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AnagramsCounter.java
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AnagramsCounter.java
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/**
* Advanced Programming - Assignment 2.2
* Concrete Job: Anagrams Counter
*/
import java.io.*;
import java.util.Arrays;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class AnagramsCounter extends AJob<String, String>{
private String file;
public AnagramsCounter(String file){ this.file = file; }
/**
* read this.file and returns a stream of pairs of the form (ciao(w), w)
* @return a stream of pair <ciao(w), w> for each word w into this.file
* an empty stream if file not found
*/
@Override
public Stream<Pair<String,String>> execute() {
BufferedReader buf = null;
try {
buf = new BufferedReader(new FileReader(this.file));
} catch (FileNotFoundException e) { // File not found -> return empty stream
System.out.println("Error! File "+this.file+" was not found and will not be computed");
return Stream.empty(); // doesn't compute this file, returning an empty stream
}
return buf
.lines()
.flatMap(s -> Arrays.stream(s.split(" ")))
.filter( s -> s.matches("^[a-zA-Z]{4,}$"))
.map(String::toLowerCase)
.map(s -> new Pair(ciao(s), s));
}
/**
* ciao(s) is a string having the same length of s and containing all
* the characters of s in lower case and alphabetical order.
* @param s: a string to map into its ciao
* @return the ciao of s
*/
private String ciao (String s){
return Stream
.of(s.split(""))
.sorted()
.collect(Collectors.joining());
}
@Override
public String toString() {
return "AnagramsCounter for file "+this.file;
}
}