Allow SnapshotBackedReadTransaction customization

In some specific cases we need to customize abort-like handling,
which is already implemented for write-like transactions, but is
not present for read-only transaction.

This patch adds the capability to attach a close() handler and
makes sure AbstractSnapshotBackedTransactionChain takes advantage
of it.

JIRA: CONTROLLER-1879
Change-Id: Ic7027956556b5dd25120ee81613a6151e5dbc501
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>
(cherry picked from commit bd73bf5803137b27e25a647ff056da3f59e0a682)

diff --git a/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/AbstractSnapshotBackedTransactionChain.java b/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/AbstractSnapshotBackedTransactionChain.java
index 4301021eafb21c6290157c2e559b597059dafbab..03003ad2adffc811ad2e66d75f03aeb02bf7ac72 100644 (file)
--- a/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/AbstractSnapshotBackedTransactionChain.java
+++ b/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/AbstractSnapshotBackedTransactionChain.java
@@ -12,6 +12,7 @@ import com.google.common.base.Preconditions;
 import java.util.AbstractMap.SimpleEntry;
 import java.util.Map.Entry;
 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
+import org.opendaylight.mdsal.dom.spi.store.SnapshotBackedReadTransaction.TransactionClosePrototype;
 import org.opendaylight.mdsal.dom.spi.store.SnapshotBackedWriteTransaction.TransactionReadyPrototype;
 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
@@ -26,7 +27,7 @@ import org.slf4j.LoggerFactory;
  */
 @Beta
 public abstract class AbstractSnapshotBackedTransactionChain<T>
-        extends TransactionReadyPrototype<T> implements DOMStoreTransactionChain {
+        extends TransactionReadyPrototype<T> implements DOMStoreTransactionChain, TransactionClosePrototype<T> {
     private abstract static class State {
         /**
          * Allocate a new snapshot.
@@ -131,7 +132,12 @@ public abstract class AbstractSnapshotBackedTransactionChain<T>
     protected DOMStoreReadTransaction newReadOnlyTransaction(T transactionId) {
         final Entry<State, DataTreeSnapshot> entry = getSnapshot();
         return SnapshotBackedTransactions.newReadTransaction(transactionId,
-                getDebugTransactions(), entry.getValue());
+                getDebugTransactions(), entry.getValue(), this);
+    }
+
+    @Override
+    public void transactionClosed(final SnapshotBackedReadTransaction<T> tx) {
+        // Defaults to no-op
     }
 
     @Override
@@ -178,9 +184,8 @@ public abstract class AbstractSnapshotBackedTransactionChain<T>
             if (allocated.getTransaction().equals(tx)) {
                 final boolean success = STATE_UPDATER.compareAndSet(this, localState, idleState);
                 if (!success) {
-                    LOG.warn("Transaction {} aborted, but chain {} s"
-                            + "tate already transitioned from {} to {}, very strange",
-                        tx, this, localState, state);
+                    LOG.warn("Transaction {} aborted, but chain {} state already transitioned from {} to {}, "
+                        + "very strange", tx, this, localState, state);
                 }
             }
         }

diff --git a/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedReadTransaction.java b/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedReadTransaction.java
index ac754f56f277a193f97ceee228c6f5cb593945ae..1c1b34e30dc11e68d8f78cf56218af6b109fe188 100644 (file)
--- a/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedReadTransaction.java
+++ b/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedReadTransaction.java
@@ -13,6 +13,7 @@ import com.google.common.annotations.Beta;
 import com.google.common.util.concurrent.FluentFuture;
 import com.google.common.util.concurrent.MoreExecutors;
 import java.util.Optional;
+import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
 import org.opendaylight.mdsal.common.api.ReadFailedException;
 import org.opendaylight.yangtools.util.concurrent.FluentFutures;
 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
@@ -30,8 +31,15 @@ import org.slf4j.LoggerFactory;
 @Beta
 public final class SnapshotBackedReadTransaction<T> extends
         AbstractDOMStoreTransaction<T> implements DOMStoreReadTransaction, SnapshotBackedTransaction {
-
     private static final Logger LOG = LoggerFactory.getLogger(SnapshotBackedReadTransaction.class);
+
+    @SuppressWarnings("rawtypes")
+    private static final AtomicReferenceFieldUpdater<SnapshotBackedReadTransaction, DataTreeSnapshot> SNAPSHOT_UPDATER =
+            AtomicReferenceFieldUpdater.newUpdater(SnapshotBackedReadTransaction.class, DataTreeSnapshot.class,
+                "stableSnapshot");
+
+    // Guarded by stableSnapshot CAS, hence it does not need to be volatile
+    private TransactionClosePrototype<T> closeImpl;
     private volatile DataTreeSnapshot stableSnapshot;
 
