NetBeans Architecture Answers for Explorer & Property Sheet API module

General Information

Question (arch-what): What is this project good for?
Answer: The ExplorerAPI is build around Explorer - solely a user-interface device: it has no particular knowledge of the structure of the IDE. Rather, it provides the physical user interface for the Node hierarchy, as described in the NodesAPI. A given Explorer instance will be some visual component (such as a Swing panel) displaying some representation of a subtree of the complete Node hierarchy; the topmost node being displayed is said to be the root of the Explorer. Be careful not to confuse the root of a particular Explorer instance, which is selected according to what the user wishes to see, with the root(s) of the entire Node hierarchy, which generally are fixed.
Question (arch-overall): Describe the overall architecture.
Answer:

Provides Swing UI components that render provided node hierarchy in different ways (as a tree, list, icons, set of properties and many other).

Question (arch-usecases): Describe the main use cases of the new API. Who will use it under what circumstances? What kind of code would typically need to be written to use the module?
Answer:

For general overview of the concepts related to nodes and explorers, together with code samples, see chapter 7, of NetBeans Platform for Beginners by Jason Wexbridge and Walter Nyland.

Question (arch-time): What are the time estimates of the work?
Answer:

XXX no answer for arch-time

Question (arch-quality): How will the quality of your code be tested and how are future regressions going to be prevented?
Answer:

XXX no answer for arch-quality

Question (arch-where): Where one can find sources for your module?
Answer:

The sources for the module are in the Apache Git repositories or in the GitHub repositories

Project and platform dependencies

Question (dep-nb): What other NetBeans projects and modules does this one depend on?
Answer: The project needs Nodes API and UtilitiesAPI which are essential for it to run. Beyond that it uses runtime checks for presence of other APIs (PENDING) to use their features for backward compatibility.

The default answer to this question is:


These modules are required in project.xml:

• ETable - The module is needed for compilation. The module is used during runtime. Specification version 1.25 is required.
• TabbedContainerAPI - The module is needed for compilation. The module is used during runtime. Specification version 1.20 is required.
• org.openide.awt - The module is needed for compilation. The module is used during runtime. Specification version 7.82 is required.
• DialogsAPI - The module is needed for compilation. The module is used during runtime. Specification version 6.2 is required.
• NodesAPI - The module is needed for compilation. The module is used during runtime. Specification version 7.24 is required.
• UtilitiesAPI - The module is needed for compilation. The module is used during runtime. Specification version 9.3 is required.
• WeakListener.setAccessible - The module is needed for compilation. The module is used during runtime. Specification version 9.3 is required.
• LookupAPI - The module is needed for compilation. The module is used during runtime. Specification version 8.0 is required.
Question (dep-non-nb): What other projects outside NetBeans does this one depend on?
Answer: No other dependencies.
Question (dep-platform): On which platforms does your module run? Does it run in the same way on each?
Answer: The module is platform independent.
Question (dep-jre): Which version of JRE do you need (1.2, 1.3, 1.4, etc.)?
Answer: Runs on JDK1.3 and higher.
Question (dep-jrejdk): Do you require the JDK or is the JRE enough?
Answer: JRE is enough.

Deployment

Question (deploy-jar): Do you deploy just module JAR file(s) or other files as well?
Answer: Right now the module is part of openide.jar.
Question (deploy-nbm): Can you deploy an NBM via the Update Center?
Answer: The whole openide.jar and core.jar can be updated as nbm file.
Question (deploy-shared): Do you need to be installed in the shared location only, or in the user directory only, or can your module be installed anywhere?
Answer: As part of openide.jar it needs to be in shared location.
Question (deploy-packages): Are packages of your module made inaccessible by not declaring them public?
Answer: Both packages (org.openide.explorer and org.openide.explorer.view) are part of API, so there is no need to make them unaccessible.
Question (deploy-dependencies): What do other modules need to do to declare a dependency on this one, in addition to or instead of the normal module dependency declaration (e.g. tokens to require)?
Answer:

XXX no answer for deploy-dependencies

Compatibility with environment

Question (compat-i18n): Is your module correctly internationalized?
Answer: The module is fully internationalized.
Question (compat-standards): Does the module implement or define any standards? Is the implementation exact or does it deviate somehow?
Answer: The explorer does not implement any standards.
Question (compat-version): Can your module coexist with earlier and future versions of itself? Can you correctly read all old settings? Will future versions be able to read your current settings? Can you read or politely ignore settings stored by a future version?
Answer: The only serializable object that might be part of some settings is ExplorerManager which serialization is backward compatible.
Question (compat-deprecation): How the introduction of your project influences functionality provided by previous version of the product?
Answer:

XXX no answer for compat-deprecation

Access to resources

Question (resources-file): Does your module use java.io.File directly?
Answer: No.
Question (resources-layer): Does your module provide own layer? Does it create any files or folders in it? What it is trying to communicate by that and with which components?
Answer: No.
Question (resources-read): Does your module read any resources from layers? For what purpose?
Answer: No.
Question (resources-mask): Does your module mask/hide/override any resources provided by other modules in their layers?
Answer: No.
Question (resources-preferences): Does your module uses preferences via Preferences API? Does your module use NbPreferences or or regular JDK Preferences ? Does it read, write or both ? Does it share preferences with other modules ? If so, then why ?
Answer:

XXX no answer for resources-preferences

Lookup of components

Question (lookup-lookup): Does your module use org.openide.util.Lookup or any similar technology to find any components to communicate with? Which ones?
Answer: Yes, it does. There is searched for java.awt.datatransfer.Clipboard.class (to obtain clipboard for cut/cope/paste operations), for org.openide.actions.ActionManager (to process an action in separate thread) and for registry of all top components. A presence these object are not forced, system can work w/o them.
Question (lookup-register): Do you register anything into lookup for other code to find?
Answer: No.
Question (lookup-remove): Do you remove entries of other modules from lookup?
Answer: No.

