Github user meiercaleb commented on a diff in the pull request:
https://github.com/apache/incubator-rya/pull/177#discussion_r128001523
--- Diff:
extras/rya.periodic.service/periodic.service.notification/src/main/java/org/apache/rya/periodic/notification/application/PeriodicNotificationApplication.java
---
@@ -0,0 +1,212 @@
+/*
+ * 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.periodic.notification.application;
+
+import org.apache.log4j.Logger;
+import org.apache.rya.indexing.pcj.fluo.app.util.PeriodicQueryUtil;
+import org.apache.rya.periodic.notification.api.BinPruner;
+import org.apache.rya.periodic.notification.api.LifeCycle;
+import org.apache.rya.periodic.notification.api.NodeBin;
+import
org.apache.rya.periodic.notification.api.NotificationCoordinatorExecutor;
+import org.apache.rya.periodic.notification.exporter.BindingSetRecord;
+import org.apache.rya.periodic.notification.exporter.KafkaExporterExecutor;
+import
org.apache.rya.periodic.notification.processor.NotificationProcessorExecutor;
+import
org.apache.rya.periodic.notification.pruner.PeriodicQueryPrunerExecutor;
+import
org.apache.rya.periodic.notification.registration.kafka.KafkaNotificationProvider;
+import org.openrdf.query.algebra.evaluation.function.Function;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * The PeriodicNotificationApplication runs the key components of the
Periodic
+ * Query Service. It consists of a {@link KafkaNotificationProvider}, a
+ * {@link NotificationCoordinatorExecutor}, a
+ * {@link NotificationProcessorExecutor}, a {@link KafkaExporterExecutor},
and a
+ * {@link PeriodicQueryPrunerExecutor}. These services run in coordination
with
+ * one another to perform the following tasks in the indicated order: <br>
+ * <li>Retrieve new requests to generate periodic notifications from Kafka
+ * <li>Register them with the {@link NotificationCoordinatorExecutor} to
+ * generate the periodic notifications
+ * <li>As notifications are generated, they are added to a work queue that
is
+ * monitored by the {@link NotificationProcessorExecutor}.
+ * <li>The processor processes the notifications by reading all of the
query
+ * results corresponding to the bin and query id indicated by the
notification.
+ * <li>After reading the results, the processor adds a {@link
BindingSetRecord}
+ * to a work queue monitored by the {@link KafkaExporterExecutor}.
+ * <li>The processor then adds a {@link NodeBin} to a workqueue monitored
by the
+ * {@link BinPruner}
+ * <li>The exporter processes the BindingSetRecord by exporing the result
to
+ * Kafka
+ * <li>The BinPruner processes the NodeBin by cleaning up the results for
the
+ * indicated bin and query in Accumulo and Fluo. <br>
+ * <br>
+ * The purpose of this Periodic Query Service is to facilitate the ability
to
+ * answer Periodic Queries using the Rya Fluo application, where a Periodic
+ * Query is any query requesting periodic updates about events that
occurred
+ * within a given window of time of this instant. This is also known as a
+ * rolling window query. Period Queries can be expressed using SPARQL by
+ * including the {@link Function} indicated by the URI
+ * {@link PeriodicQueryUtil#PeriodicQueryURI}. The user must provide this
+ * Function with the following arguments: the temporal variable in the
query
+ * that will be filtered on, the window of time that events must occur
within,
+ * the period at which the user wants to receive updates, and the time
unit. The
+ * following query requests all observations that occurred within the last
+ * minute and requests updates every 15 seconds. It also performs a count
on
+ * those observations. <br>
+ * <br>
+ * <li>prefix function: http://org.apache.rya/function#
+ * <li>"prefix time: http://www.w3.org/2006/time#
+ * <li>"select (count(?obs) as ?total) where {
+ * <li>"Filter(function:periodic(?time, 1, .25, time:minutes))
+ * <li>"?obs uri:hasTime ?time.
+ * <li>"?obs uri:hasId ?id }
+ * <li>
+ */
+public class PeriodicNotificationApplication implements LifeCycle {
+
+ private static final Logger log =
Logger.getLogger(PeriodicNotificationApplication.class);
+ private NotificationCoordinatorExecutor coordinator;
+ private KafkaNotificationProvider provider;
+ private PeriodicQueryPrunerExecutor pruner;
+ private NotificationProcessorExecutor processor;
+ private KafkaExporterExecutor exporter;
+ private boolean running = false;
+
+ /**
+ * Creates a PeriodicNotificationApplication
+ * @param provider - {@link KafkaNotificationProvider} that retrieves
new Notificaiton requests from Kafka
+ * @param coordinator - {NotificationCoordinator} that manages
PeriodicNotifications.
+ * @param processor - {@link NotificationProcessorExecutor} that
processes PeriodicNotifications
+ * @param exporter - {@link KafkaExporterExecutor} that exports
periodic results
+ * @param pruner - {@link PeriodicQueryPrunerExecutor} that cleans up
old periodic bins
+ */
+ public PeriodicNotificationApplication(KafkaNotificationProvider
provider, NotificationCoordinatorExecutor coordinator,
+ NotificationProcessorExecutor processor, KafkaExporterExecutor
exporter, PeriodicQueryPrunerExecutor pruner) {
+ Preconditions.checkNotNull(provider);
+ Preconditions.checkNotNull(coordinator);
+ Preconditions.checkNotNull(processor);
--- End diff --
done
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