package intermediate;

import static com.sandwich.koan.constant.KoanConstants.__;

import static com.sandwich.util.Assert.assertEquals;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.logging.Logger;

import com.sandwich.koan.Koan;

public class AboutFileIO {

@Koan

public void fileObjectDoesntCreateFile() {

File f = new File("foo.txt");

assertEquals(f.exists(), __);

}

@Koan

public void fileCreationAndDeletion() throws IOException {

File f = new File("foo.txt");

f.createNewFile();

assertEquals(f.exists(), __);

f.delete();

assertEquals(f.exists(), __);

}

@Koan

public void basicFileWritingAndReading() throws IOException {

File file = new File("file.txt");

FileWriter fw = new FileWriter(file);

fw.write("First line\nSecond line");

fw.flush();

fw.close();

char[] in = new char[50];

int size = 0;

FileReader fr = new FileReader(file);

size = fr.read(in);

// No flush necessary!

fr.close();

assertEquals(size, __);

assertEquals(new String(in), __);

file.delete();

}

@Koan

public void betterFileWritingAndReading() throws IOException {

File file = new File("file.txt");

file.deleteOnExit();

FileWriter fw = new FileWriter(file);

PrintWriter pw = new PrintWriter(fw);

pw.println("First line");

pw.println("Second line");

pw.close();

FileReader fr = new FileReader(file);

BufferedReader br = null;

try{

br = new BufferedReader(fr);

assertEquals(br.readLine(), __); // first line

assertEquals(br.readLine(), __); // second line

assertEquals(br.readLine(), __); // what now?

} finally {

closeStream(br); // anytime you open access to a

}

}

private void closeStream(BufferedReader br) {

if(br != null){

try{

br.close();

} catch (IOException x) {

Logger.getAnonymousLogger().severe("Unable to close reader.");

}

}

}

@Koan

public void directChainingForReadingAndWriting() throws IOException {

File file = new File("file.txt");

PrintWriter pw = new PrintWriter(file);

pw.println("1. line");

pw.println("2. line");

pw.close();

StringBuffer sb = new StringBuffer();

// Add the loop to go through the file line by line and add the line

// to the StringBuffer

assertEquals(sb.toString(), "1. line\n2. line");

}

}