Execution Environment

Question (exec-property): Is execution of your code influenced by any environment or Java system (System.getProperty) property? On a similar note, is there something interesting that you pass to java.util.logging.Logger? Or do you observe what others log?
Answer: netbeans.dnd.enabled - Checks by Drag & Drop support for views. True is regard as default (no matter what jdk's version). False value disallows Drag & Drop in all views. customDelete - Nodes returing Boolean.TRUE from getValue("customDelete") are assumed to provide their own confirmation dialog for delete action and explorer will not show default one when they are deleted. slowRename - Nodes returing Boolean.TRUE from getValue("slowRename") are expected to have potentially slow implemenation of setName. Explorer views rather process in-place rename in background for such nodes.
Question (exec-component): Is execution of your code influenced by any (string) property of any of your components?
Answer: org.openide.explorer.VisualizerNode.prefetchCount - Setting this property to integer number controls prefetching of nodes when VisualizerChildren are constructed (prefetchCount = 0 disables prefetching). The prefetching should eliminate "bounce" effect (see #144718) in lazy implementation which is caused by the fact that there exist keys without nodes. In such case "dummy" nodes are created and remove event is fired. This undesirable effect is eliminated by prefetching selected number of nodes so "dummy" nodes are detected and removed in advance before any visualization occurs.
Question (exec-ant-tasks): Do you define or register any ant tasks that other can use?
Answer:

XXX no answer for exec-ant-tasks

Question (exec-classloader): Does your code create its own class loader(s)?
Answer: No.
Question (exec-reflection): Does your code use Java Reflection to execute other code?
Answer: Yes, TreeView calls via reflection to openide's Window System API and to Actions API to allow use Explorer API as standalone library.
Question (exec-privateaccess): Are you aware of any other parts of the system calling some of your methods by reflection?
Answer: No.
Question (exec-process): Do you execute an external process from your module? How do you ensure that the result is the same on different platforms? Do you parse output? Do you depend on result code?
Answer: No.
Question (exec-introspection): Does your module use any kind of runtime type information (instanceof, work with java.lang.Class, etc.)?
Answer: Also TreeTableView offers sort by the values of explored properties if type of value implements Comparable interface, it's based on semi-private API TreeTableViewSortingAPI.
Question (exec-threading): What threading models, if any, does your module adhere to? How the project behaves with respect to threading?
Answer:

XXX no answer for exec-threading

Question (security-policy): Does your functionality require modifications to the standard policy file?
Answer:

XXX no answer for security-policy

Question (security-grant): Does your code grant additional rights to some other code?
Answer:

XXX no answer for security-grant

Format of files and protocols

Question (format-types): Which protocols and file formats (if any) does your module read or write on disk, or transmit or receive over the network? Do you generate an ant build script? Can it be edited and modified?
Answer: None.
Question (format-dnd): Which protocols (if any) does your code understand during Drag & Drop?
Answer: Same formats as during clipboard access.
Question (format-clipboard): Which data flavors (if any) does your code read from or insert to the clipboard (by access to clipboard on means calling methods on java.awt.datatransfer.Transferable?
Answer: The module servers as a bridge between nodes and the clipboard. It takes what Nodes provide (Node.clipboardCopy, Node.clipboardCut) and inserts them into clipboard (as part of Copy/Cut action) and also retrive the content of clipboard and pases it to Node.getPasteTypes(Transferable)) during paste action.

Performance and Scalability

Question (perf-startup): Does your module run any code on startup?
Answer: No.
Question (perf-exit): Does your module run any code on exit?
Answer: No.
Question (perf-scale): Which external criteria influence the performance of your program (size of file in editor, number of files in menu, in source directory, etc.) and how well your code scales?
Answer: No answer
Question (perf-limit): Are there any hard-coded or practical limits in the number or size of elements your code can handle?
Answer: No.
Question (perf-mem): How much memory does your component consume? Estimate with a relation to the number of windows, etc.
Answer: No answer
Question (perf-wakeup): Does any piece of your code wake up periodically and do something even when the system is otherwise idle (no user interaction)?
Answer: No.
Question (perf-progress): Does your module execute any long-running tasks?
Answer: No answer
Question (perf-huge_dialogs): Does your module contain any dialogs or wizards with a large number of GUI controls such as combo boxes, lists, trees, or text areas?
Answer: No, only the small dialogs, e.g. Rename, Navigator, etc.
Question (perf-menus): Does your module use dynamically updated context menus, or context-sensitive actions with complicated and slow enablement logic?
Answer: No answer
Question (perf-spi): How the performance of the plugged in code will be enforced?
Answer:

XXX no answer for perf-spi