io operation

src/main/java/com/examplehub/basics/io/BufferInputStreamExample.java

@@ -0,0 +1,4 @@
+package com.examplehub.basics.io;
+
+public class BufferInputStreamExample {
+}

src/main/java/com/examplehub/basics/io/BufferReaderExample.java

@@ -0,0 +1,4 @@
+package com.examplehub.basics.io;
+
+public class BufferReaderExample {
+}

src/main/java/com/examplehub/basics/io/DataInputStreamExample.java

@@ -0,0 +1,5 @@
+package com.examplehub.basics.io;
+
+public class DataInputStreamExample {
+
+}

src/main/java/com/examplehub/basics/io/DataOutputStreamExample.java

@@ -0,0 +1,4 @@
+package com.examplehub.basics.io;
+
+public class DataOutputStreamExample {
+}

src/main/java/com/examplehub/basics/io/PrintStreamExample.java

@@ -0,0 +1,4 @@
+package com.examplehub.basics.io;
+
+public class PrintStreamExample {
+}

src/test/java/com/examplehub/basics/io/BufferInputStreamExampleTest.java

@@ -0,0 +1,28 @@
+package com.examplehub.basics.io;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BufferInputStreamExampleTest {
+  @Test
+  void testCopyFile() throws IOException {
+    String filename = "pom.xml";
+    String newFileName = "pom_bk.xml";
+    try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream(filename));
+         BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(newFileName))) {
+      byte[] buffer = new byte[1024];
+      int readBytes;
+      while ((readBytes = bis.read(buffer)) != -1) {
+        bos.write(buffer, 0, readBytes);
+        bos.flush();
+      }
+      assertEquals(new File(filename).length(), new File(newFileName).length());
+    }
+    assertTrue(Files.deleteIfExists(Paths.get(newFileName)));
+  }
+}

src/test/java/com/examplehub/basics/io/BufferReaderExampleTest.java

@@ -0,0 +1,32 @@
+package com.examplehub.basics.io;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BufferReaderExampleTest {
+  @Test
+  void testCopyFile() throws IOException {
+    String filename = "pom.xml";
+    String newFileName = "pom_bk.xml";
+    try (BufferedReader bufferedReader = new BufferedReader(new FileReader(filename));
+         BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(newFileName))) {
+      String line = bufferedReader.readLine();
+      while (line != null) {
+        String nextLine = bufferedReader.readLine();
+        bufferedWriter.write(line);
+        if (nextLine != null) {
+          bufferedWriter.write(System.lineSeparator());
+        }
+        bufferedWriter.flush();
+        line = nextLine;
+      }
+      assertEquals(new File(filename).length(), new File(newFileName).length());
+    }
+    assertTrue(Files.deleteIfExists(Paths.get(newFileName)));
+  }
+}

src/test/java/com/examplehub/basics/io/CreateFolderTest.java

@@ -2,6 +2,9 @@
 
 import static org.junit.jupiter.api.Assertions.*;
 
+
+import com.examplehub.basics.io.CreateFolder;
+
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 

src/test/java/com/examplehub/basics/io/DataInputStreamExampleTest.java

@@ -0,0 +1,24 @@
+package com.examplehub.basics.io;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class DataInputStreamExampleTest {
+  @Test
+  void testRead() throws IOException {
+    String filename = "example.txt";
+    try (DataOutputStream dataOutputStream = new DataOutputStream(new FileOutputStream(filename));
+         DataInputStream dataInputStream = new DataInputStream(new FileInputStream(filename))) {
+      dataOutputStream.writeInt(97);
+      dataOutputStream.flush();
+
+      assertEquals(97, dataInputStream.readInt());
+    }
+    assertTrue(Files.deleteIfExists(Paths.get(filename)));
+  }
+}

src/test/java/com/examplehub/basics/io/DataOutputStreamExampleTest.java

@@ -0,0 +1,22 @@
+package com.examplehub.basics.io;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.DataOutputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class DataOutputStreamExampleTest {
+  @Test
+  void testWriteInt() throws IOException {
+    String filename = "example.txt";
+    try(DataOutputStream dataOutputStream = new DataOutputStream(new FileOutputStream(filename))) {
+      dataOutputStream.writeInt(97);
+    }
+    assertTrue(Files.deleteIfExists(Paths.get(filename)));
+  }
+}

src/test/java/com/examplehub/basics/io/FileExampleTest.java

@@ -68,7 +68,7 @@ void testIsDirectory() {
 
   @Test
   void testCreateDelete() throws IOException {
-    File file = new File("example.txt");
+    File file = new File("demo.txt");
     assertTrue(file.createNewFile());
     assertTrue(file.delete());
   }

src/test/java/com/examplehub/basics/io/FileOutputStreamExampleTest.java

@@ -4,6 +4,9 @@
 
 import java.io.*;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
 import org.junit.jupiter.api.Test;
 
 class FileOutputStreamExampleTest {
@@ -40,8 +43,8 @@ void testCopyFile() throws IOException {
       while ((readBytes = inputStream.read(bytes)) != -1) {
         outputStream.write(bytes, 0, readBytes);
       }
+      assertEquals(new File(srcPath).length(), new File(destPath).length());
     }
-
-    assertTrue(DeleteFile.deleteFile("pom.xml.bk"));
+    Files.deleteIfExists(Paths.get(destPath));
   }
 }

src/test/java/com/examplehub/basics/io/FileReaderExampleTest.java

@@ -1,33 +1,81 @@
 package com.examplehub.basics.io;
 
 import com.examplehub.utils.StringUtils;
-import java.io.FileReader;
-import java.io.IOException;
-import java.io.Reader;
-import java.nio.charset.StandardCharsets;
 import org.junit.jupiter.api.Test;
 