     /**
@@ -41,16 +49,27 @@ public final class SnapshotBackedReadTransaction<T> extends
      * @param debug Enable transaction debugging
      * @param snapshot Snapshot which will be modified.
      */
-    SnapshotBackedReadTransaction(final T identifier, final boolean debug, final DataTreeSnapshot snapshot) {
+    SnapshotBackedReadTransaction(final T identifier, final boolean debug, final DataTreeSnapshot snapshot,
+            final TransactionClosePrototype<T> closeImpl) {
         super(identifier, debug);
         this.stableSnapshot = requireNonNull(snapshot);
+        this.closeImpl = closeImpl;
         LOG.debug("ReadOnly Tx: {} allocated with snapshot {}", identifier, snapshot);
     }
 
     @Override
     public void close() {
+        final DataTreeSnapshot prev = SNAPSHOT_UPDATER.getAndSet(this, null);
+        if (prev == null) {
+            LOG.debug("Store transaction: {} : previously closed", getIdentifier());
+            return;
+        }
+
         LOG.debug("Store transaction: {} : Closed", getIdentifier());
-        stableSnapshot = null;
+        if (closeImpl != null) {
+            closeImpl.transactionClosed(this);
+            closeImpl = null;
+        }
     }
 
     @SuppressWarnings("checkstyle:IllegalCatch")
@@ -84,4 +103,23 @@ public final class SnapshotBackedReadTransaction<T> extends
     public java.util.Optional<DataTreeSnapshot> getSnapshot() {
         return java.util.Optional.ofNullable(stableSnapshot);
     }
+
+    /**
+     * Prototype implementation of {@link SnapshotBackedReadTransaction#close()}.
+     *
+     * <p>
+     * This class is intended to be implemented by Transaction factories responsible for allocation
+     * of {@link org.opendaylight.mdsal.dom.spi.store.SnapshotBackedReadTransaction} and
+     * providing underlying logic for applying implementation.
+     *
+     * @param <T> identifier type
+     */
+    public interface TransactionClosePrototype<T> {
+        /**
+         * Called when a transaction is closed. This is not invoked at most once for every transaction.
+         *
+         * @param tx Transaction which got closed.
+         */
+        void transactionClosed(SnapshotBackedReadTransaction<T> tx);
+    }
 }

diff --git a/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedTransactions.java b/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedTransactions.java
index ccf1f7884da35c59c11bdc1e3d4e6e2bc4eaa0f1..e90c7a474578d049887bb7b1350a5dc61f232eee 100644 (file)
--- a/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedTransactions.java
+++ b/dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedTransactions.java
@@ -7,7 +7,11 @@
  */
 package org.opendaylight.mdsal.dom.spi.store;
 
+import static java.util.Objects.requireNonNull;
+
 import com.google.common.annotations.Beta;
+import org.eclipse.jdt.annotation.NonNull;
+import org.opendaylight.mdsal.dom.spi.store.SnapshotBackedReadTransaction.TransactionClosePrototype;
 import org.opendaylight.mdsal.dom.spi.store.SnapshotBackedWriteTransaction.TransactionReadyPrototype;
 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
 
