attr);
>>>>>>>>>>
>>>>>>>>>> $ grep -R 'StyleConstants.setComponent' .
>>>>>>>>>> ./jdk/src/share/classes/javax/swing/JTextPane.java:
>>>>>>>>>> StyleConstants.setComponent(inputAttributes, c);
>>>>>>>>>>
>>>>>>>>>> From the facts above, I think we are sufficiently confident
>>>>>>>>>> to use ComponentAttribute.
>>>>>>>>>>
>>>>>>>>>> Please let me know if you have any comments and I can do more
>>>>>>>>>> regression tests and provide more jtreg test cases as next step.
>>>>>>>>>>
>>>>>>>>>> Thanks and regards,
>>>>>>>>>> Frank
>>>>>>>>>>
>>>>>>>>>> On 11/15/2012 5:18 PM, Alexander Scherbatiy wrote:
>>>>>>>>>>> On 11/14/2012 10:22 AM, Frank Ding wrote:
>>>>>>>>>>>> Hi Alexandr,
>>>>>>>>>>>> After a couple of hours investigating the possibility of
>>>>>>>>>>>> fixing JComboBox.setModel(null) and
>>>>>>>>>>>> JTextComponent.setComponent(null), I found that
>>>>>>>>>>>> 1. In JComboBox.setModel, the new model, null in this case,
>>>>>>>>>>>> is eventually passed to BasicComboPopup.propertyChange
>>>>>>>>>>>> where JList.setModel is called. JList.setModel rejects the
>>>>>>>>>>>> null model because of its api restriction. Below I listed
>>>>>>>>>>>> the offending call stacks in my IDE. This makes sense as
>>>>>>>>>>>> the associated drop down JList needs new model. However, it
>>>>>>>>>>>> makes fixing JComboBox.setModel(null) hard or impossible.
>>>>>>>>>>>> Exception in thread "main"
>>>>>>>>>>>> java.lang.IllegalArgumentException: model must be non null
>>>>>>>>>>>> at javax.swing.JList.setModel(JList.java:1674)
>>>>>>>>>>>> at
>>>>>>>>>>>> javax.swing.plaf.basic.BasicComboPopup$Handler.propertyChange(BasicComboPopup.java:939)
>>>>>>>>>>>> at
>>>>>>>>>>>> java.beans.PropertyChangeSupport.fire(PropertyChangeSupport.java:335)
>>>>>>>>>>>>
>>>>>>>>>>>> at
>>>>>>>>>>>> java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:327)
>>>>>>>>>>>> at
>>>>>>>>>>>> java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:263)
>>>>>>>>>>>> at
>>>>>>>>>>>> java.awt.Component.firePropertyChange(Component.java:8413)
>>>>>>>>>>>> at javax.swing.JComboBox.setModel(JComboBox.java:322)
>>>>>>>>>>>>
>>>>>>>>>>>> 2. JTextComponent.setComponent(null) can be fixed but code
>>>>>>>>>>>> change in BasicTextUI is also required.
>>>>>>>>>>>>
>>>>>>>>>>>> Since setting null model to JComboBox, JList and
>>>>>>>>>>>> JTextComponent is impossible or dangerous, just as you
>>>>>>>>>>>> mentioned, we could set a non null new model to these UI
>>>>>>>>>>>> components just for the purpose of having the side effect
>>>>>>>>>>>> of removing listeners from old model. Are you ok with this
>>>>>>>>>>>> approach?
>>>>>>>>>>> Yes. Please, try this and run the html swing automated
>>>>>>>>>>> tests from the test/javax/swing/text/html diroctory to check
>>>>>>>>>>> possible regressions.
>>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>> Alexandr.
>>>>>>>>>>>
>>>>>>>>>>>> By the way, I will investigate your another question "Could
>>>>>>>>>>>> you also check that the StyleConstants.ComponentAttribute
>>>>>>>>>>>> property value can't be rewritten by the JDK code or by
>>>>>>>>>>>> public methods." and reply soon.
