Overview

# NetBeans Architecture Answers for java/api module

- Author: jglick@netbeans.org
- Answers as of: Dec 7, 2006
- Answers for questions version: 1.24
- Latest available version of questions: 1.26

WARNING: answering questions version 1.24 rather than the current 1.26.

## Interfaces table

##### Group of java interfaces

Interface Name | In/Out | Stability | Specified in What Document?
JavaSupportAPIs | Exported | Official | The Java Support APIs provides basic facilities for getting or supplying information about Java-language source files. It is based on the query pattern so implementations can be supplied from other modules or projects.
Filesystems | Imported | Official | For many purposes.
Execution | Imported | Official | `NbClassLoader` is used by `ClassPath.getClassLoader(...)`.
FilesystemsAPI | Imported | Official | .../overview-summary.html The module is needed for compilation. The module is used during runtime. Specification version 6.2 is required.
UtilitiesAPI | Imported | Official | ../org-openide-util/overview-summary.html The module is needed for compilation. The module is used during runtime. Specification version 6.2 is required.
ExecutionAPI | Imported | Official | .../overview-summary.html The module is needed for compilation. The module is used during runtime. Specification version 1.2 is required.
InputOutputAPI | Imported | Official | ../org-openide-io/overview-summary.html The module is needed for compilation. The module is used during runtime.

## General Information

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

Answer:

Models basic aspects of the metadata surrounding Java source files, such as the classpath. More information in the Javadoc.

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

Answer: JavaSupportAPIs - The Java Support APIs provides basic facilities for getting or supplying information about Java-language source files. It is based on the query pattern so implementations can be supplied from other modules or projects.

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:

The API is widely used by all sorts of IDE modules which need to work with Java sources. They can obtain the classpath or boot classpath for a file (if there is one), find out where its source root is, find sources corresponding to bytecode class files, find all sources or classpaths corresponding to open projects, find Javadoc, etc. The SPI is intended mainly for Java platform and library providers, and project type providers, to declare all of this information.

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

Answer:

Essentially done.

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

Answer:

Ought to be covered by unit tests.

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

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

## Project and platform dependencies

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

Answer:

- Filesystems -

  For many purposes.

- Execution -

  `NbClassLoader` is used by `ClassPath.getClassLoader(...)`.

Default answer to this question is:

These modules are required in project.xml file:

- FilesystemsAPI - The module is needed for compilation. The module is used during runtime. Specification version 6.2 is required.
- UtilitiesAPI - The module is needed for compilation. The module is used during runtime. Specification version 6.2 is required.
- ExecutionAPI - The module is needed for compilation. The module is used during runtime. Specification version 1.2 is required.
- InputOutputAPI - The module is needed for compilation. The module is used during runtime.

Question (dep-non-nb): What other projects outside NetBeans does this one depend on?

Answer:

None.

Question (dep-platform): On which platforms does your module run? Does it run in the same way on each?

Answer:

Any.

Question (dep-jre): Which version of JRE do you need (1.2, 1.3, 1.4, etc.)?

Answer:

1.4+.

Question (dep-jrejdk): Do you require the JDK or is the JRE enough?

Answer:

JRE.

## Deployment

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

Answer:

Just a JAR.

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:

Anywhere.

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

Answer:

Yes, only API and SPI packages are exported.

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

Answer:

       OpenIDE-Module-Module-Dependencies: org.netbeans.api.java/1 > 1.10.22

## Compatibility with environment

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

Answer:

No I18N issues.

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:

No settings.

## 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.

## 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, query implementations are found using Lookup as usual.

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?

Answer:

No.

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:

There is support for getting a class loader corresponding to a given classpath, useful e.g. for loading user JavaBeans to introspect. This is not used within the module itself.

Question (exec-reflection): Does your code use Java Reflection to execute other code?

Answer:

No.

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:

No.

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

Answer:

Currently each data structure is intended to be thread-safe.

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

Answer:

No.

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

Answer:

`ClassPath.getClassLoader(...)` is granted all permissions.

## 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:

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:

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:

Queries perform linearly in number of implementations, but as usual there will typically be only one or two implementations, e.g. delegating to owner projects.

Currently `ClassPath`s keep global file change listeners to permit roots to be invalidated, and this makes file change events linear in the number of `ClassPath` objects. This area is being studied and will hopefully be optimized, perhaps reducing overhead to a small constant. May require explicit support from the Filesystems API to fully optimize.

Question (perf-limit): Are there any hard-coded or practical limits in the number or size of elements your code can handle?

Answer:

None known.

Question (perf-mem): How much memory does your component consume? Estimate with a relation to the number of windows, etc.

Answer:

TBD, but probably little.

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.

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?

Answer:

No special provisions.

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