Github user jdasch commented on a diff in the pull request:
https://github.com/apache/incubator-rya/pull/237#discussion_r143750533
--- Diff:
common/rya.api/src/main/java/org/apache/rya/api/functions/DateTimeWithinPeriod.java
---
@@ -0,0 +1,130 @@
+/*
+ * 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.api.functions;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.time.Duration;
+import java.time.Instant;
+
+import org.openrdf.model.Literal;
+import org.openrdf.model.URI;
+import org.openrdf.model.Value;
+import org.openrdf.model.ValueFactory;
+import org.openrdf.model.datatypes.XMLDatatypeUtil;
+import org.openrdf.model.vocabulary.FN;
+import org.openrdf.model.vocabulary.XMLSchema;
+import org.openrdf.query.algebra.evaluation.ValueExprEvaluationException;
+import org.openrdf.query.algebra.evaluation.function.Function;
+
+/**
+ * This {@link Function} determines whether two {@link
XMLSchema#DATETIME}s occur within a specified period of time of
+ * one another. The method {@link Function#evaluate(ValueFactory,
Value...)} expects four values, where the first two
+ * values are the datetimes, the third value is an integer indicating the
period, and the fourth value is a URI
+ * indicating the time unit of the period. The URI must be of Type
DurationDescription in the OWL-Time ontology (see
+ * <a href
="https://www.w3.org/TR/owl-time/";>https://www.w3.org/TR/owl-time/</a>).
Examples of valid time unit URIs can
+ * be found in the class {@link OWLTime} and below
+ * <ul>
--- End diff --
Nit: As a user, I'd love a 5th optional argument that allows me to specify
exclusiveness or inclusiveness of the period.
---