>>>>>>>>>>>>
>>>>>>>>>>>> Best regards,
>>>>>>>>>>>> Frank
>>>>>>>>>>>>
>>>>>>>>>>>> On 11/13/2012 7:49 PM, Alexander Scherbatiy wrote:
>>>>>>>>>>>>> On 11/13/2012 11:53 AM, Frank Ding wrote:
>>>>>>>>>>>>>> Hi Alexandr,
>>>>>>>>>>>>>> As for your comment "Could you create an issue that a
>>>>>>>>>>>>>> JComboBox.setModel(null) call throws NPE? You could fix
>>>>>>>>>>>>>> it before the 7189299 issue. ", I created a bug with
>>>>>>>>>>>>>> internal review ID of 2381499 on
>>>>>>>>>>>>>> JComboBox.setModel(null). But test shows that
>>>>>>>>>>>>>> JPasswordField.setDocument(null),
>>>>>>>>>>>>>> JTextField.setDocument(null), JList.setModel(null) and
>>>>>>>>>>>>>> JTextArea.setDocument(null) all throw NPE. Particularly,
>>>>>>>>>>>>>> JList.setModel(null) has null check and throws
>>>>>>>>>>>>>> IllegalArgumentException("model" must be non null").
>>>>>>>>>>>>>> Shall I include those components as well?
>>>>>>>>>>>>>
>>>>>>>>>>>>> There is the javadoc for the JList setModel() method:
>>>>>>>>>>>>> Throws IllegalArgumentException - if model is null. So it
>>>>>>>>>>>>> is undesirable to change the public API.
>>>>>>>>>>>>> However, it is possible to set a new empty model for
>>>>>>>>>>>>> the JList. The list listeners should be removed from the
>>>>>>>>>>>>> old model in this case.
>>>>>>>>>>>>>
>>>>>>>>>>>>> You could have only 2 issues: one for components that
>>>>>>>>>>>>> allow to set a null model but throws NPE (like JComboBox)
>>>>>>>>>>>>> and another for components that does not allow to set null
>>>>>>>>>>>>> model but they do not remove listeners from the old model
>>>>>>>>>>>>> in case if a new model is set.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>> Alexandr.
>>>>>>>>>>>>>
>>>>>>>>>>>>>> Thanks for your guidance in advance.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Best regards,
>>>>>>>>>>>>>> Frank
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On 11/8/2012 10:55 PM, Alexander Scherbatiy wrote:
>>>>>>>>>>>>>>> On 11/7/2012 10:56 AM, Frank Ding wrote:
>>>>>>>>>>>>>>>> Hi Alexandr,
>>>>>>>>>>>>>>>> Unfortunately, all the JComponents involved in
>>>>>>>>>>>>>>>> FormView.createComponent() have bugs!
>>>>>>>>>>>>>>>> I have done tests for all other swing components,
>>>>>>>>>>>>>>>> i.e. JCheckBox, JRadioButton, JPasswordField,
>>>>>>>>>>>>>>>> JTextField, JList, JComboBox and JTextField. Sadder
>>>>>>>>>>>>>>>> news is that if we fix all components in the same way
>>>>>>>>>>>>>>>> as I did for JButton, we need to subclass them all,
>>>>>>>>>>>>>>>> resulting in JCheckBoxWrapper, JRadioButtonWrapper,
>>>>>>>>>>>>>>>> JPasswordFieldWrapper, JTextFieldWrapper, JListWrapper,
>>>>>>>>>>>>>>>> JComboBoxWrapper, JTextFieldWrapper plus
>>>>>>>>>>>>>>>> JButtonWrapper! This approach becomes unacceptable
>>>>>>>>>>>>>>>> when all swing components are affected.
>>>>>>>>>>>>>>>> Shall we fix it in other way illustrated below?
>>>>>>>>>>>>>>>> 1. Whenever a swing component is created, it is kept in
>>>>>>>>>>>>>>>> AttributeSet, as what is now for model.
>>>>>>>>>>>>>>>> 2. In FormView.createComponent(), the old swing
>>>>>>>>>>>>>>>> component can be retrieved via
>>>>>>>>>>>>>>>> attr.getAttribute(StyleConstants.ComponentAttribute).
>>>>>>>>>>>>>>>> Note that ComponentAttribute is newly added.
>>>>>>>>>>>>>>> This way should be carefully investigated that it
>>>>>>>>>>>>>>> does not introduce new memory leaks.
>>>>>>>>>>>>>>> Could you also check that the
>>>>>>>>>>>>>>> StyleConstants.ComponentAttribute property value can't
>>>>>>>>>>>>>>> be rewritten by the JDK code or by public methods.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> 3. Before setting shared model to a newly initialized
>>>>>>>>>>>>>>>> swing component, call oldComp.setModel(null),
>>>>>>>>>>>>>>>> delegating deregistration to setModel method.
