BUG-5280: synchronize access to local histories

[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / DatastoreSnapshotRestore.java

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DatastoreSnapshotRestore.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DatastoreSnapshotRestore.java
index bed23895d3e5dbdd9681631c494855130f0d5a9a..e736ddae3136ae43a8b7163e4a4941990e8184dd 100644 (file)
--- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DatastoreSnapshotRestore.java
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DatastoreSnapshotRestore.java
@@ -15,7 +15,6 @@ import java.io.InputStream;
 import java.io.ObjectInputStream;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot;
 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshotList;
@@ -35,41 +34,33 @@ public class DatastoreSnapshotRestore {
 
     private final String restoreDirectoryPath;
     private final Map<String, DatastoreSnapshot> datastoreSnapshots = new ConcurrentHashMap<>();
-    private final AtomicBoolean initialized = new AtomicBoolean();
 
-    public static void createInstance(String restoreDirectoryPath) {
+    public static DatastoreSnapshotRestore instance(String restoreDirectoryPath) {
         instance.compareAndSet(null, new DatastoreSnapshotRestore(restoreDirectoryPath));
-    }
-
-    public static void removeInstance() {
-        instance.set(null);
-    }
-
-    public static DatastoreSnapshotRestore instance() {
-        DatastoreSnapshotRestore localInstance = instance.get();
-        return Preconditions.checkNotNull(localInstance, "DatastoreSnapshotRestore instance was not created");
+        return instance.get();
     }
 
     private DatastoreSnapshotRestore(String restoreDirectoryPath) {
         this.restoreDirectoryPath = Preconditions.checkNotNull(restoreDirectoryPath);
     }
 
-    private void initialize() {
-        if(!initialized.compareAndSet(false, true)) {
-            return;
-        }
+    // synchronize this method so that, in case of concurrent access to getAndRemove(),
+    // no one ends up with partially initialized data
+    @SuppressWarnings("checkstyle:IllegalCatch")
+    private synchronized void initialize() {
 
         File restoreDirectoryFile = new File(restoreDirectoryPath);
 
         String[] files = restoreDirectoryFile.list();
-        if(files == null || files.length == 0) {
+        if (files == null || files.length == 0) {
             LOG.debug("Restore directory {} does not exist or is empty", restoreDirectoryFile);
             return;
         }
 
-        if(files.length > 1) {
-            LOG.error("Found {} files in clustered datastore restore directory {} - expected 1. No restore will be attempted",
-                    files.length, restoreDirectoryFile);
+        if (files.length > 1) {
+            LOG.error(
+                "Found {} files in clustered datastore restore directory {} - expected 1. No restore will be attempted",
+                files.length, restoreDirectoryFile);
             return;
         }
 
@@ -77,24 +68,25 @@ public class DatastoreSnapshotRestore {
 
         LOG.info("Clustered datastore will be restored from file {}", restoreFile);
 
-        try(FileInputStream fis = new FileInputStream(restoreFile)) {
+        try (FileInputStream fis = new FileInputStream(restoreFile)) {
             DatastoreSnapshotList snapshots = deserialize(fis);
             LOG.debug("Deserialized {} snapshots", snapshots.size());
 
-            for(DatastoreSnapshot snapshot: snapshots) {
+            for (DatastoreSnapshot snapshot: snapshots) {
                 datastoreSnapshots.put(snapshot.getType(), snapshot);
             }
-        } catch (Exception e) {
+        } catch (ClassNotFoundException | IOException e) {
             LOG.error("Error reading clustered datastore restore file {}", restoreFile, e);
         } finally {
-            if(!restoreFile.delete()) {
+            if (!restoreFile.delete()) {
                 LOG.error("Could not delete clustered datastore restore file {}", restoreFile);
             }
         }
     }
 
-    private DatastoreSnapshotList deserialize(InputStream inputStream) throws IOException, ClassNotFoundException {
-        try(ObjectInputStream ois = new ObjectInputStream(inputStream)) {
+    private static DatastoreSnapshotList deserialize(InputStream inputStream)
+            throws IOException, ClassNotFoundException {
+        try (ObjectInputStream ois = new ObjectInputStream(inputStream)) {
             return (DatastoreSnapshotList) ois.readObject();
         }
     }