Github user kchilton2 commented on a diff in the pull request:
https://github.com/apache/incubator-rya/pull/251#discussion_r153282346
--- Diff:
extras/rya.pcj.fluo/pcj.fluo.app/src/main/java/org/apache/rya/indexing/pcj/fluo/app/util/BindingHashShardingFunction.java
---
@@ -0,0 +1,159 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.apache.rya.indexing.pcj.fluo.app.util;
+
+import static
org.apache.rya.indexing.pcj.fluo.app.IncrementalUpdateConstants.NODEID_BS_DELIM;
+import static
org.apache.rya.indexing.pcj.storage.accumulo.BindingSetStringConverter.TYPE_DELIM;
+
+import org.apache.fluo.api.data.Bytes;
+import org.apache.fluo.api.data.Bytes.BytesBuilder;
+import org.apache.rya.api.domain.RyaType;
+import org.apache.rya.api.resolver.RdfToRyaConversions;
+import
org.apache.rya.indexing.pcj.storage.accumulo.BindingSetStringConverter;
+import org.apache.rya.indexing.pcj.storage.accumulo.VariableOrder;
+import org.apache.rya.indexing.pcj.storage.accumulo.VisibilityBindingSet;
+import org.openrdf.model.Value;
+
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import com.google.common.hash.Hashing;
+
+/**
+ * This class adds and removes a hash to and from the rowId for sharding
purposes.
+ *
+ */
+public class BindingHashShardingFunction {
+
+ private static final BindingSetStringConverter BS_CONVERTER = new
BindingSetStringConverter();
+ private static final int HASH_LEN = 4;
+
+ /**
+ * Generates a sharded rowId.
+ *
+ * @param nodeId - Node Id with type and UUID
+ * @param varOrder - VarOrder used to order BindingSet values
+ * @param bs - BindingSet with partially formed query values
+ * @return - serialized Bytes rowId for storing BindingSet results in
Fluo
+ */
+ public static Bytes addShard(String nodeId, VariableOrder varOrder,
VisibilityBindingSet bs) {
+ String[] rowPrefixAndId = nodeId.split("_");
+ Preconditions.checkArgument(rowPrefixAndId.length == 2);
+ String prefix = rowPrefixAndId[0];
+ String id = rowPrefixAndId[1];
+
+ String firstBindingString = "";
+ Bytes rowSuffix = Bytes.of(id);
+ if (varOrder.getVariableOrders().size() > 0) {
+ VariableOrder first = new
VariableOrder(varOrder.getVariableOrders().get(0));
+ firstBindingString = BS_CONVERTER.convert(bs, first);
+ rowSuffix = RowKeyUtil.makeRowKey(id, varOrder, bs);
+ }
+
+ BytesBuilder builder = Bytes.builder();
+ builder.append(Bytes.of(prefix + ":"));
+ builder.append(genHash(Bytes.of(id + NODEID_BS_DELIM +
firstBindingString)));
+ builder.append(":");
+ builder.append(rowSuffix);
+ return builder.toBytes();
+ }
+
+ /**
+ * Generates a sharded rowId.
+ *
+ * @param nodeId - Node Id with type and UUID
+ * @param firstBsVal - String representation of the first BsValue
+ * @return - serialized Bytes prefix for scanning rows
+ */
+ public static Bytes getShardedScanPrefix(String nodeId, Value
firstBsVal) {
--- End diff --
null check nodeId
---
