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https://issues.apache.org/jira/browse/NIFI-1571?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15194572#comment-15194572
]
ASF GitHub Bot commented on NIFI-1571:
--------------------------------------
Github user olegz commented on a diff in the pull request:
https://github.com/apache/nifi/pull/271#discussion_r56106464
--- Diff:
nifi-nar-bundles/nifi-spring-bundle/nifi-spring-processors/src/main/java/org/apache/nifi/spring/SpringContextFactory.java
---
@@ -0,0 +1,139 @@
+/*
+ * 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.spring;
+
+import java.io.File;
+import java.io.InputStream;
+import java.lang.reflect.Constructor;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.apache.commons.io.IOUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Helper class which provides factory method to create and initialize
Spring
+ * Application Context while scoping it within the dedicated Class Loader.
+ */
+final class SpringContextFactory {
+
+ private static final Logger logger =
LoggerFactory.getLogger(SpringContextFactory.class);
+
+ private static final String SC_DELEGATE_NAME =
"org.apache.nifi.spring.bootstrap.SpringContextDelegate";
+
+ /**
+ * Creates and instance of Spring Application Context scoped within a
+ * dedicated Class Loader
+ */
+ static SpringDataExchanger createSpringContextDelegate(String
classpath, String config) {
+ System.out.println(SpringContextFactory.class.getClassLoader());
+ URL[] urls = gatherAdditionalClassPathUrls(classpath);
+ SpringContextClassLoader contextCl = new
SpringContextClassLoader(urls,
+ SpringContextFactory.class.getClassLoader());
+ try {
+ InputStream delegateStream =
contextCl.getResourceAsStream(SC_DELEGATE_NAME.replace('.', '/') + ".class");
+ byte[] delegateBytes = IOUtils.toByteArray(delegateStream);
+ Class<?> clazz = contextCl.doDefineClass(SC_DELEGATE_NAME,
delegateBytes, 0, delegateBytes.length);
+ Constructor<?> ctr =
clazz.getDeclaredConstructor(String.class);
+ ctr.setAccessible(true);
+ SpringDataExchanger springDelegate = (SpringDataExchanger)
ctr.newInstance(config);
+ if (logger.isInfoEnabled()) {
+ logger.info("Successfully instantiated Spring Application
Context from '" + config + "'");
+ }
+ return springDelegate;
+ } catch (Exception e) {
+ try {
+ contextCl.close();
+ } catch (Exception e2) {
+ // ignore
+ }
+ throw new IllegalStateException("Failed to instantiate Spring
Application Context. Config path: '" + config
+ + "'; Classpath: " + Arrays.asList(urls), e);
+ }
+ }
+
+ /**
+ *
+ */
+ private static URL[] gatherAdditionalClassPathUrls(String path) {
+ if (logger.isDebugEnabled()) {
+ logger.debug("Adding additional resources from '" + path + "'
to the classpath.");
+ }
+ File libraryDir = new File(path);
+ if (libraryDir.exists() && libraryDir.isDirectory()) {
+ String[] cpResourceNames = libraryDir.list();
+ try {
+ URLClassLoader thisCl = (URLClassLoader)
SpringContextFactory.class.getClassLoader();
+ List<URL> urls = new ArrayList<>();
+ for (int i = 0; i < cpResourceNames.length; i++) {
+ if (!isDuplicate(thisCl.getURLs(),
cpResourceNames[i])) {
+ URL url = new File(libraryDir,
cpResourceNames[i]).toURI().toURL();
+ urls.add(url);
+ if (logger.isDebugEnabled()) {
+ logger.debug("Identifying additional resource
to the classpath: " + url);
+ }
+ }
+ }
+ return urls.toArray(new URL[] {});
+ } catch (Exception e) {
+ throw new IllegalStateException(
+ "Failed to parse user libraries from '" +
libraryDir.getAbsolutePath() + "'", e);
+ }
+ } else {
+ throw new IllegalArgumentException("Path '" +
libraryDir.getAbsolutePath()
+ + "' is not valid because it doesn't exist or does not
point to a directory.");
+ }
+ }
+
+ /**
+ *
+ */
+ static boolean isDuplicate(URL[] currentURLs, String resourceName) {
+ if (resourceName.startsWith("spring")) {
+ resourceName = resourceName.substring(0,
resourceName.lastIndexOf("-"));
--- End diff --
Let me review this. This whole method will probably go since this NAR no
longer packages any Spring JARs. Basically it's now one of the thinnest NARs in
NiFi and only comes with 4-5 JARs
> Provide generic processor that would bootstrap itself from Spring's
> Application Context
> ---------------------------------------------------------------------------------------
>
> Key: NIFI-1571
> URL: https://issues.apache.org/jira/browse/NIFI-1571
> Project: Apache NiFi
> Issue Type: New Feature
> Reporter: Oleg Zhurakousky
> Assignee: Oleg Zhurakousky
> Fix For: 0.6.0
>
>
> So, several clients have expressed interests in using WorkFlow orchestration
> frameworks such as Camel, Spring Integration etc. to be able to encapsulate
> yet modularize and externalize the complexity of some of the custom
> processors as well as handle some of the use cases that fall outside of scope
> of Data Flow paradigm (e.g., transactional context and XA between two+
> Processors).
> There is already a ticket to provide Camel support - NIFI-924. However
> realizing that both Camel and naturally Spring Integration is based on Spring
> Application Context it appears that instead of having multiple extensions we
> should have a more generic extension for a Processor that would delegate its
> processing to a bean in provided Spring Application Context (AC). This way AC
> becomes a black box and could contain anything (e.g., Camel, Spring
> Integration or some custom user code).
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