Added BMv2 demo apps (onos1.6 cherry-pick)

Change-Id: I19484a826acce724c1fcd5b6e9910d724bda686f
diff --git a/apps/bmv2-demo/ecmp/src/main/java/org/onosproject/bmv2/demo/app/ecmp/EcmpGroupTableSelectorBuilder.java b/apps/bmv2-demo/ecmp/src/main/java/org/onosproject/bmv2/demo/app/ecmp/EcmpGroupTableSelectorBuilder.java
new file mode 100644
index 0000000..e9ce0cf
--- /dev/null
+++ b/apps/bmv2-demo/ecmp/src/main/java/org/onosproject/bmv2/demo/app/ecmp/EcmpGroupTableSelectorBuilder.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.bmv2.demo.app.ecmp;
+
+import com.google.common.collect.ImmutableMap;
+import org.onlab.util.ImmutableByteSequence;
+import org.onosproject.bmv2.api.context.Bmv2HeaderTypeModel;
+import org.onosproject.bmv2.api.runtime.Bmv2ExactMatchParam;
+import org.onosproject.bmv2.api.runtime.Bmv2ExtensionSelector;
+import org.onosproject.bmv2.api.utils.Bmv2TranslatorUtils;
+import org.onosproject.net.flow.criteria.ExtensionSelector;
+
+import static org.onosproject.bmv2.api.utils.Bmv2TranslatorUtils.fitByteSequence;
+import static org.onosproject.bmv2.demo.app.ecmp.EcmpFabricApp.ECMP_CONTEXT;
+import static org.onosproject.bmv2.demo.app.ecmp.EcmpInterpreter.*;
+
+/**
+ * Builder of ECMP group table extension selector.
+ */
+public class EcmpGroupTableSelectorBuilder {
+
+    private int groupId;
+    private int selector;
+
+    /**
+     * Sets the ECMP group ID.
+     *
+     * @param groupId an integer value
+     * @return this
+     */
+    public EcmpGroupTableSelectorBuilder withGroupId(int groupId) {
+        this.groupId = groupId;
+        return this;
+    }
+
+    /**
+     * Sets the ECMP selector.
+     *
+     * @param selector an integer value
+     * @return this
+     */
+    public EcmpGroupTableSelectorBuilder withSelector(int selector) {
+        this.selector = selector;
+        return this;
+    }
+
+    /**
+     * Returns a new extension selector.
+     *
+     * @return an extension selector
+     */
+    public ExtensionSelector build() {
+        Bmv2HeaderTypeModel headerTypeModel = ECMP_CONTEXT.configuration().headerType(ECMP_METADATA_T);
+        int groupIdBitWidth = headerTypeModel.field(GROUP_ID).bitWidth();
+        int selectorBitWidth = headerTypeModel.field(SELECTOR).bitWidth();
+
+        try {
+            ImmutableByteSequence groupIdBs = fitByteSequence(ImmutableByteSequence.copyFrom(groupId),
+                                                              groupIdBitWidth);
+            ImmutableByteSequence selectorBs = fitByteSequence(ImmutableByteSequence.copyFrom(selector),
+                                                               selectorBitWidth);
+
+            Bmv2ExactMatchParam groupIdMatch = new Bmv2ExactMatchParam(groupIdBs);
+            Bmv2ExactMatchParam hashMatch = new Bmv2ExactMatchParam(selectorBs);
+
+            return new Bmv2ExtensionSelector(ImmutableMap.of(
+                    ECMP_METADATA + "." + GROUP_ID, groupIdMatch,
+                    ECMP_METADATA + "." + SELECTOR, hashMatch));
+
+        } catch (Bmv2TranslatorUtils.ByteSequenceFitException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}