Deduplicate concurrent SchemaContext loads

[yangtools.git] / yang / yang-parser-impl / src / main / java / org / opendaylight / yangtools / yang / parser / repo / SharedSchemaContextFactory.java

diff --git a/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/repo/SharedSchemaContextFactory.java b/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/repo/SharedSchemaContextFactory.java
index ea585e23c77ed9f8ffcc219e962631b67fffd48e..1dca77b39c2f9a35dd97ec6821432f1f590e70c4 100644 (file)
--- a/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/repo/SharedSchemaContextFactory.java
+++ b/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/repo/SharedSchemaContextFactory.java
@@ -24,6 +24,7 @@ import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.MoreExecutors;
+import com.google.common.util.concurrent.SettableFuture;
 import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
@@ -31,6 +32,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.concurrent.ExecutionException;
 import javax.annotation.Nonnull;
 import org.antlr.v4.runtime.ParserRuleContext;
 import org.opendaylight.yangtools.antlrv4.code.gen.YangStatementParser.StatementContext;
@@ -119,20 +121,31 @@ final class SharedSchemaContextFactory implements SchemaContextFactory {
         final ListenableFuture<SchemaContext> cf = Futures.transformAsync(sf, assembleSources,
             MoreExecutors.directExecutor());
 
-        // Populate cache when successful
+        final SettableFuture<SchemaContext> rf = SettableFuture.create();
         Futures.addCallback(cf, new FutureCallback<SchemaContext>() {
             @Override
             public void onSuccess(final SchemaContext result) {
-                cache.put(uniqueSourceIdentifiers, result);
+                // Deduplicate concurrent loads
+                final SchemaContext existing;
+                try {
+                    existing = cache.get(uniqueSourceIdentifiers, () -> result);
+                } catch (ExecutionException e) {
+                    LOG.warn("Failed to recheck result with cache, will use computed value", e);
+                    rf.set(result);
+                    return;
+                }
+
+                rf.set(existing);
             }
 
             @Override
             public void onFailure(@Nonnull final Throwable cause) {
                 LOG.debug("Failed to assemble sources", cause);
+                rf.setException(cause);
             }
         }, MoreExecutors.directExecutor());
 
-        return cf;
+        return rf;
     }
 
     private ListenableFuture<ASTSchemaSource> requestSource(final SourceIdentifier identifier) {