Library

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

A particular type of programmatically defined libraries is Predefined Libraries.

Accessing Libraries and Jars

Package com.intellij.openapi.roots.libraries provides functionality for working with project libraries and JAR files.

Getting 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.

Getting 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.getLibraryTable(), whereas the list of project-level library tables is accessed via LibraryTablesRegistrar.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 API from OrderEntryUtil:

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

Getting 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)) {
  roots.append(each).append("\n");
}
Messages.showInfoMessage(roots.toString(), "Library Info");

Creating a Library

To create a library, 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 project_model code sample.

Adding Contents or Modifying a Library

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().

Adding 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 project_model to see how the method mentioned above can be applied.

More details on libraries can be found in the plugin_model 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.

Last modified: 26 September 2022