Merge "Improve SnapshotBackedReadTransaction.close()"

[controller.git] / opendaylight / md-sal / sal-inmemory-datastore / src / main / java / org / opendaylight / controller / md / sal / dom / store / impl / SnapshotBackedReadTransaction.java

diff --git a/opendaylight/md-sal/sal-inmemory-datastore/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/SnapshotBackedReadTransaction.java b/opendaylight/md-sal/sal-inmemory-datastore/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/SnapshotBackedReadTransaction.java
index 2a9840634381efea5c76cfd220530a11a83d80f0..2caa76d49dff02a34ad98232ccdc7db139f07f2c 100644 (file)
--- a/opendaylight/md-sal/sal-inmemory-datastore/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/SnapshotBackedReadTransaction.java
+++ b/opendaylight/md-sal/sal-inmemory-datastore/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/SnapshotBackedReadTransaction.java
@@ -7,19 +7,19 @@
  */
 package org.opendaylight.controller.md.sal.dom.store.impl;
 
-import static com.google.common.base.Preconditions.checkNotNull;
-import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
 import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
 import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadTransaction;
 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.google.common.base.Optional;
-import com.google.common.base.Preconditions;
-import com.google.common.util.concurrent.CheckedFuture;
-import com.google.common.util.concurrent.Futures;
+import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
  *
@@ -33,7 +33,7 @@ final class SnapshotBackedReadTransaction extends AbstractDOMStoreTransaction
                                           implements DOMStoreReadTransaction {
 
     private static final Logger LOG = LoggerFactory.getLogger(SnapshotBackedReadTransaction.class);
-    private DataTreeSnapshot stableSnapshot;
+    private volatile DataTreeSnapshot stableSnapshot;
 
     public SnapshotBackedReadTransaction(final Object identifier, final DataTreeSnapshot snapshot) {
         super(identifier);
@@ -52,15 +52,29 @@ final class SnapshotBackedReadTransaction extends AbstractDOMStoreTransaction
         LOG.debug("Tx: {} Read: {}", getIdentifier(), path);
         checkNotNull(path, "Path must not be null.");
 
-        if(stableSnapshot == null) {
+        final DataTreeSnapshot snapshot = stableSnapshot;
+        if (snapshot == null) {
             return Futures.immediateFailedCheckedFuture(new ReadFailedException("Transaction is closed"));
         }
 
         try {
-            return Futures.immediateCheckedFuture(stableSnapshot.readNode(path));
+            return Futures.immediateCheckedFuture(snapshot.readNode(path));
         } catch (Exception e) {
             LOG.error("Tx: {} Failed Read of {}", getIdentifier(), path, e);
             return Futures.immediateFailedCheckedFuture(new ReadFailedException("Read failed",e));
         }
     }
-}
\ No newline at end of file
+
+    @Override
+    public CheckedFuture<Boolean, ReadFailedException> exists(YangInstanceIdentifier path) {
+        LOG.debug("Tx: {} Exists: {}", getIdentifier(), path);
+        checkNotNull(path, "Path must not be null.");
+
+        try {
+            return Futures.immediateCheckedFuture(
+                read(path).checkedGet().isPresent());
+        } catch (ReadFailedException e) {
+            return Futures.immediateFailedCheckedFuture(e);
+        }
+    }
+}