@@ -22,13 +26,29 @@ public final class SnapshotBackedTransactions {
 
     /**
      * Creates a new read-only transaction.
+     *
      * @param identifier Transaction Identifier
      * @param debug Enable transaction debugging
      * @param snapshot Snapshot which will be modified.
+     * @return A new read-only transaction
      */
-    public static <T> SnapshotBackedReadTransaction<T> newReadTransaction(final T identifier,
+    public static <T> @NonNull SnapshotBackedReadTransaction<T> newReadTransaction(final T identifier,
             final boolean debug, final DataTreeSnapshot snapshot) {
-        return new SnapshotBackedReadTransaction<>(identifier, debug, snapshot);
+        return new SnapshotBackedReadTransaction<>(identifier, debug, snapshot, null);
+    }
+
+    /**
+     * Creates a new read-only transaction.
+     *
+     * @param identifier Transaction Identifier
+     * @param debug Enable transaction debugging
+     * @param snapshot Snapshot which will be modified.
+     * @param closeImpl Implementation of close method
+     * @return A new read-only transaction
+     */
+    public static <T> @NonNull SnapshotBackedReadTransaction<T> newReadTransaction(final T identifier,
+            final boolean debug, final DataTreeSnapshot snapshot, final TransactionClosePrototype<T> closeImpl) {
+        return new SnapshotBackedReadTransaction<>(identifier, debug, snapshot, requireNonNull(closeImpl));
     }
 
     /**
@@ -38,8 +58,9 @@ public final class SnapshotBackedTransactions {
      * @param debug Enable transaction debugging
      * @param snapshot Snapshot which will be modified.
      * @param readyImpl Implementation of ready method.
+     * @return A new read-write transaction
      */
-    public static <T> SnapshotBackedReadWriteTransaction<T> newReadWriteTransaction(final T identifier,
+    public static <T> @NonNull SnapshotBackedReadWriteTransaction<T> newReadWriteTransaction(final T identifier,
             final boolean debug, final DataTreeSnapshot snapshot, final TransactionReadyPrototype<T> readyImpl) {
         return new SnapshotBackedReadWriteTransaction<>(identifier, debug, snapshot, readyImpl);
     }
@@ -51,8 +72,9 @@ public final class SnapshotBackedTransactions {
      * @param debug Enable transaction debugging
      * @param snapshot Snapshot which will be modified.
      * @param readyImpl Implementation of ready method.
+     * @return A new write transaction
      */
-    public static <T> SnapshotBackedWriteTransaction<T> newWriteTransaction(final T identifier,
+    public static <T> @NonNull SnapshotBackedWriteTransaction<T> newWriteTransaction(final T identifier,
             final boolean debug, final DataTreeSnapshot snapshot, final TransactionReadyPrototype<T> readyImpl) {
         return new SnapshotBackedWriteTransaction<>(identifier, debug, snapshot, readyImpl);
     }

diff --git a/dom/mdsal-dom-spi/src/test/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedReadTransactionTest.java b/dom/mdsal-dom-spi/src/test/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedReadTransactionTest.java
index c137b61ae8d4db7b39819ae1a2d3e7dc7818e44a..cf1ccb4aaf6507a350635997cac81808ffa473cf 100644 (file)
--- a/dom/mdsal-dom-spi/src/test/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedReadTransactionTest.java
+++ b/dom/mdsal-dom-spi/src/test/java/org/opendaylight/mdsal/dom/spi/store/SnapshotBackedReadTransactionTest.java
@@ -29,8 +29,9 @@ import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
 public class SnapshotBackedReadTransactionTest {
 
     private static final DataTreeSnapshot DATA_TREE_SNAPSHOT = mock(DataTreeSnapshot.class);
-    private static SnapshotBackedReadTransaction<Object> snapshotBackedReadTransaction =
-            new SnapshotBackedReadTransaction<>(new Object(), false, DATA_TREE_SNAPSHOT);
+
+    private SnapshotBackedReadTransaction<Object> snapshotBackedReadTransaction =
+            new SnapshotBackedReadTransaction<>(new Object(), false, DATA_TREE_SNAPSHOT, null);
 
     @Test
     public void basicTest() throws Exception {
@@ -67,7 +68,8 @@ public class SnapshotBackedReadTransactionTest {
     @Test(expected = ReadFailedException.class)
     public void readNodeTestWithException() throws Throwable {
         doThrow(new NullPointerException("no Node")).when(DATA_TREE_SNAPSHOT).readNode(any());
-        snapshotBackedReadTransaction = new SnapshotBackedReadTransaction<>(new Object(), false, DATA_TREE_SNAPSHOT);
+        snapshotBackedReadTransaction = new SnapshotBackedReadTransaction<>(new Object(), false, DATA_TREE_SNAPSHOT,
+                null);
         try {
             snapshotBackedReadTransaction.read(YangInstanceIdentifier.EMPTY).get();
             fail("Expected ReadFailedException");