com.signalfx.shaded.apache.commons.io.filefilter.SymbolicLinkFileFilter Maven / Gradle / Ivy
/*
* 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 com.signalfx.shaded.apache.commons.io.filefilter;
import java.io.File;
import java.io.Serializable;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
/**
* This filter accepts {@link File}s that are symbolic links.
*
* For example, here is how to print out a list of the real files
* within the current directory:
*
* Using Classic IO
*
* File dir = FileUtils.current();
* String[] files = dir.list(SymbolicLinkFileFilter.INSTANCE);
* for (String file : files) {
* System.out.println(file);
* }
*
*
* Using NIO
*
* final Path dir = PathUtils.current();
* final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(SymbolicLinkFileFilter.INSTANCE);
* //
* // Walk one dir
* Files.walkFileTree(dir, Collections.emptySet(), 1, visitor);
* System.out.println(visitor.getPathCounters());
* System.out.println(visitor.getFileList());
* //
* visitor.getPathCounters().reset();
* //
* // Walk dir tree
* Files.walkFileTree(dir, visitor);
* System.out.println(visitor.getPathCounters());
* System.out.println(visitor.getDirList());
* System.out.println(visitor.getFileList());
*
* Deprecating Serialization
*
* Serialization is deprecated and will be removed in 3.0.
*
*
* @since 2.11.0
* @see FileFilterUtils#fileFileFilter()
*/
public class SymbolicLinkFileFilter extends AbstractFileFilter implements Serializable {
/*
* Note to developers: The unit test needs to create symbolic links to files. However, on
* Windows, this can't be done without admin privileges. This class is designed to allow a
* unit test to works around this by doing two things: 1) This separates the class logic from
* the call to identify a symbolic link, and 2) It allows the unit test to override that
* symbolic link call on Windows only.
* This means we can write unit tests will run on all machines. On Windows, the unit test
* can't create a symbolic link without admin privileges, so the unit tests won't
* completely test all the necessary behavior on Windows, but they will still test the class
* logic. Be careful not to break this, but be aware of it when writing unit tests. You can
* still maintain this class and its unit tests on Windows. The one method that won't get
* tested on Windows is not likely to change, and will be tested properly when it gets run
* on Apache servers.
*/
/**
* Singleton instance of file filter.
*/
public static final SymbolicLinkFileFilter INSTANCE = new SymbolicLinkFileFilter();
private static final long serialVersionUID = 1L;
/**
* Restrictive constructor.
*/
protected SymbolicLinkFileFilter() {
}
/**
* Constructs a new instance.
*
* @param onAccept What to do on acceptance.
* @param onReject What to do on rejection.
* @since 2.12.0.
*/
public SymbolicLinkFileFilter(final FileVisitResult onAccept, final FileVisitResult onReject) {
super(onAccept, onReject);
}
/**
* Checks to see if the file is a symbolic link.
*
* @param file the File to check
* @return true if the file exists and is a symbolic link to either another file or a directory,
* false otherwise.
*/
@Override
public boolean accept(final File file) {
return isSymbolicLink(file.toPath());
}
/**
* Checks to see if the file is a file.
*
* @param path the File Path to check
* @return true if the file exists and is a symbolic link to either another file or a directory.
*/
@Override
public FileVisitResult accept(final Path path, final BasicFileAttributes attributes) {
return toFileVisitResult(isSymbolicLink(path));
}
/**
* Delegates to {@link Files#isSymbolicLink(Path)} for testing.
*
* Using package access for unit tests. To facilitate unit testing, all calls to test if the file is a symbolic should go through this method. (See the unit
* test for why.)
*
*
* @param filePath The filePath to test
* @return true if the file exists and is a symbolic link to either a file or directory, false otherwise.
*/
boolean isSymbolicLink(final Path filePath) {
return Files.isSymbolicLink(filePath);
}
}