Introduce EntityOwnerSelectionStrategy

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

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/selectionstrategy/FirstCandidateSelectionStrategy.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/selectionstrategy/FirstCandidateSelectionStrategy.java
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+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/selectionstrategy/FirstCandidateSelectionStrategy.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2015 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.cluster.datastore.entityownership.selectionstrategy;
+
+import com.google.common.base.Preconditions;
+import java.util.Collection;
+
+/**
+ * The FirstCandidateSelectionStrategy always selects the first viable candidate from the list of candidates
+ */
+public class FirstCandidateSelectionStrategy implements EntityOwnerSelectionStrategy {
+
+    public static final FirstCandidateSelectionStrategy INSTANCE = new FirstCandidateSelectionStrategy();
+
+    @Override
+    public long selectionDelayInMillis() {
+        return 0;
+    }
+
+    @Override
+    public String newOwner(Collection<String> viableCandidates) {
+        Preconditions.checkArgument(viableCandidates.size() > 0, "No viable candidates provided");
+        return viableCandidates.iterator().next();
+    }
+}