+import java.io.*;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 class FileReaderExampleTest {
+
   @Test
-  void testReadChar() throws IOException {
-    try (Reader reader = new FileReader("pom.xml", StandardCharsets.UTF_8)) {
+  void testReadSingleChar() throws IOException {
+    String filename = "example.txt";
+    try (Writer writer = new FileWriter(filename)) {
+      writer.write("Java");
+    }
+    try (Reader reader = new FileReader(filename)) {
+      assertEquals('J', reader.read());
+      assertEquals('a', reader.read());
+      assertEquals('v', reader.read());
+      assertEquals('a', reader.read());
+      assertEquals(-1, reader.read());
+    }
+    Files.deleteIfExists(Paths.get(filename));
+  }
+
+  @Test
+  void testReadChars() throws IOException {
+    String filename = "example.txt";
+    try (Writer writer = new FileWriter(filename)) {
+      writer.write("Java");
+    }
+    try (Reader reader = new FileReader(filename, StandardCharsets.UTF_8)) {
+      char[] letter = new char[4];
+      int index = 0;
       int ch;
       while ((ch = reader.read()) != -1) {
-        System.out.print((char) ch);
+        letter[index++] = (char) ch;
       }
-    } finally {
-      System.out.println("read completed");
+      assertEquals("Java", new String(letter));
     }
   }
 
   @Test
-  void testReadChars() throws IOException {
-    try (Reader reader = new FileReader("pom.xml", StandardCharsets.UTF_8)) {
+  void testReadCharsToArray() throws IOException {
+    String filename = "example.txt";
+    try (Writer writer = new FileWriter(filename)) {
+      writer.write("I love\n");
+      writer.write("Java");
+    }
+    try (Reader reader = new FileReader(filename, StandardCharsets.UTF_8)) {
       char[] buffer = new char[1024];
-      int len = 0;
+      int len;
+      StringBuilder builder = new StringBuilder();
       while ((len = reader.read(buffer)) != -1) {
-        System.out.print(StringUtils.toString(buffer, 0, len));
+        builder.append(StringUtils.toString(buffer, 0, len));
+      }
+      assertEquals("I love\nJava", builder.toString());
+    }
+  }
+
+  @Test
+  void testCopyCharacterFile() throws IOException {
+    String filename = "pom.xml";
+    String newFile = "pom_bk.xml";
+    try (Writer writer = new FileWriter(newFile); Reader reader = new FileReader(filename)) {
+      int ch;
+      while ((ch = reader.read()) != -1) {
+        writer.write(ch);
       }
+      writer.flush();
+      assertEquals(new File(filename).length(), new File(newFile).length());
+    }finally {
+      Files.deleteIfExists(Paths.get(newFile));
     }
   }
 }

src/test/java/com/examplehub/basics/io/FileWriterExampleTest.java

@@ -17,6 +17,39 @@ void testWrite() throws IOException {
       writer.write("hello");
     }
     assertEquals("hello", FileReaderExample.read(fileName));
-    Files.deleteIfExists(Paths.get("example.txt"));
+    Files.deleteIfExists(Paths.get(fileName));
+  }
+
+  @Test
+  void testWriteSingleChar() throws IOException{
+    String fileName = "example.txt";
+    try (Writer writer = new FileWriter(fileName)) {
+      writer.write('A');
+      writer.write(66); //write B
+    }
+    assertEquals("AB", FileReaderExample.read(fileName));
+    Files.deleteIfExists(Paths.get(fileName));
+  }
+
+  @Test
+  void testWriteCharArray() throws IOException{
+    char[] letters = {'J', 'a', 'v', 'a'};
+    String fileName = "example.txt";
+    try (Writer writer = new FileWriter(fileName)) {
+      writer.write(letters);
+    }
+    assertEquals("Java", FileReaderExample.read(fileName));
+    Files.deleteIfExists(Paths.get(fileName));
+  }
+
+  @Test
+  void testWriteOnesOfCharArray() throws IOException{
+    char[] letters = {'J', 'a', 'v', 'a'};
+    String fileName = "example.txt";
+    try (Writer writer = new FileWriter(fileName)) {
+      writer.write(letters, 1, 2);
+    }
+    assertEquals("av", FileReaderExample.read(fileName));
+    Files.deleteIfExists(Paths.get(fileName));
   }
 }

src/test/java/com/examplehub/basics/io/PrintStreamExampleTest.java

@@ -0,0 +1,22 @@
+package com.examplehub.basics.io;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.io.PrintStream;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class PrintStreamExampleTest {
+  @Test
+  void testPrint() throws IOException {
+    String filename = "example.txt";
+    PrintStream printStream = new PrintStream(filename);
+    printStream.write("Java".getBytes(StandardCharsets.UTF_8));
+    assertEquals("Java", FileReaderExample.read(filename));
+    assertTrue(Files.deleteIfExists(Paths.get(filename)));
+  }
+}

src/test/java/com/examplehub/basics/io/RecursionPrintDirectoryTest.java

@@ -1,9 +1,10 @@
 package com.examplehub.basics.io;
 
-import java.io.File;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
+import java.io.File;
+
 class RecursionPrintDirectoryTest {
 
   @Test