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NetBeans Architecture Answers for Settings module

WARNING: answering questions version 1.12 rather than the current 1.25.

Interfaces table

Group of java interfaces
Interface NameIn/OutStabilitySpecified in What Document?
SettingsAPIExportedOfficialhttp://www.netbeans.org/download/dev/javadoc/OpenAPIs/org/openide/doc-files/services-api.html#settings

ServicesAPIExportedOfficialhttp://www.netbeans.org/download/dev/javadoc/OpenAPIs/org/openide/doc-files/services-api.html#create

OptionsAPIExportedOfficialhttp://www.netbeans.org/download/dev/javadoc/OpenAPIs/org/openide/options/doc-files/api.html

XmlSettingsPersistenceExportedOfficialhttp://www.netbeans.org/download/dev/javadoc/SettingsAPI/org/netbeans/spi/settings/doc-files/api.html

FilesystemsAPIImportedOfficialhttp://www.netbeans.org/download/dev/javadoc/OpenAPIs/org/openide/filesystems/doc-files/api.html

LoadersAPIImportedOfficialhttp://www.netbeans.org/download/dev/javadoc/LoadersAPI/org/openide/loaders/doc-files/api.html

UtilitiesAPIImportedOfficialhttp://www.netbeans.org/download/dev/javadoc/OpenAPIs/org/openide/util/doc-files/api.html

NodesAPIImportedOfficialhttp://www.netbeans.org/download/dev/javadoc/OpenAPIs/org/openide/nodes/doc-files/api.html

ModulesAPIImportedOfficialhttp://www.netbeans.org/download/dev/javadoc/OpenAPIs/org/openide/modules/doc-files/api.html

Group of property interfaces
Interface NameIn/OutStabilitySpecified in What Document?
org.openide.util.SharedClassObject.initializeImportedPrivate

SystemOption needs to know whether the SharedClassObject is just performing initialization and this is done using this.getProperty ("org.openide.util.SharedClassObject.initialize") which returns null if initialize is not called and Boolean.TRUE if it is.

Group of dtd interfaces
Interface NameIn/OutStabilitySpecified in What Document?
sessionsettings-1_0.dtdExportedStablehttp://www.netbeans.org/dtds/sessionsettings-1_0.dtd

-//NetBeans//DTD Session settings 1.0//EN

properties-1_0.dtdExportedUnder Developmenthttp://www.netbeans.org/dtds/properties-1_0.dtd

-//NetBeans org.netbeans.modules.settings.examples//DTD XML ProxySettings 1.0//EN

Group of layer interfaces
Interface NameIn/OutStabilitySpecified in What Document?
RuntimeInstancesRegistryExportedOfficialhttp://www.netbeans.org/download/dev/javadoc/SettingsAPI/org/netbeans/spi/settings/doc-files/api.html#use-memory

xml/memory: Associates runtime instance with environment provider.

ServicesDisplayRegistryExportedOfficialhttp://www.netbeans.org/download/dev/javadoc/OpenAPIs/org/openide/doc-files/services-api.html#service-mirroring

UI/Services: The root folder for displaying options.


General Information

    Question (arch-what): What is this project good for?

    Answer: Settings are persistent objects with a set of properties, that should be available via lookup. Properties are expected to be changed. Implementation of setting doesn't care about persistence issues, which is responsibility of settings infrastructure. XML persistence support is provided in a standalone autoload module core-settings.jar. But a typical setting is a system option, which uses serialization at the moment. Also service types must be mentioned here. Service type can be desribed as typed a named settings.

    Question (arch-overall): Describe the overall architecture.

    WARNING: Question with id="arch-overall" has not been answered!

    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?

    WARNING: Question with id="arch-usecases" has not been answered!

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

    WARNING: Question with id="arch-time" has not been answered!

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

    WARNING: Question with id="arch-quality" has not been answered!

Project and platform dependencies


Deployment

    Question (deploy-jar): Do you deploy just module JAR file(s) or other files as well?

    Answer: SystemOption and ServiceType are inside openide.jar; But the settings infrastructure is distributed between openide.jar and core.jar; Instead of SystemOption or ServiceType can be used arbitrary object , that cooperate with convertor. Infrastracture for convertos is in core-settings.jar;

    Question (deploy-nbm): Can you deploy an NBM via the Update Center?

    Answer: openide.nbm and core.nbm) are reachable via the Update Center .

    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: openide.jar and core.jar must be in the shared location as it is part of the core of NetBeans. core-settings.jar.jar can be anywhere.

    Question (deploy-packages): Are packages of your module made inaccessible by not declaring them public?

    Answer: SystemOption and ServiceType are publicly accessible. The settings infrastructure for SystemOptions resides in core.jar and is considered private except InstanceDataObject which is in openide.jar, which is public. Infrastracture for convertos is in core-settings.jar exposes some packages explicitly declaring them in manifest, which means that all other packages are inaccessible.

    Question (deploy-dependencies): What do other modules need to do to declare a dependency on this one?

    WARNING: Question with id="deploy-dependencies" has not been answered!

Compatibility with environment

    Question (compat-i18n): Is your module correctly internationalized?

    Answer: Yes

    Question (compat-standards): Does the module implement or define any standards? Is the implementation exact or does it deviate somehow?

