Tibor17 commented on a change in pull request #65:
URL: https://github.com/apache/maven-resolver/pull/65#discussion_r456886247
##########
File path:
maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultSyncContextFactory.java
##########
@@ -28,31 +30,59 @@
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.impl.SyncContextFactory;
import org.eclipse.aether.metadata.Metadata;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.inject.Singleton;
/**
- * A factory to create synchronization contexts. This default implementation
actually does not provide any real
- * synchronization but merely completes the repository system.
+ * A factory to create synchronization contexts. This default implementation
uses fair global locking
+ * based on {@link ReentrantReadWriteLock}. Explicit artifacts and metadata
passed are ignored.
*/
@Named
+@Singleton
public class DefaultSyncContextFactory
implements SyncContextFactory
{
+ private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(
true );
public SyncContext newInstance( RepositorySystemSession session, boolean
shared )
{
- return new DefaultSyncContext();
+ return new DefaultSyncContext( shared ? lock.readLock() :
lock.writeLock(), shared );
}
static class DefaultSyncContext
implements SyncContext
{
+ private static final Logger LOGGER = LoggerFactory.getLogger(
DefaultSyncContext.class );
+
+ private final Lock lock;
+ private final boolean shared;
+ private int lockHoldCount;
+
+ DefaultSyncContext( Lock lock, boolean shared )
+ {
+ this.lock = lock;
+ this.shared = shared;
+ }
public void acquire( Collection<? extends Artifact> artifact,
Collection<? extends Metadata> metadata )
{
+ LOGGER.trace( "Acquiring global {} lock (currently held: {})",
+ shared ? "read" : "write", lockHoldCount );
+ lock.lock();
Review comment:
@michael-o
@cstamas
One way or another this code cannot be like this. If we showed this to the
Oracle guys especially from the Java Concurrency group, they would say that
this is dangerous code.
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