KTLN-864 Delete content of a file (#986)

* KTLN-864 Delete content of a file

* Test file name change

Author: thebaubau

core-kotlin-modules/core-kotlin-io/pom.xml

@@ -13,4 +13,12 @@
         <version>1.0.0-SNAPSHOT</version>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>2.15.1</version>
+        </dependency>
+    </dependencies>
+
 </project>

core-kotlin-modules/core-kotlin-io/src/main/kotlin/com/baeldung/deleteFileContent/DeleteFileContent.kt

@@ -0,0 +1,45 @@
+package com.baeldung.deleteFileContent
+
+import org.apache.commons.io.FileUtils
+import java.io.*
+import java.nio.channels.FileChannel
+import java.nio.file.Files
+import java.nio.file.StandardOpenOption
+
+class DeleteFileContent {
+    fun withWriteText(file: File) {
+        file.writeText("")
+    }
+
+    fun withFileWriter(file: File) {
+        FileWriter(file).close()
+    }
+
+    fun withPrintWriter(file: File) {
+        PrintWriter(file).close()
+    }
+
+    fun withFileOutputStream(file: File) {
+        FileOutputStream(file).close()
+    }
+
+    fun withBufferedWriter(file: File) {
+        BufferedWriter(FileWriter(file)).close()
+    }
+
+    fun withRandomAccessFile(file: File) {
+        RandomAccessFile(file, "rw").setLength(0)
+    }
+
+    fun withFileChannel(file: File) {
+        FileChannel.open(file.toPath(), StandardOpenOption.WRITE).truncate(0).close()
+    }
+
+    fun withFiles(file: File) {
+        Files.write(file.toPath(), byteArrayOf(), StandardOpenOption.TRUNCATE_EXISTING)
+    }
+
+    fun withFileUtils(file: File) {
+        FileUtils.write(file, "", Charsets.UTF_8)
+    }
+}

core-kotlin-modules/core-kotlin-io/src/test/kotlin/com/baeldung/deleteFileContent/DeleteFileContentUnitTest.kt

@@ -0,0 +1,95 @@
+package com.baeldung.deleteFileContent
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import java.io.File
+
+class DeleteFileContentUnitTest {
+    private val fileName = "src/test/resources/example.txt"
+
+    private val deleteFileContent = DeleteFileContent()
+
+    @BeforeEach
+    fun setUp() {
+        File(fileName).writeText("Hello, World!")
+    }
+
+    @AfterEach
+    fun tearDown() {
+        File(fileName).delete()
+    }
+
+    @Test
+    fun `Delete content with writeText`() {
+        val file = File(fileName)
+        deleteFileContent.withWriteText(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+
+    @Test
+    fun `Delete content with FileWriter`() {
+        val file = File(fileName)
+        deleteFileContent.withFileWriter(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+
+    @Test
+    fun `Delete content with PrintWriter`() {
+        val file = File(fileName)
+        deleteFileContent.withPrintWriter(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+
+    @Test
+    fun withFileOutputStream() {
+        val file = File(fileName)
+        deleteFileContent.withFileOutputStream(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+
+    @Test
+    fun withBufferedWriter() {
+        val file = File(fileName)
+        deleteFileContent.withBufferedWriter(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+
+    @Test
+    fun withRandomAccessFile() {
+        val file = File(fileName)
+        deleteFileContent.withRandomAccessFile(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+
+    @Test
+    fun withFileChannel() {
+        val file = File(fileName)
+        deleteFileContent.withFileChannel(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+
+    @Test
+    fun withFiles() {
+        val file = File(fileName)
+        deleteFileContent.withFiles(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+
+    @Test
+    fun withFileUtils() {
+        val file = File(fileName)
+        deleteFileContent.withFileUtils(file)
+
+        assertThat(file.readText()).isEmpty()
+    }
+}