    Answer: No

    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: Yes.

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:

    Provided layers:
    • core-settings.jar org/netbeans/modules/settings/resources/mf-layer
    • In core.jar in org/netbeans/core/resources/mf-layer.xml

    Provided folderes:

    Question (resources-read): Does your module read any resources from layers? For what purpose?

    Answer: Many times mentioned in this document. See this document.

    Question (resources-mask): Does your module mask/hide/override any resources provided by other modules in their layers?

    Answer: Yes core-settings.jar override xml/lookup/Netbeans/DTD_Session_settings_1_0.instance in core.jar and mainly its attributes. So, if is core-settings.jar present, then take over functionality of settings infrastructure implemented in core.jar.

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:
    • In InstanceDataObject.createSettingsFile is looked up ServiceType.Registry to be sure, that ServiceType is unique.
    • Also ClassLoader is looked up often to find ModuleManager.SystemClassLoader .
    • Hack for system options implemented in SharedClassObject.findObject lookes for instance of setting class in the active session to find serialized state of the option, if such state exists it is deserialized before the object is returned from lookup, then all SystemOptions are deserialized at this place the first time anybody asks for the option.

    Question (lookup-register): Do you register anything into lookup for other code to find?

    Answer: Yes. There is registered Environment.Provider which is ultimately used to provide Lookup, that provides InstanceCookie. This is a second way how can mainly InstanceDataObject call outside implementation (first one are method calls by reflection).

    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?

    Answer: Neither java system nor (System.getProperty) property. But attributes attached to FileObject are used for configuration. This configuration is too complex and can't be separated from entity registration and so on. So, here is description of configuration. org.openide.util.SharedClassObject.initialize - SystemOption needs to know whether the SharedClassObject is just performing initialization and this is done using this.getProperty ("org.openide.util.SharedClassObject.initialize") which returns null if initialize is not called and Boolean.TRUE if it is.

    Question (exec-component): Is execution of your code influenced by any (string) property of any of your components?

    Answer: No.

    Question (exec-ant-tasks): Do you define or register any ant tasks that other can use?

    WARNING: Question with id="exec-ant-tasks" has not been answered!

    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 reflection is used heavily.
    • There is used reflection to create new instance of setting. Either direcltly newInstance or factory method, that is defined in setting file.
    • Setting infrastructure registers its own PropertyChangeListener to know about changes and calls addPropertyChangeListener on setting instances. There is also called pair method removePropertChangeListener.
    • For synchronization of file name with instance name is called on setting instance method getDisplayName and getName.
    • If settings is implemented as SystemOption, then there is necessary to know if is project specific or global, to be able to reset it to default value after another project was chosen. Then there is called method isGlobal by reflection on instance of setting.
    • If XMLPropertiesConvertor is used for settings based on xml with grammar defined by -//NetBeans org.netbeans.modules.settings.examples//DTD XML ProxySettings 1.0//EN, then methods readProperties and writeProperties is used on instance of setting.

    Question (exec-privateaccess): Are you aware of any other parts of the system calling some of your methods by reflection?

    Answer: There are method invocations between parts of setting infrastructure.
    • If there is created new persistent instance of setting object in the runtime, then InstanceDataObject that comes from openide.jar, calls method responsible for storing setting on disk. This method is expected to have following decaration public void methodName (java.io.Writer w, Object inst). Which method and from which module is invoked depends on configuration.
    • If new persistent instances of setting was created, then infrastructure must be notified about it, to be able to listen on changes and ensure , that all changes will be stored. Then from InstanceDataObject is used Lookup to find InstanceCookie. Then method setInstance is invoked on instance of InstanceCookie. This binds instance of setting to setting infrastructure. Which Lookup and then also which InstanceCookie is used depends again on cofiguration. description of configuration.
    • Also org.openide.util.SharedClassObject.reset is called from org.netbeans.modules.settings.convertors.XMLSettingsSupport.SettingsRecognizer.

    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 external process.

    Question (exec-introspection): Does your module use any kind of runtime type information (instanceof, work with java.lang.Class, etc.)?

    Answer: No answer

    Question (exec-threading): What threading models, if any, does your module adhere to?

    WARNING: Question with id="exec-threading" has not been answered!

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

    WARNING: Question with id="security-policy" has not been answered!

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

    WARNING: Question with id="security-grant" has not been answered!

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:

    Question (format-dnd): Which protocols (if any) does your code understand during Drag & Drop?

    Answer: No special implementation.

    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: No special implementation.

Performance and Scalability

    Question (perf-startup): Does your module run any code on startup?

    Answer: No. Instances are provided on request, the same is true for activity of infrastructure.

    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: Not completely relevant questin in this case. There is not so much important how many settings will be defined, but how heavily will be used.

    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: Hardly to estimate.

    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. Perhaps if ToolsOption is showed, then createing of nodes defined in UI/Services may take relatively enough time, but not sure if this should be considered as part of setting infrastructure.

    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.

    Question (perf-menus): Does your module use dynamically updated context menus, or context-sensitive actions with complicated and slow enablement logic?

    Answer: No

    Question (perf-spi): How the performance of the plugged in code will be enforced?

    WARNING: Question with id="perf-spi" has not been answered!

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