Github user meiercaleb commented on a diff in the pull request:
https://github.com/apache/incubator-rya/pull/251#discussion_r153624484
--- Diff:
extras/rya.pcj.fluo/pcj.fluo.app/src/main/java/org/apache/rya/indexing/pcj/fluo/app/query/StatementPatternIdCache.java
---
@@ -0,0 +1,90 @@
+/*
+ * 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.query;
+
+import static
org.apache.rya.indexing.pcj.fluo.app.IncrementalUpdateConstants.STATEMENT_PATTERN_ID;
+import static
org.apache.rya.indexing.pcj.fluo.app.IncrementalUpdateConstants.VAR_DELIM;
+import static
org.apache.rya.indexing.pcj.fluo.app.query.FluoQueryColumns.STATEMENT_PATTERN_IDS;
+import static
org.apache.rya.indexing.pcj.fluo.app.query.FluoQueryColumns.STATEMENT_PATTERN_IDS_HASH;
+
+import java.util.HashSet;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.locks.ReentrantLock;
+
+import org.apache.fluo.api.client.TransactionBase;
+import org.apache.fluo.api.data.Bytes;
+
+import com.google.common.collect.Sets;
+
+/**
+ * This class caches the StatementPattern Ids so they don't have
+ * to be looked up each time a new Statement needs to be processed
+ * in the TripleObserver.
+ *
+ */
+public class StatementPatternIdCache {
+
+ private final ReentrantLock lock = new ReentrantLock();
+ private static Optional<String> HASH;
+ private static Set<String> IDS;
+
+ public StatementPatternIdCache() {
+ HASH = Optional.empty();
+ IDS = new HashSet<>();
+ }
+
+ /**
+ * This method retrieves the StatementPattern NodeIds registered in
the Fluo table.
+ * This method looks up the hash of the Statement Pattern Id String
hash, and if it
+ * is the same as the cached hash, then the cache Set of nodeIds is
returned. Otherwise,
+ * this method retrieves the ids from the Fluo table. This method is
thread safe.
+ * @param tx
+ * @return - Set of StatementPattern nodeIds
+ */
+ public Set<String> getStatementPatternIds(TransactionBase tx) {
--- End diff --
Done.
---
