+ * SyncContext syncContext = repositorySystem.newSyncContext( ... );
+ * try {
+ * syncContext.acquire( artifacts, metadatas );
+ * // work with the artifacts and metadatas
+ * } finally {
+ * syncContext.close();
+ * }
+ *
+ *
+ * Within one thread, synchronization contexts may be nested which can naturally happen in a hierarchy of method calls.
+ * The nested synchronization contexts may also acquire overlapping sets of artifacts/metadatas as long as the following
+ * conditions are met. If the outer-most context holding a particular resource is exclusive, that resource can be
+ * reacquired in any nested context. If however the outer-most context is shared, the resource may only be reacquired by
+ * nested contexts if these are also shared.
+ * + * A synchronization context is meant to be utilized by only one thread and as such is not thread-safe. + *
+ * Note that the level of actual synchronization is subject to the implementation and might range from OS-wide to none. + * + * @see RepositorySystem#newSyncContext(RepositorySystemSession, boolean) + */ +public interface SyncContext + extends Closeable +{ + + /** + * Acquires synchronized access to the specified artifacts and metadatas. The invocation will potentially block + * until all requested resources can be acquired by the calling thread. Acquiring resources that are already + * acquired by this synchronization context has no effect. Please also see the class-level documentation for + * information regarding reentrancy. The method may be invoked multiple times on a synchronization context until all + * desired resources have been acquired. + * + * @param artifacts The artifacts to acquire, may be {@code null} or empty if none. + * @param metadatas The metadatas to acquire, may be {@code null} or empty if none. + */ + void acquire( Collection artifacts, Collection metadatas ); + + /** + * Releases all previously acquired artifacts/metadatas. If no resources have been acquired before or if this + * synchronization context has already been closed, this method does nothing. + */ + void close(); + +}