NetBeans 平台重新打开关闭的项目 StackOverflowError

Question

我正在编写一个基于 NetBeans 平台 (7.4) 的应用程序，并且我已经创建了一个自定义的 ProjecType 和 FileType。 ProjectType 有一个弱文件更改侦听器，用于侦听项目文件夹中放置的新文件。问题是，如果我打开一个项目，关闭它然后再次尝试重新打开它，它会耗尽内存并抛出 Mutex 异常：

Blockquote java.lang.IllegalStateException: Should not acquire Children.MUTEX while holding ProjectManager.mutex

或 IllegalStateException：

Blockquote java.lang.IllegalStateException: at org.openide.nodes.Node.assignTo(Node.java:354) at org.openide.nodes.EntrySupportDefault.justComputeNodes(EntrySupportDefault.java:212) at org.openide.nodes.ChildrenArray.nodes(ChildrenArray.java:88) at org.openide.nodes.EntrySupportDefault.getNodes(EntrySupportDefault.java:130) at org.openide.nodes.EntrySupportDefault.getNodes(EntrySupportDefault.java:172) at org.openide.nodes.Children.getNodes(Children.java:469)

另一个有趣的事情是，如果我关闭项目并对项目文件夹进行任何小的更改，例如将其移动到新位置，或者甚至只是打开该文件夹中的文件，当我尝试重新加载它时工作正常。我已经尝试完全删除弱文件侦听器但没有成功。而且我知道这不是文件更改侦听器问题，因为 Windows 不会阻止我操作项目文件夹中的文件。下面是我的 ProjectNodeFactory，它为项目文件夹中的每个可识别文件类型创建子节点。

public class MyProjectNodeFactory extends ChildFactory<FileObject> implements FileChangeListener {

private final FileObject projectFolder;

public MyProjectNodeFactory(MyProjectNode project) {
    this.projectFolder = project.getProjectDirectory();                 
    project.addFileChangeListener(this);
    refresh(true);
}

@Override
protected boolean createKeys(List<FileObject> list) {

    for (FileObject fileObject : Collections.list(projectFolder.getData(false)))
    {
        if (fileObject.getExt().equals(Bundle.MY_FILETYPE_EXTENSION())) {
            list.add(fileObject);
        }
    }
    return true;
}

@Override
protected Node[] createNodesForKey(FileObject key) {
    ArrayList<Node> nodes = new ArrayList<Node>();
    // Add data files                            
    try {
        if(key.getExt().equals(Bundle.MY_FYLETYPE_EXTENSION()))
        {   
            nodes.add(DataObject.find(key).getNodeDelegate());                
        }
    } catch (DataObjectNotFoundException ex) {
        Exceptions.printStackTrace(ex);                
    }                            
    return (nodes.toArray(new Node[nodes.size()]));
}

另外还有我的 ProjecType LogicalView 和 ProjectNode

public class MyProjectType implements Project {

private final FileObject projectDir;
private final ProjectState state;
private FileChangeListener fileChangeListener;
private Lookup lkp;

MyProjectType(FileObject dir, ProjectState state) {
    this.projectDir = dir;
    this.state = state;
}

@Override
public FileObject getProjectDirectory() {
    return projectDir;
}

@Override
public Lookup getLookup() {
    if (lkp == null) {
        lkp = Lookups.fixed(new Object[]{
            // register your features here
            this,
            new MyProjectInfo(),
            new MyProjectLogicalView(this),});
    }
    return lkp;
}

public void addFileChangeListener(FileChangeListener regularFileChangeListener) {
    this.fileChangeListener = (FileChangeListener)WeakListeners.create(FileChangeListener.class, regularFileChangeListener, this.projectDir.getPath());        
    this.projectDir.addFileChangeListener(fileChangeListener);
}

public void removeFileChangeListeners() {
    if(fileChangeListener!=null)
        this.projectDir.removeFileChangeListener(fileChangeListener);
}

private final class MyProjectInfo implements ProjectInformation {

    @StaticResource()
    public static final String PROJECT_ICON = "projectIcon.png";

   ..................

}

class MyProjectLogicalView implements LogicalViewProvider {

    @StaticResource()
    public static final String PROJECT_ICON = "projectIcon.png";

    private final MyProjectType project;

    public MyProjectLogicalView(MyProjectType project) {
        this.project = project;       
    }

    @Override
    public Node createLogicalView() {
        try {
            FileObject projectDirectory = project.getProjectDirectory();
            DataFolder projectFolder = DataFolder.findFolder(projectDirectory);
            Node nodeOfProjectFolder = projectFolder.getNodeDelegate();

            return new ProjectNode(nodeOfProjectFolder, project);
        } catch (DataObjectNotFoundException donfe) {
            Exceptions.printStackTrace(donfe);
            return new AbstractNode(Children.LEAF);
        }
    }

    private final class ProjectNode extends FilterNode {

        final MyProjectType project;

        public ProjectNode(Node node, MyProjectType project)
                throws DataObjectNotFoundException {
            super(node,
                    Children.create(new MyProjectNodeFactory(project),true),
                    new ProxyLookup(
                            new Lookup[]{
                                Lookups.singleton(project),
                                node.getLookup()
                            }));
            this.project = project;
        }

        @Override
        public Action[] getActions(boolean arg0) {
            return new Action[]{
                CommonProjectActions.newFileAction(),
                CommonProjectActions.copyProjectAction(),
                CommonProjectActions.deleteProjectAction(),
                CommonProjectActions.closeProjectAction()
            };
        }

       ...............
    }

}

Answer 1

经过大量谷歌搜索和调试后，我无法检测到为什么会发生这种内存泄漏，但我确实在下面 link 找到了解决方案，这可能对其他人有用运行进入同一个问题。 Solution to Open/Close/Re-Open a NetBeans Platform ProjectType

解决方案是获取子节点的克隆，而不仅仅是委托。

public Node node(FileObject key) {
    DataFolder folder = DataFolder.findFolder(key);
    return folder.getNodeDelegate().cloneNode();
}

我仍然不明白为什么 getNodeDelegate() 是不够的，但我假设当项目第一次关闭时，一些引用没有被释放，并且在重新打开时遇到问题。通过获取克隆，它创建了一个没有这些问题的全新父节点。我希望这对某人有所帮助，因为我很难找到解决方案。

NetBeans 平台重新打开关闭的项目 StackOverflowError

NetBeans Platform Re-Open Closed Project StackOverflowError

project-types

netbeans-platform