Bug 1073: Implemented Transaction chain on InMemoryDOMDataStore level.

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

diff --git a/opendaylight/md-sal/sal-dom-broker/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/SnapshotBackedReadTransaction.java b/opendaylight/md-sal/sal-dom-broker/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/SnapshotBackedReadTransaction.java
new file mode 100644 (file)
index 0000000..315293f
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+++ b/opendaylight/md-sal/sal-dom-broker/src/main/java/org/opendaylight/controller/md/sal/dom/store/impl/SnapshotBackedReadTransaction.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.md.sal.dom.store.impl;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
+
+import org.opendaylight.controller.md.sal.dom.store.impl.tree.DataTreeSnapshot;
+import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadTransaction;
+import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+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.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+
+/**
+ *
+ * Implementation of read-only transaction backed by {@link DataTreeSnapshot}
+ *
+ * Implementation of read-only transaction backed by {@link DataTreeSnapshot}
+ * which delegates most of its calls to similar methods provided by underlying snapshot.
+ *
+ */
+final class SnapshotBackedReadTransaction extends AbstractDOMStoreTransaction implements
+DOMStoreReadTransaction {
+    private static final Logger LOG = LoggerFactory.getLogger(SnapshotBackedReadTransaction.class);
+    private DataTreeSnapshot stableSnapshot;
+
+    public SnapshotBackedReadTransaction(final Object identifier, final DataTreeSnapshot snapshot) {
+        super(identifier);
+        this.stableSnapshot = Preconditions.checkNotNull(snapshot);
+        LOG.debug("ReadOnly Tx: {} allocated with snapshot {}", identifier, snapshot);
+    }
+
+    @Override
+    public void close() {
+        LOG.debug("Store transaction: {} : Closed", getIdentifier());
+        stableSnapshot = null;
+    }
+
+    @Override
+    public ListenableFuture<Optional<NormalizedNode<?, ?>>> read(final InstanceIdentifier path) {
+        checkNotNull(path, "Path must not be null.");
+        checkState(stableSnapshot != null, "Transaction is closed");
+        return Futures.immediateFuture(stableSnapshot.readNode(path));
+    }
+}
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