intellij-sdk-code-samples/reference_guide/project_model/library.md

title
Library

A library is an archive of compiled code (such as JAR files) that your modules depend on.

The IntelliJ Platform supports three types of libraries:

• Module Library: the library classes are visible only in this module and the library information is recorded in the module .iml file.
• Project Library: the library classes are visible within the project and the library information is recorded under .idea/libraries directory or in the project .ipr file.
• Global Library: the library information is recorded in the applicationLibraries.xml file in <User Home>/.IntelliJIdea/config/options directory. Global libraries are similar to project libraries, but are visible for different projects.

For more information about libraries, refer to Libraries.

A particular type of programmatically defined libraries is Predefined Libraries.

Accessing Libraries and Jars

Package libraries provides functionality for working with project libraries and jars.

How do I get a list of libraries a module depends on?

To get the list of libraries that a module depends on, use OrderEnumerator.forEachLibrary as follows.

final List<String> libraryNames = new ArrayList<String>();
ModuleRootManager.getInstance(module).orderEntries().forEachLibrary(library -> {
  libraryNames.add(library.getName());
  return true;
});
Messages.showInfoMessage(StringUtil.join(libraryNames, "\n"), "Libraries in Module");

This sample code outputs a list of libraries that the given module depends on.

How do I get a list of all libraries?

To manage the lists of application and project libraries, use LibraryTable. The list of application-level library tables is accessed by calling LibraryTablesRegistrar.getInstance().getLibraryTable(), whereas the list of project-level library tables is accessed through LibraryTablesRegistrar.getInstance().getLibraryTable(Project). Once you have a LibraryTable, you can get the libraries in it by calling LibraryTable.getLibraries().

To get the list of all module libraries defined in a given module, use the following API:

OrderEntryUtil.getModuleLibraries(ModuleRootManager.getInstance(module));

How do I get the library content?

Library provides the getUrls() method you can use to get a list of source roots and classes the library includes. To clarify, consider the following code snippet:

StringBuilder roots = new StringBuilder("The " + lib.getName() + " library includes:\n");
roots.append("Sources:\n");
for (String each : lib.getUrls(OrderRootType.SOURCES)) {
  roots.append(each).append("\n");
}
roots.append("Classes:\n");
for (String each : lib.getUrls(OrderRootType.CLASSES)) {
  strRoots.append(each).append("\n");
}
Messages.showInfoMessage(roots.toString(), "Library Info");

How do I create a library?

To create a library, you need to perform the following steps:

• Get a write action
• Obtain the library table to which you want to add the library. Use one of the following, depending on the library level:
  • LibraryTablesRegistrar.getInstance().getLibraryTable()
  • LibraryTablesRegistrar.getInstance().getLibraryTable(Project)
  • ModuleRootManager.getInstance(module).getModifiableModel().getModuleLibraryTable()
• Create the library by calling LibraryTable.createLibrary()
• Add contents to the library (see below)
• For a module-level library, commit the modifiable model returned by ModuleRootManager.getInstance(module).getModifiableModel().

For module-level libraries, you can also use simplified APIs in the ModuleRootModificationUtil class to add a library with a single API call. You can find an example of using these APIs in the sample plugin.

How do I add contents to a library or modify it?

To add or change the roots of a library, you need to perform the following steps:

• Get a write action
• Get a modifiable model for the library, using Library.getModifiableModel()
• Use methods such as Library.ModifiableModel.addRoot() to perform the necessary changes
• Commit the model using Library.ModifiableModel.commit().

How do I add a library dependency to a module?

Use ModuleRootModificationUtil.addDependency(module, library) from under a write action.

Checking Belonging to a Library

The ProjectFileIndex interface implements a number of methods you can use to check whether the specified file belongs to the project library classes or library sources. You can use the following methods:

• To check if a specified virtual file is a compiled class file use

  ProjectFileIndex.isLibraryClassFile(virtualFile)
  

• To check if a specified virtual file or directory belongs to library classes use

  ProjectFileIndex.isInLibraryClasses(virtualFileorDirectory)
  

• To check if the specified virtual file or directory belongs to library sources use

  ProjectFileIndex.isInLibrarySource(virtualFileorDirectory)
  

See the following code sample to see how the method mentioned above can be applied.

More details on libraries can be found in this code sample

Predefined Libraries

EP: com.intellij.additionalLibraryRootsProvider

AdditionalLibraryRootsProvider Allows providing synthetic/predefined libraries (SyntheticLibrary) in a project without exposing them in the model. By default, they're also hidden from UI.