>>>>>>>>>>>>>>>> 4. Seems some setModel such as
>>>>>>>>>>>>>>>> AbstractButton.setModel() can function well when the
>>>>>>>>>>>>>>>> param, new model, is null while JComboBox.setModel()
>>>>>>>>>>>>>>>> will throw NPE in case of null param.
>>>>>>>>>>>>>>> Could you create an issue that a
>>>>>>>>>>>>>>> JComboBox.setModel(null) call throws NPE? You could fix
>>>>>>>>>>>>>>> it before the 7189299 issue.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>> Alexandr.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> 5. Add null check code in those problematic setModel or
>>>>>>>>>>>>>>>> setDocument methods.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Any idea is appreciated. Thanks.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Best regards,
>>>>>>>>>>>>>>>> Frank
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> On 11/6/2012 9:26 PM, Alexander Scherbatiy wrote:
>>>>>>>>>>>>>>>>> On 11/5/2012 11:20 AM, Frank Ding wrote:
>>>>>>>>>>>>>>>>>> Hi Alexander,
>>>>>>>>>>>>>>>>>> Based on your comments last time, I refined my
>>>>>>>>>>>>>>>>>> patch of v6 and offered v7 @
>>>>>>>>>>>>>>>>>> http://cr.openjdk.java.net/~dingxmin/7189299/webrev.07/
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> This version of the fix looks good for me.
>>>>>>>>>>>>>>>>> It seems that it is the only good way to check
>>>>>>>>>>>>>>>>> that a button model contains AbstarctButton.Handler
>>>>>>>>>>>>>>>>> listener.
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Could you also check that others models used in
>>>>>>>>>>>>>>>>> the createComponent() method do not have such memory
>>>>>>>>>>>>>>>>> leaks (even the NPE is not thrown)?
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> 4. Could you add the check that the action
>>>>>>>>>>>>>>>>>> listener is invoked only once after a component tree
>>>>>>>>>>>>>>>>>> updating and the action does the same that it does
>>>>>>>>>>>>>>>>>> before a component tree updating?
>>>>>>>>>>>>>>>>>> Answer: I am afraid I could not make it in the
>>>>>>>>>>>>>>>>>> auto test (bug7189299.java) but I can achieve it to
>>>>>>>>>>>>>>>>>> some degree in manual test FormSubmit, the one you
>>>>>>>>>>>>>>>>>> illustrated below.
>>>>>>>>>>>>>>>>>> My idea of checking it in FormSubmit.java is
>>>>>>>>>>>>>>>>>> subclassing JEditorPane and overriding 'public
>>>>>>>>>>>>>>>>>> EditorKit getEditorKit()' where stack traces can be
>>>>>>>>>>>>>>>>>> examined in the overridden method to make sure
>>>>>>>>>>>>>>>>>> FormView.submitData occurs only once. This approach
>>>>>>>>>>>>>>>>>> works because FormView.submitData() calls
>>>>>>>>>>>>>>>>>> JEditorPane.getEditorKit but is tricky. However, it's
>>>>>>>>>>>>>>>>>> the only way I can think of without any additional
>>>>>>>>>>>>>>>>>> framework support. If you are in favor of adding the
>>>>>>>>>>>>>>>>>> check in FormSubmit.java, I am willing to do that.
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> At least a separated manual test can be added
>>>>>>>>>>>>>>>>> that asks a user to put a response.html file to a
>>>>>>>>>>>>>>>>> server and according to the server url checks that
>>>>>>>>>>>>>>>>> JTeditor pane show the response text after a button
>>>>>>>>>>>>>>>>> pressing.
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> html = new JEditorPane("text/html",
>>>>>>>>>>>>>>>>> "<html><body><form action=\"" + userURL + "\">"
>>>>>>>>>>>>>>>>> + "<input type=submit
>>>>>>>>>>>>>>>>> name=submit value=\"submit\"/>"
>>>>>>>>>>>>>>>>> + "</form></body></html>");
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> response.html:
>>>>>>>>>>>>>>>>> <html> <body> Hello World! </body> </html>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>>> Alexandr.
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Thanks again for all your comments and your
>>>>>>>>>>>>>>>>>> support. Once again, if you have any further concern
>>>>>>>>>>>>>>>>>> or comment, please don't hesitate to let me know.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Best regards,
>>>>>>>>>>>>>>>>>> Frank
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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