Description:

This program describes the way to calculate the Repeating word from the file using Regular expression. This program declares the file path and its name from where the words are to be counted. It uses ISO-8859-1 character set, which is used for creating decoders and encoders. FileInputStream class creates a file input stream and gets input bytes from a file. get Channel () creates object of FileChannel that is associated with the file input stream.

MappedByteBuffer is a buffer whose data is memory mapped with the file. A matcher is created from a pattern by invoking the pattern’s matcher method. Split (CharacterSequence) method splits the given input sequence around matches of this pattern.

Calculating Repetingwords of a file Using Java:

import java.io.FileInputStream; import java.nio.CharBuffer; import java.nio.MappedByteBuffer; import java.nio.channels.FileChannel; import java.nio.charset.Charset; import java.nio.charset.CharsetDecoder; import java.util.Map; import java.util.TreeMap; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Calculatingword { public static void main(String args[]) throws Exception { String file = "/Sample/ex.txt"; FileInputStream inputStream = new FileInputStream(file); FileChannel fileChannel = inputStream.getChannel(); //System.out.println(fileChannel); int fileLength = (int) fileChannel.size(); MappedByteBuffer mbb = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, fileLength); Charset charset = Charset.forName("ISO-8859-1"); CharsetDecoder cd = charset.newDecoder(); CharBuffer charBuffer = cd.decode(mbb); System.out.println("===========" + "The words of given file are =========="); System.out.println(charBuffer); System.out.println("========================" + "==================================="); Pattern pattern = Pattern.compile(".*$", Pattern.MULTILINE); Pattern patternword = Pattern.compile("[\\p{Punct}\\s}]"); Matcher Lmatcher = pattern.matcher(charBuffer); Map map = new TreeMap(); Integer one = new Integer(1); while (Lmatcher.find()) { CharSequence sequence = Lmatcher.group(); String word[] = patternword.split(sequence); for (int i = 0, n = word.length; i < n; i++) { if (word[i].length() > 0) { Integer times = (Integer) map.get(word[i]); if (times == null) { times =one; } else { int value = times.intValue(); times = new Integer(value + 1); } map.put(word[i], times); } } } System.out.println("No of times words repeted are :"+"\n"+map); } }