Github user joewitt commented on a diff in the pull request:
https://github.com/apache/nifi/pull/113#discussion_r43801339
--- Diff:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/ListFile.java
---
@@ -0,0 +1,378 @@
+/*
+ * 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.standard;
+
+import org.apache.nifi.annotation.behavior.TriggerSerially;
+import org.apache.nifi.annotation.behavior.TriggerWhenEmpty;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.annotation.lifecycle.OnScheduled;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.flowfile.attributes.CoreAttributes;
+import org.apache.nifi.processor.DataUnit;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessorInitializationContext;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.util.StandardValidators;
+import org.apache.nifi.processors.standard.util.FileInfo;
+
+import java.io.File;
+import java.io.FileFilter;
+import java.io.IOException;
+import java.nio.file.FileStore;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.attribute.BasicFileAttributeView;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.nio.file.attribute.FileOwnerAttributeView;
+import java.nio.file.attribute.PosixFileAttributeView;
+import java.nio.file.attribute.PosixFilePermissions;
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.regex.Pattern;
+
+@TriggerSerially
+@TriggerWhenEmpty
+@Tags({"file", "get", "list", "ingest", "source", "filesystem"})
+@CapabilityDescription("Retrieves a listing of files from the local
filesystem. For each file that is listed, " +
+ "creates a FlowFile that represents the file so that it can be
fetched in conjunction with ListFile. This " +
+ "Processor is designed to run on Primary Node only in a cluster.
If the primary node changes, the new " +
+ "Primary Node will pick up where the previous node left off
without duplicating all of the data. Unlike " +
+ "GetFile, this Processor does not delete any data from the local
filesystem.")
+@WritesAttributes({
+ @WritesAttribute(attribute="filename", description="The name of
the file that was read from filesystem."),
+ @WritesAttribute(attribute="path", description="The path is set to
the absolute path of the file's directory " +
+ "on filesystem. For example, if the Directory property is
set to /tmp, then files picked up from " +
+ "/tmp will have the path attribute set to \"./\". If the
Recurse Subdirectories property is set to " +
+ "true and a file is picked up from /tmp/abc/1/2/3, then
the path attribute will be set to " +
+ "\"/tmp/abc/1/2/3\"."),
+ @WritesAttribute(attribute="fs.owner", description="The user that
owns the file in filesystem"),
+ @WritesAttribute(attribute="fs.group", description="The group that
owns the file in filesystem"),
+ @WritesAttribute(attribute="fs.lastModified", description="The
timestamp of when the file in filesystem was " +
+ "last modified, as milliseconds since midnight Jan 1, 1970
UTC"),
+ @WritesAttribute(attribute="fs.length", description="The number of
bytes in the file in filesystem"),
+ @WritesAttribute(attribute="fs.permissions", description="The
permissions for the file in filesystem. This " +
+ "is formatted as 3 characters for the owner, 3 for the
group, and 3 for other users. For example " +
+ "rw-rw-r--")
+})
+@SeeAlso({GetFile.class, PutFile.class})
+public class ListFile extends AbstractListProcessor<FileInfo> {
+
+ public static final PropertyDescriptor DIRECTORY = new
PropertyDescriptor.Builder()
+ .name("Input Directory")
+ .description("The input directory from which files to pull
files")
+ .required(true)
+
.addValidator(StandardValidators.createDirectoryExistsValidator(true, false))
+ .expressionLanguageSupported(true)
+ .build();
+
+ public static final PropertyDescriptor RECURSE = new
PropertyDescriptor.Builder()
+ .name("Recurse Subdirectories")
+ .description("Indicates whether to list files from
subdirectories of the directory")
+ .required(true)
+ .allowableValues("true", "false")
+ .defaultValue("true")
+ .build();
+
+ public static final PropertyDescriptor FILE_FILTER = new
PropertyDescriptor.Builder()
+ .name("File Filter")
+ .description("Only files whose names match the given regular
expression will be picked up")
+ .required(true)
+ .defaultValue("[^\\.].*")
+ .addValidator(StandardValidators.REGULAR_EXPRESSION_VALIDATOR)
+ .build();
+
+ public static final PropertyDescriptor PATH_FILTER = new
PropertyDescriptor.Builder()
+ .name("Path Filter")
+ .description("When " + RECURSE.getName() + " is true, then
only subdirectories whose path matches the given regular expression will be
scanned")
+ .required(false)
+ .addValidator(StandardValidators.REGULAR_EXPRESSION_VALIDATOR)
+ .build();
+
+
+ public static final PropertyDescriptor MIN_AGE = new
PropertyDescriptor.Builder()
+ .name("Minimum File Age")
+ .description("The minimum age that a file must be in order to
be pulled; any file younger than this amount of time (according to last
modification date) will be ignored")
+ .required(true)
+ .addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
+ .defaultValue("0 sec")
+ .build();
+
+ public static final PropertyDescriptor MAX_AGE = new
PropertyDescriptor.Builder()
+ .name("Maximum File Age")
+ .description("The maximum age that a file must be in order to
be pulled; any file older than this amount of time (according to last
modification date) will be ignored")
+ .required(false)
+
.addValidator(StandardValidators.createTimePeriodValidator(100,
TimeUnit.MILLISECONDS, Long.MAX_VALUE, TimeUnit.NANOSECONDS))
+ .build();
+
+ public static final PropertyDescriptor MIN_SIZE = new
PropertyDescriptor.Builder()
+ .name("Minimum File Size")
+ .description("The minimum size that a file must be in order to
be pulled")
+ .required(true)
+ .addValidator(StandardValidators.DATA_SIZE_VALIDATOR)
+ .defaultValue("0 B")
+ .build();
+
+ public static final PropertyDescriptor MAX_SIZE = new
PropertyDescriptor.Builder()
+ .name("Maximum File Size")
+ .description("The maximum size that a file can be in order to
be pulled")
+ .required(false)
+ .addValidator(StandardValidators.DATA_SIZE_VALIDATOR)
+ .build();
+
+ public static final PropertyDescriptor IGNORE_HIDDEN_FILES = new
PropertyDescriptor.Builder()
+ .name("Ignore Hidden Files")
+ .description("Indicates whether or not hidden files should be
ignored")
+ .allowableValues("true", "false")
+ .defaultValue("true")
+ .required(true)
+ .build();
+
+ private List<PropertyDescriptor> properties;
--- End diff --
This pattern within this context is generally safe by the contract of
processor initialization and that those items are only accessed by the
framework through the proper methods. If the developer causes them to be
unsafe then that is a problem but here it seems fine. I do not recommend
changing here nor anywhere else. Very common and safe approach. Now having
said this anytime you can get away with marking a member final it is best to do
so from a clarity (this cannot be changed) perspective.
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