Introduce ShardStrategy and related code

Change-Id: I0df1f18f7b3488acae440e3375e155ae7ee06abf
Signed-off-by: Moiz Raja <moraja@cisco.com>

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/DefaultShardStrategy.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/DefaultShardStrategy.java
new file mode 100644 (file)
index 0000000..a8ab5c4
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/DefaultShardStrategy.java
@@ -0,0 +1,28 @@
+/*
+ * 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.cluster.datastore.shardstrategy;
+
+import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
+
+/**
+ * The DefaultShardStrategy basically puts all data into the default Shard
+ * <p>
+ *   The default shard stores data for all modules for which a specific set of shards has not been configured
+ * </p>
+ */
+public class DefaultShardStrategy implements ShardStrategy{
+
+  public static final String NAME = "default";
+  public static final String DEFAULT_SHARD = "default";
+
+  @Override
+  public String findShard(InstanceIdentifier path) {
+    return DEFAULT_SHARD;
+  }
+}

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategy.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategy.java
new file mode 100644 (file)
index 0000000..f75eb2d
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategy.java
@@ -0,0 +1,24 @@
+/*
+ * 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.cluster.datastore.shardstrategy;
+
+import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
+
+/**
+ * The role of ShardStrategy is to figure out which Shards a given piece of data belongs to
+ */
+public interface ShardStrategy {
+  /**
+   * Find the name of the shard in which the data pointed to by the specified path belongs in
+   *
+   * @param path The location of the data in the logical tree
+   * @return
+   */
+  String findShard(InstanceIdentifier path);
+}

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategyFactory.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategyFactory.java
new file mode 100644 (file)
index 0000000..2105379
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategyFactory.java
@@ -0,0 +1,48 @@
+/*
+ * 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.cluster.datastore.shardstrategy;
+
+import com.google.common.base.Preconditions;
+import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class ShardStrategyFactory {
+  private static final Map<String, ShardStrategy> moduleNameToStrategyMap = new ConcurrentHashMap();
+
+  private static final String UNKNOWN_MODULE_NAME = "unknown";
+
+  public static ShardStrategy getStrategy(InstanceIdentifier path){
+    Preconditions.checkNotNull(path, "path should not be null");
+
+    String moduleName = getModuleName(path);
+    ShardStrategy shardStrategy = moduleNameToStrategyMap.get(moduleName);
+    if(shardStrategy == null){
+      return new DefaultShardStrategy();
+    }
+
+    return shardStrategy;
+  }
+
+
+  private static String getModuleName(InstanceIdentifier path){
+    return UNKNOWN_MODULE_NAME;
+  }
+
+  /**
+   * This is to be used in the future to register a custom shard strategy
+   *
+   * @param moduleName
+   * @param shardStrategy
+   */
+  public static void registerShardStrategy(String moduleName, ShardStrategy shardStrategy){
+    throw new UnsupportedOperationException("registering a custom shard strategy not supported yet");
+  }
+}

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/shardstrategy/DefaultShardStrategyTest.java b/opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/shardstrategy/DefaultShardStrategyTest.java
new file mode 100644 (file)
index 0000000..d3ba9b1
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/shardstrategy/DefaultShardStrategyTest.java
@@ -0,0 +1,14 @@
+package org.opendaylight.controller.cluster.datastore.shardstrategy;
+
+import junit.framework.Assert;
+import org.junit.Test;
+import org.opendaylight.controller.md.cluster.datastore.model.TestModel;
+
+public class DefaultShardStrategyTest {
+
+  @Test
+  public void testFindShard() throws Exception {
+    String shard = new DefaultShardStrategy().findShard(TestModel.TEST_PATH);
+    Assert.assertEquals(DefaultShardStrategy.DEFAULT_SHARD, shard);
+  }
+}
\ No newline at end of file

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategyFactoryTest.java b/opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategyFactoryTest.java
new file mode 100644 (file)
index 0000000..2cff981
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/shardstrategy/ShardStrategyFactoryTest.java
@@ -0,0 +1,29 @@
+package org.opendaylight.controller.cluster.datastore.shardstrategy;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.opendaylight.controller.md.cluster.datastore.model.TestModel;
+
+import static junit.framework.Assert.assertNotNull;
+
+public class ShardStrategyFactoryTest {
+
+  @Rule
+  public ExpectedException expectedEx = ExpectedException.none();
+
+  @Test
+  public void testGetStrategy(){
+    ShardStrategy strategy = ShardStrategyFactory.getStrategy(TestModel.TEST_PATH);
+    assertNotNull(strategy);
+  }
+
+  @Test
+  public void testGetStrategyNullPointerExceptionWhenPathIsNull(){
+    expectedEx.expect(NullPointerException.class);
+    expectedEx.expectMessage("path should not be null");
+
+    ShardStrategyFactory.getStrategy(null);
+  }
+
+}
\ No newline at end of file