NetBeans Architecture Answers for Execution API module

General Information

Question (arch-what): What is this project good for?
Answer: The IDE uses a small interface to describe the execution of Java-based classes together with arguments. The ExecutionAPI controls the execution of user-level classes. The system may have several different types of executors simultaneously installed. By default we provide so called External Execution for running a user code by an external process and Internal Execution for running the user code in the same virtual machine as the IDE.
Question (arch-overall): Describe the overall architecture.
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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?
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Question (arch-time): What are the time estimates of the work?
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Question (arch-quality): How will the quality of your code be tested and how are future regressions going to be prevented?
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Question (arch-where): Where one can find sources for your module?
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Project and platform dependencies

Question (dep-nb): What other NetBeans projects and modules does this one depend on?
Answer: WindowSystemAPI

The default answer to this question is:


These modules are required in project.xml:

• FilesystemsAPI - The module is needed for compilation. The module is used during runtime. Specification version 9.0 is required.
• InputOutputAPI - The module is needed for compilation. The module is used during runtime. Specification version 1.0 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: Execution does not depend on any external library.
Question (dep-platform): On which platforms does your module run? Does it run in the same way on each?
Answer: For running with so called external execution the java process is spawned. The module tries to find the java executable. It uses the same executable as the whole NetBeans IDE.
Question (dep-jre): Which version of JRE do you need (1.2, 1.3, 1.4, etc.)?
Answer: 1.3.
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: The module creates openide-execution.jar and core-execution.jar. Both of them are autoload modules. The openide-execution.jar contains the public APIs and the core-execution.jar contains private implementation.
Question (deploy-nbm): Can you deploy an NBM via the Update Center?
Answer: Yes.
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: No answer
Question (deploy-packages): Are packages of your module made inaccessible by not declaring them public?
Answer: core-execution.jar does not define any public packages. So the public classes in this jar are made inaccessible by the NetBeans module system. openide-execution.jar contains publicly accessible classes (no protection by the module system needed in this case).
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)?
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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. It uses the settings API to store its settings.
Question (compat-deprecation): How the introduction of your project influences functionality provided by previous version of the product?
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Access to resources

Question (resources-file): Does your module use java.io.File directly?
Answer: Yes. It uses java.io.File representing items on classpath (NbClassPath).
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: Yes. It provides its own layer. It creates menu items, services, templates and window system components.
Question (resources-read): Does your module read any resources from layers? For what purpose?
Answer: No answer
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 ?
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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:
• ClassLoader.class
• ServiceType.Registry.class
• ExecutionEngine.class
• ScriptType.class
Question (lookup-register): Do you register anything into lookup for other code to find?
Answer: In META-INF/services:
• java.net.URLStreamHandlerFactory
• org.openide.execution.ExecutionEngine
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: Following is the list of properties used by the Execution module Env-foo java.home jdk.home java.class.path sun.boot.class.path java.ext.dirs line.separator
Question (exec-component): Is execution of your code influenced by any (string) property of any of your components?
Answer: File attributes accessible via calls to org.openide.filesystems.FileObject.getAttribute(name) org.openide.filesystems.FileObject.setAttribute(name, value) They can also be stored in the module layer. Please see filesystems for more information about this. NetBeansAttrExecutor NetBeansAttrArguments readOnlyAttrs
Question (exec-ant-tasks): Do you define or register any ant tasks that other can use?
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Question (exec-classloader): Does your code create its own class loader(s)?
Answer: Yes --- this module creates its own class loader. NbClassLoader is in the public API and it is a class loader which is capable of loading classes from the Repository (a user defined dynamic class path).
Question (exec-reflection): Does your code use Java Reflection to execute other code?
Answer: Hack to close windows belonging to a thread group uses method javax.swing.SwingUtilities.getSharedOwnerFrame.
The field java.security.AccessControlContext.context is accessed due to some JDK 1.2.1 hack in org.netbeans.core.execution.AccController.
When you want to execute some object it is first compiled.
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?
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Question (exec-introspection): Does your module use any kind of runtime type information (instanceof, work with java.lang.Class, etc.)?
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Question (exec-threading): What threading models, if any, does your module adhere to? How the project behaves with respect to threading?
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Question (security-policy): Does your functionality require modifications to the standard policy file?
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Question (security-grant): Does your code grant additional rights to some other code?
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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: No answer
Question (format-dnd): Which protocols (if any) does your code understand during Drag & Drop?
Answer: None.
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: None.

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: Yes. It runs a dialog prompting the user to shut down the external processes.
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: The code should scale linarly with number of running processes.
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: The module executes external processes. It does not block the AWT thread.
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!