Split or move libraries-apache-commons module (#7873)

libraries-apache-commons-io/README.md

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+## Apache Commons Collections
+
+This module contains articles about Apache Commons IO
+
+### Relevant articles
+- [Apache Commons IO](https://www.baeldung.com/apache-commons-io)
+- [Introduction to Apache Commons CSV](https://www.baeldung.com/apache-commons-csv)

libraries-apache-commons-io/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>libraries-apache-commons-io</artifactId>
+    <name>libraries-apache-commons-io</name>
+
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-csv</artifactId>
+            <version>${commons-csv.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <commons-csv.version>1.4</commons-csv.version>
+    </properties>
+
+</project>

libraries-apache-commons-io/src/main/java/com/baeldung/commons/io/FileMonitor.java

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+package com.baeldung.commons.io;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.monitor.FileAlterationListener;
+import org.apache.commons.io.monitor.FileAlterationListenerAdaptor;
+import org.apache.commons.io.monitor.FileAlterationMonitor;
+import org.apache.commons.io.monitor.FileAlterationObserver;
+
+import java.io.File;
+
+public class FileMonitor {
+
+    public static void main(String[] args) throws Exception {
+        File folder = FileUtils.getTempDirectory();
+        startFileMonitor(folder);
+    }
+
+    /**
+     * @param folder
+     * @throws Exception
+     */
+    public static void startFileMonitor(File folder) throws Exception {
+        FileAlterationObserver observer = new FileAlterationObserver(folder);
+        FileAlterationMonitor monitor = new FileAlterationMonitor(5000);
+
+        FileAlterationListener fal = new FileAlterationListenerAdaptor() {
+
+            @Override
+            public void onFileCreate(File file) {
+                // on create action
+            }
+
+            @Override
+            public void onFileDelete(File file) {
+                // on delete action
+            }
+        };
+
+        observer.addListener(fal);
+        monitor.addObserver(observer);
+        monitor.start();
+    }
+}

libraries-apache-commons-io/src/test/java/com/baeldung/commons/io/CommonsIOUnitTest.java

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+package com.baeldung.commons.io;
+
+import org.apache.commons.io.FileSystemUtils;
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.FilenameUtils;
+import org.apache.commons.io.IOCase;
+import org.apache.commons.io.comparator.PathFileComparator;
+import org.apache.commons.io.comparator.SizeFileComparator;
+import org.apache.commons.io.filefilter.AndFileFilter;
+import org.apache.commons.io.filefilter.NameFileFilter;
+import org.apache.commons.io.filefilter.SuffixFileFilter;
+import org.apache.commons.io.filefilter.WildcardFileFilter;
+import org.apache.commons.io.input.TeeInputStream;
+import org.apache.commons.io.output.TeeOutputStream;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FilterOutputStream;
+import java.io.IOException;
+import java.nio.charset.Charset;
+
+public class CommonsIOUnitTest {
+
+    @Test
+    public void whenCopyANDReadFileTesttxt_thenMatchExpectedData() throws IOException {
+
+        String expectedData = "Hello World from fileTest.txt!!!";
+
+        File file = FileUtils.getFile(getClass().getClassLoader().getResource("fileTest.txt").getPath());
+        File tempDir = FileUtils.getTempDirectory();
+        FileUtils.copyFileToDirectory(file, tempDir);
+        File newTempFile = FileUtils.getFile(tempDir, file.getName());
+        String data = FileUtils.readFileToString(newTempFile, Charset.defaultCharset());
+
+        Assert.assertEquals(expectedData, data.trim());
+    }
+
+    @Test
+    public void whenUsingFileNameUtils_thenshowdifferentFileOperations() throws IOException {
+
+        String path = getClass().getClassLoader().getResource("fileTest.txt").getPath();
+
+        String fullPath = FilenameUtils.getFullPath(path);
+        String extension = FilenameUtils.getExtension(path);
+        String baseName = FilenameUtils.getBaseName(path);
+
+        System.out.println("full path" + fullPath);
+        System.out.println("Extension" + extension);
+        System.out.println("Base name" + baseName);
+    }
+
+    @Test
+    public void whenUsingFileSystemUtils_thenDriveFreeSpace() throws IOException {
+
+        long freeSpace = FileSystemUtils.freeSpaceKb("/");
+    }
+
+    @SuppressWarnings("resource")
+    @Test
+    public void whenUsingTeeInputOutputStream_thenWriteto2OutputStreams() throws IOException {
+
+        final String str = "Hello World.";
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(str.getBytes());
+        ByteArrayOutputStream outputStream1 = new ByteArrayOutputStream();
+        ByteArrayOutputStream outputStream2 = new ByteArrayOutputStream();
+
+        FilterOutputStream teeOutputStream = new TeeOutputStream(outputStream1, outputStream2);
+        new TeeInputStream(inputStream, teeOutputStream, true).read(new byte[str.length()]);
+
+        Assert.assertEquals(str, String.valueOf(outputStream1));
+        Assert.assertEquals(str, String.valueOf(outputStream2));
+    }
+
+    @Test
+    public void whenGetFilewithNameFileFilter_thenFindfileTesttxt() throws IOException {
+
+        final String testFile = "fileTest.txt";
+
+        String path = getClass().getClassLoader().getResource(testFile).getPath();
+        File dir = FileUtils.getFile(FilenameUtils.getFullPath(path));
+
+        String[] possibleNames = { "NotThisOne", testFile };
+
+        Assert.assertEquals(testFile, dir.list(new NameFileFilter(possibleNames, IOCase.INSENSITIVE))[0]);
+    }
+
+    @Test
+    public void whenGetFilewith_ANDFileFilter_thenFindsampletxt() throws IOException {
+
+        String path = getClass().getClassLoader().getResource("fileTest.txt").getPath();
+        File dir = FileUtils.getFile(FilenameUtils.getFullPath(path));
+
+        Assert.assertEquals("sample.txt", dir.list(new AndFileFilter(new WildcardFileFilter("*ple*", IOCase.INSENSITIVE), new SuffixFileFilter("txt")))[0]);
+    }
+
+    @Test
+    public void whenSortDirWithPathFileComparator_thenFirstFileaaatxt() throws IOException {
+
+        PathFileComparator pathFileComparator = new PathFileComparator(IOCase.INSENSITIVE);
+        String path = FilenameUtils.getFullPath(getClass().getClassLoader().getResource("fileTest.txt").getPath());
+        File dir = new File(path);
+        File[] files = dir.listFiles();
+
+        pathFileComparator.sort(files);
+
+        Assert.assertEquals("aaa.txt", files[0].getName());
+    }
+
+    @Test
+    public void whenSizeFileComparator_thenLargerFile() throws IOException {
+
+        SizeFileComparator sizeFileComparator = new SizeFileComparator();
+        File largerFile = FileUtils.getFile(getClass().getClassLoader().getResource("fileTest.txt").getPath());
+        File smallerFile = FileUtils.getFile(getClass().getClassLoader().getResource("sample.txt").getPath());
+
+        int i = sizeFileComparator.compare(largerFile, smallerFile);
+
+        Assert.assertTrue(i > 0);
+    }
+}

