The program needs to read in a text file and display the contents of the file to

Question

The program needs to read in a text file and display the contents of the file to the screen output. The file will

contain words separated by spaces, lines terminated by the newline character(s), and

paragraphs separated by a blank line (i.e., a line with zero (0) characters in it).

Your task is to write the program Format which will take a single command line argument to

specify the width of the output line. The name of the file to be formatted will be entered as

redirected standard input. The output will be displayed to the standard output (i.e., the screen).

To read from a disk file you will need to import the classes java.util.Scanner.

To create a Scanner class object instance for the redirected standard input (the file to be

formatted) include the following lines:

Scanner input = new Scanner(System.in);

Your program will read from the scanner input a line at a time. For each line read, if the line

has a zero (0) length then just display a blank line. Otherwise, the line will contain words.

Create a new Scanner object instance whose constructor takes the name of the String that

contains the line you just read in. You can then pick up each word using the next() method.

You will need a StringBuilder object instance to hold the output line that you are building up.

You then append words to the end of the output StringBuilder. Remember to add a single

blank space between each word (but not before the first word in the output StringBuilder).

Before adding a word you should check that the current length of the string plus the length of

the new word and the blank space does not exceed the output line width that the user specified

at the beginning of the execution of the program. If the new word will cause the output string to

become too long then the unaugmented line will be displayed, the output line StringBuilder

should be cleared (reset to have 0 length) and the new word added to the empty string. Be

aware that when the file is completely read there might be some words left in the output

StringBuilder. These should also be displayed to the screen. Close all scanners when they

have completed their tasks.

You should include some statistics gathering and display to your program. Keep track of the

number of lines and words read in as well as the number of lines and words displayed.

I am including two text files with this project. The first is the text of the Declaration of

Independence (DoI.txt). This file will serve as the input file to the formatting program. The

second is the result of running the program (DoI.fmt). You should use these files to guide you

in developing the program.

Explanation / Answer

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.IOException;

import java.nio.charset.Charset;

import java.nio.charset.StandardCharsets;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.Arrays;

import java.util.List;

import java.util.Scanner;

public class ReadWriteTextFileJDK7 {

public static void main(String... aArgs) throws IOException{

ReadWriteTextFileJDK7 text = new ReadWriteTextFileJDK7();

//treat as a small file

List<String> lines = text.readSmallTextFile(FILE_NAME);

log(lines);

lines.add("This is a line added in code.");

text.writeSmallTextFile(lines, FILE_NAME);

//treat as a large file - use some buffering

text.readLargerTextFile(FILE_NAME);

lines = Arrays.asList("Down to the Waterline", "Water of Love");

text.writeLargerTextFile(OUTPUT_FILE_NAME, lines);

}

final static String FILE_NAME = "C:\Temp\input.txt";

final static String OUTPUT_FILE_NAME = "C:\Temp\output.txt";

final static Charset ENCODING = StandardCharsets.UTF_8;

//For smaller files

List<String> readSmallTextFile(String aFileName) throws IOException {

Path path = Paths.get(aFileName);

return Files.readAllLines(path, ENCODING);

}

void writeSmallTextFile(List<String> aLines, String aFileName) throws IOException {

Path path = Paths.get(aFileName);

Files.write(path, aLines, ENCODING);

}

//For larger files

void readLargerTextFile(String aFileName) throws IOException {

Path path = Paths.get(aFileName);

try (Scanner scanner = new Scanner(path, ENCODING.name())){

while (scanner.hasNextLine()){

//process each line in some way

log(scanner.nextLine());

}

}

}

void readLargerTextFileAlternate(String aFileName) throws IOException {

Path path = Paths.get(aFileName);

try (BufferedReader reader = Files.newBufferedReader(path, ENCODING)){

String line = null;

while ((line = reader.readLine()) != null) {

//process each line in some way

log(line);

}

}

}

void writeLargerTextFile(String aFileName, List<String> aLines) throws IOException {

Path path = Paths.get(aFileName);

try (BufferedWriter writer = Files.newBufferedWriter(path, ENCODING)){

for(String line : aLines){

writer.write(line);

writer.newLine();

}

}

}

private static void log(Object aMsg){

System.out.println(String.valueOf(aMsg));

}

}

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