Spdx-Java-Library

Spdx-Java-Library is a Java library which implements the Java object model for SPDX and provides useful helper functions.

The library is available in Maven Central as
org.spdx:java-spdx-library
(note the order of the word “java-spdx”).

If you are using Maven, you can add the following dependency in your POM file:

<dependency>
  <groupId>org.spdx</groupId>
  <artifactId>java-spdx-library</artifactId>
  <version>[2.0,3.0)</version>
</dependency>

See the GETTING-STARTED.md file for installation
instructions and how to get started in different scenarios.

Table of Contents

• Library Version Compatibility
• API Documentation
• Storage Interface
  • Storage Interface Usage
• Multi-Threaded Considerations
• Configuration Options
• Initialization
• Update for New Versions of the Spec
• Contributing

Library Version Compatibility

Library version 2.0.0 and higher is not compatible with previous versions of the library due to breaking changes introduced in SPDX 3.0.

However, the library supports both SPDX specification versions 2.X and 3.X.

See README-V3-UPGRADE.md for library upgrade instructions.

API Documentation

Here are links to the API documentation for the family of SPDX Java libraries.

“release” points to the API documentation of the latest stable version of the library, while “dev” points to the API documentation generated every time there is an update in the library’s GitHub repository.

Storage Interface

• The Spdx-Java-Library allows for different implementations of SPDX object
  storage.
• The storage facility implements the org.spdx.storage.IModelStore interface.
  This is a low level Service Provider Interface (SPI).
• The ISerializableModelStore extends the IModelStore and supports
  serializing and de-serializing the store to an I/O Stream.
  This interface is currently used to implement JSON, XML, YAML, and RDF/XML
  formats.
• The default storage interface is an in-memory Map which should be sufficient
  for lightweight usage of the library.

Storage Interface Usage

• Most common use of the library would de-serialize an existing SPDX document
  using one of the supported formats and model stores.
• To create SPDX objects from scratch, simply create the Java objects found in
  the org.spdx.library.model package.
• The model follows the SPDX Object Model.
• The model objects themselves are stateless and do not store information.
• All information is retrieved from the model store when properties are access.
• Storage to the classes will store the updates through the use of the storage
  interface.

Multi-Threaded Considerations

The methods enterCriticalSection and leaveCriticalSection are available to
support multi-threaded applications.

These methods serialize access to the model store for the specific SPDX
document used for the SPDX model object.

Configuration options

Spdx-Java-Library can be configured using either Java system properties or a Java properties file located in the runtime CLASSPATH at /resources/spdx-java-library.properties.

The library has these configuration options:

1. org.spdx.useJARLicenseInfoOnly - a boolean that controls whether the (potentially out of date) listed license information bundled inside the JAR is used (true), vs the library downloading the latest files from the SPDX website (false). Default is false (always download the latest files from the SPDX website).
2. org.spdx.downloadCacheEnabled - a boolean that enables or disables the download cache. Defaults to false (the cache is disabled). The cache location is determined as per the XDG Base Directory Specification (i.e. ${XDG_CACHE_HOME}/Spdx-Java-Library or ${HOME}/.cache/Spdx-Java-Library).
3. org.spdx.downloadCacheCheckIntervalSecs - a long that controls how often each cache entry is rechecked for staleness, in units of seconds. Defaults to 86,400 seconds (24 hours). Set to 0 (zero) to have each cache entry checked every time (note: this will result in a lot more network I/O and negatively impact performance, albeit there is still a substantial performance saving vs not using the cache at all).

Note that these configuration options can only be modified prior to first use
of Spdx-Java-Library.
Once the library is initialized, subsequent changes will have no effect.

Initialization

Before executing any of the model class methods, the model versions need to be initialized. This is done by calling:

SpdxModelFactory.init();

SPDX data is stored in a “model store” and copying between model stores requires a copy manager.

A simple store is provided in the java library. To create the simple in-memory model store and a copy manager, execute the following:

InMemSpdxStore modelStore = new InMemSpdxStore();
IModelCopyManager copyManager = new ModelCopyManager();

Many factory and helper methods in the library make use of a DefaultModelStore
if no model store or copy manager is specified.

The SpdxModelFactory.init() will create defaults for this purpose.

If you would like to use a different default model store and/or copy manager, you can call:

DefaultModelStore.initialize(IModelStore newModelStore, String newDefaultDocumentUri,
                            IModelCopyManager newDefaultCopyManager);

The newDefaultDocumentUri is a default document URI used for SPDX Spec version 2 model objects.

IMPORTANT NOTE: The call to DefaultModelStore.initialize must be made prior to or immediately after the call
to SpdxModelFactory.init(). Otherwise, any data stored in the previous default model object will be lost.
The SpdxModelFactory.init() will not overwrite an already initialized default model store.

Update for new versions of the spec

To update Spdx-Java-Library, the following is a very brief checklist:

1. Create a Java .jar file for the new version which contains an implementation of ISpdxModelInfo - typically named SpdxModelInfoVXXX - where “XXX” is the version of the spec.
2. Update the SpdxModelFactory source file to load the model info by adding the line ModelRegistry.getModelRegistry().registerModel(new SpdxModelInfoVXXX()); in the static block at the very beginning of the class.
3. If there are any conversions that are needed when copying to or from the new model version, add conversion code to the ModelCopyConverter class.
4. Update SpdxModelFactory unit test for the highest version check

Development Status

Stable.

Contributing

Reviews and suggestions are welcome.
Please submit an issue with any suggestions.

See CONTRIBUTING.md for contribution guidelines.