Github user ijokarumawak commented on a diff in the pull request:
https://github.com/apache/nifi/pull/2335#discussion_r157231905
--- Diff:
nifi-nar-bundles/nifi-atlas-bundle/nifi-atlas-reporting-task/src/main/java/org/apache/nifi/atlas/provenance/NiFiProvenanceEventAnalyzerFactory.java
---
@@ -0,0 +1,105 @@
+/*
+ * 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.nifi.atlas.provenance;
+
+import org.apache.nifi.provenance.ProvenanceEventType;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Map;
+import java.util.ServiceLoader;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.regex.Pattern;
+
+public class NiFiProvenanceEventAnalyzerFactory {
+
+ private static final Logger logger =
LoggerFactory.getLogger(NiFiProvenanceEventAnalyzerFactory.class);
+ private static final Map<Pattern, NiFiProvenanceEventAnalyzer>
analyzersForComponentType = new ConcurrentHashMap<>();
+ private static final Map<Pattern, NiFiProvenanceEventAnalyzer>
analyzersForTransitUri = new ConcurrentHashMap<>();
+ private static final Map<ProvenanceEventType,
NiFiProvenanceEventAnalyzer> analyzersForProvenanceEventType = new
ConcurrentHashMap<>();
+ private static boolean loaded = false;
+
+ private static void loadAnalyzers() {
+ logger.debug("Loading NiFiProvenanceEventAnalyzer ...");
+ final ServiceLoader<NiFiProvenanceEventAnalyzer> serviceLoader
+ = ServiceLoader.load(NiFiProvenanceEventAnalyzer.class);
+ serviceLoader.forEach(analyzer -> {
+ addAnalyzer(analyzer.targetComponentTypePattern(),
analyzersForComponentType, analyzer);
+ addAnalyzer(analyzer.targetTransitUriPattern(),
analyzersForTransitUri, analyzer);
+ final ProvenanceEventType eventType =
analyzer.targetProvenanceEventType();
+ if (eventType != null) {
+ if
(analyzersForProvenanceEventType.containsKey(eventType)) {
+ logger.warn("Fo ProvenanceEventType {}, an Analyzer {}
is already assigned." +
+ " Only one analyzer for a type can be
registered. Ignoring {}",
+ eventType,
analyzersForProvenanceEventType.get(eventType), analyzer);
+ }
+ analyzersForProvenanceEventType.put(eventType, analyzer);
+ }
+ });
+ logger.info("Loaded NiFiProvenanceEventAnalyzers:
componentTypes={}, transitUris={}", analyzersForComponentType,
analyzersForTransitUri);
+ }
+
+ private static void addAnalyzer(String patternStr, Map<Pattern,
NiFiProvenanceEventAnalyzer> toAdd,
+ NiFiProvenanceEventAnalyzer analyzer) {
+ if (patternStr != null && !patternStr.isEmpty()) {
+ Pattern pattern = Pattern.compile(patternStr.trim());
+ toAdd.put(pattern, analyzer);
+ }
+ }
+
+ /**
+ * Find and retrieve NiFiProvenanceEventAnalyzer implementation for
the specified targets.
+ * Pattern matching is performed by following order, and the one found
at first is returned:
+ * <ol>
+ * <li>Component type name. Use an analyzer supporting the Component
type with its {@link NiFiProvenanceEventAnalyzer#targetProvenanceEventType()}.
+ * <li>TransitUri. Use an analyzer supporting the TransitUri with its
{@link NiFiProvenanceEventAnalyzer#targetTransitUriPattern()}.
+ * <li>Provenance Event Type. Use an analyzer supporting the
Provenance Event Type with its {@link
NiFiProvenanceEventAnalyzer#targetProvenanceEventType()}.
+ * </ol>
+ * @param typeName NiFi component type name.
+ * @param transitUri Transit URI.
+ * @param eventType Provenance event type.
+ * @return Instance of NiFiProvenanceEventAnalyzer if one is found for
the specified className, otherwise null.
+ */
+ public static NiFiProvenanceEventAnalyzer getAnalyzer(String typeName,
String transitUri, ProvenanceEventType eventType) {
+
+ if (!loaded) {
--- End diff --
Thank you! I was referring an ancient blog post to implement this logic.. I
will update it to use static lazy initializer.
---
