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https://issues.apache.org/jira/browse/NIFI-1976?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15336278#comment-15336278
]
ASF GitHub Bot commented on NIFI-1976:
--------------------------------------
Github user JPercivall commented on a diff in the pull request:
https://github.com/apache/nifi/pull/525#discussion_r67525744
--- Diff:
nifi-nar-bundles/nifi-windows-event-log-bundle/nifi-windows-event-log-processors/src/main/java/org/apache/nifi/processors/windows/event/log/jna/EventSubscribeXmlRenderingCallback.java
---
@@ -0,0 +1,100 @@
+/*
+ * 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.processors.windows.event.log.jna;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.sun.jna.Memory;
+import com.sun.jna.platform.win32.Kernel32;
+import com.sun.jna.platform.win32.W32Errors;
+import com.sun.jna.platform.win32.WinDef;
+import com.sun.jna.platform.win32.WinNT;
+import org.apache.commons.io.Charsets;
+import org.apache.nifi.logging.ComponentLog;
+
+import java.util.function.Consumer;
+
+/**
+ * Callback that will render the XML representation of the event using
native Windows API
+ */
+public class EventSubscribeXmlRenderingCallback implements
WEvtApi.EVT_SUBSCRIBE_CALLBACK {
+ public static final String RECEIVED_THE_FOLLOWING_WIN32_ERROR =
"Received the following Win32 error: ";
+ public static final int INITIAL_BUFFER_SIZE = 1024;
+
+ private final ComponentLog logger;
+ private final Consumer<String> consumer;
+ private final int maxBufferSize;
+ private final WEvtApi wEvtApi;
+ private final Kernel32 kernel32;
+
+ private int size;
+ private Memory buffer;
+ private Memory used;
+ private Memory propertyCount;
+
+ public EventSubscribeXmlRenderingCallback(ComponentLog logger,
Consumer<String> consumer, int maxBufferSize, WEvtApi wEvtApi, Kernel32
kernel32) {
+ this.logger = logger;
+ this.consumer = consumer;
+ this.maxBufferSize = maxBufferSize;
+ this.wEvtApi = wEvtApi;
+ this.kernel32 = kernel32;
+ this.size = Math.min(maxBufferSize, INITIAL_BUFFER_SIZE);
+ this.buffer = new Memory(size);
+ this.used = new Memory(4);
+ this.propertyCount = new Memory(4);
+ }
+
+ @Override
+ public synchronized int onEvent(int evtSubscribeNotifyAction,
WinDef.PVOID userContext, WinNT.HANDLE eventHandle) {
--- End diff --
Whelp can't really do anything about bad api's. At the very least a comment
should be added explaining it for future maintainers
> JNA-Based Event Log Subscription Processor
> ------------------------------------------
>
> Key: NIFI-1976
> URL: https://issues.apache.org/jira/browse/NIFI-1976
> Project: Apache NiFi
> Issue Type: Sub-task
> Reporter: Bryan Rosander
>
> Using JNA, we should be able to leverage existing Windows APIs to natively
> consume events as they happen. Will look into subscribing to events
> (https://msdn.microsoft.com/en-us/library/windows/desktop/aa385771(v=vs.85).aspx)
> in order to reduce latency.
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