libraries-apache-commons-io/src/test/java/com/baeldung/commons/io/csv/CSVReaderWriterUnitTest.java

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+package com.baeldung.commons.io.csv;
+
+import org.apache.commons.csv.CSVFormat;
+import org.apache.commons.csv.CSVPrinter;
+import org.apache.commons.csv.CSVRecord;
+import org.junit.Test;
+
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.Reader;
+import java.io.StringWriter;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+public class CSVReaderWriterUnitTest {
+
+    public static final Map<String, String> AUTHOR_BOOK_MAP = Collections.unmodifiableMap(new LinkedHashMap<String, String>() {
+        {
+            put("Dan Simmons", "Hyperion");
+            put("Douglas Adams", "The Hitchhiker's Guide to the Galaxy");
+        }
+    });
+    public static final String[] HEADERS = { "author", "title" };
+    public static final String EXPECTED_FILESTREAM = "author,title\r\n" + "Dan Simmons,Hyperion\r\n" + "Douglas Adams,The Hitchhiker's Guide to the Galaxy";
+
+    @Test
+    public void givenCSVFile_whenRead_thenContentsAsExpected() throws IOException {
+        Reader in = new FileReader("src/test/resources/book.csv");
+        Iterable<CSVRecord> records = CSVFormat.DEFAULT.withHeader(HEADERS).withFirstRecordAsHeader().parse(in);
+        for (CSVRecord record : records) {
+            String author = record.get("author");
+            String title = record.get("title");
+            assertEquals(AUTHOR_BOOK_MAP.get(author), title);
+        }
+    }
+
+    @Test
+    public void givenAuthorBookMap_whenWrittenToStream_thenOutputStreamAsExpected() throws IOException {
+        StringWriter sw = new StringWriter();
+        try (final CSVPrinter printer = new CSVPrinter(sw, CSVFormat.DEFAULT.withHeader(HEADERS))) {
+            AUTHOR_BOOK_MAP.forEach((author, title) -> {
+                try {
+                    printer.printRecord(author, title);
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            });
+        }
+        assertEquals(EXPECTED_FILESTREAM, sw.toString().trim());
+    }
+
+}

libraries-apache-commons-io/src/test/resources/aaa.txt

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+Hello World from aaa.txt!!!

libraries-apache-commons-io/src/test/resources/book.csv

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+author,title
+Dan Simmons,Hyperion
+Douglas Adams,The Hitchhiker's Guide to the Galaxy

libraries-apache-commons-io/src/test/resources/fileTest.txt

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+Hello World from fileTest.txt!!!

libraries-apache-commons-io/src/test/resources/sample.txt

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+line 1
+a second line