Hi Derrel, just (basically) one more question about the new and old virtual trees:
>>Finally, why do both qx.ui.tree.VirtualTree and qx.ui.treevirtual.TreeVirtual >>exist? Do they serve similar purposes? >qx.ui.treevirtual.TreeVirtual is the original virtual tree implementation, >based on qx.ui.table.Table which was a fairly addition to qooxdoo and has >provided >wonderful capabilities, but has shown growing pains. With 20-20 hindsight, the >new qx.ui.virtual.* widgets have been created. They're not done yet, and I >believe some capabilities of qx.ui.treevirtual.TreeVirtual do not yet exist in >qx.ui.virtual.*, but I don't know the latter well enough to tell you which >those are. Are you saying that I should use qx.ui.treevirtual.TreeVirtual for a project that will be developed within the next two months? But qx.ui.virtual.* is better designed and the old qx.ui.treevirtual.TreeVirtual will be deprecated at some point? Will the transition from qx.ui.treevirtual.TreeVirtual to qx.ui.virtual.* be easy from the user perspective (not talking about the widget developer side), or does the change involve application-wide changes? And you didn't mention qx.ui.tree.VirtualTree which I asked about. How does this relate to qx.ui.virtual.*? I might come back with more questions on the TreeVirtual, but first I need to get more familiar with the models and viewers. Thanks Ron ________________________________ From: Derrell Lipman <[email protected]> To: Ron Whittaker <[email protected]>; qooxdoo Development <[email protected]> Sent: Thursday, June 30, 2011 2:20 PM Subject: Re: [qooxdoo-devel] remote tables and TreeVirtual: looking for help On Wed, Jun 29, 2011 at 17:30, Ron Whittaker <[email protected]> wrote: Hello, >I have a few questions related to remote tables and to the TreeVirtual class. > >I have a huge tree sitting on a server, and I would like to show this tree in >a client such that only parts of it are opened as requested by the user. I >guess TreeVirtual is the right choice for this? > >After reading >http://manual.qooxdoo.org/1.4.x/pages/widget/table_remote_model.html I have >been able to show a huge remote table in the client. >But... are the members funtions _loadRowCount() ..._onRowDataLoaded() >documented anywhere except for this example page? They are documented in the API docs for qx.ui.table.model.remote, but they may not be documented as well as they should be. And is it possible to transfer only a range of columns(firstCol..lastCol) such as only rows from firstRow..lastRow are loaded in _loadRowData()? > You can adjust the maximum number of blocks that are cached (see the maxCachedBlockCount property), but not to the level of specifying specific rows. (You could, of course, extend qx.ui.table.model.remote and override various methods in your subclass. I'd be curious why you wanted such fine-grained control, however. It should, I think, be necessary.) >Now for the more difficult problems: >Can I find a similar tutorial style explanation for TreeVirtual as >http://manual.qooxdoo.org/1.4.x/pages/widget/table_remote_model.html for >qx.ui.table.model.Remote? >I have not been able to set up an example that loads a tree structure from a >remote server. Which data model should I choose for the tree? I tried to use >qx.ui.treevirtual.SimpleTreeDataModel, but this seems to request the whole >tree from the server at once. I am looking for an abstract equivalent to >qx.ui.table.model.Remote? > TreeVirtual is based on Table, as you've noted. The way it's implemented is with a very special table model (referred to as a data model in TreeVirtual) and a special cell renderer. Because of all of the tree-specific requirements of the data model, you can not simply switch it to using qx.ui.table.model.Remote, which simply doesn't know about all of those tree-specific requirements. Trees work differently than tables, however. Except in extreme cases, the number of immediate descendants of any parent is not so large that it would consume vast amounts of memory in the data model. What the TreeVirtual data model provides for you are events that you may listen for, allowing you to retrieve the children of a node only when it is actually opened. qx.ui.treevirtual.TreeVirtual offers the events "treeOpenWithContent", "treeOpenWhileEmpty", and "treeClose". You can use "treeOpenWhileEmpty" to retrieve the children of the node being opened from your server. If you have a huge amount of data for your tree, you might opt, when you receive "treeClose" events, to remove those children from your model. (If you do so, then the next time the user opens that node, it will be empty, so you would again retrieve the child from the server with no loss of functionality, but at the speed penalty of a request to the server.) Finally, why do both qx.ui.tree.VirtualTree and qx.ui.treevirtual.TreeVirtual exist? Do they serve similar purposes? > qx.ui.treevirtual.TreeVirtual is the original virtual tree implementation, based on qx.ui.table.Table which was a fairly addition to qooxdoo and has provided wonderful capabilities, but has shown growing pains. With 20-20 hindsight, the new qx.ui.virtual.* widgets have been created. They're not done yet, and I believe some capabilities of qx.ui.treevirtual.TreeVirtual do not yet exist in qx.ui.virtual.*, but I don't know the latter well enough to tell you which those are. Cheers, Derrell ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. 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