atividade para desafio-06 osprogramadores.com

Anagrama.java

import java.util.TreeSet;
import java.util.ArrayList;

class Anagrama{
	static char[] aux;
        static TreeSet<String> listaPermutacao = new TreeSet<>();
	static ArrayList<Tarefa> listaTarefa = new ArrayList<>();

	public static void main(String args[]){
		
		String word = "";

		if(args.length < 1){
			System.out.println("Execute como java Anagrama 'palavra'");
			System.exit(0);
		}

		for(String in : args){
			word += "" + in;
		}

		permutacao(criandoArray(word));
	}
                  
	public static String criandoArray(String palavra){	
                String word = "";
		for(char car:palavra.toUpperCase().toCharArray()){
			if((car<=122 && car>=97) || (car<=90 && car>=60))
				word += "" + car;
			else{
				System.out.println("Caractere invalido");
				System.exit(0);
			}
		}

		return word;
	}

	
	public static void permutacao(String str) { 
	    permutacao("", str); 
	}

	private static void permutacao(String prefix, String str) {
	    int n = str.length();
	    if (n == 1 && listaPermutacao.add(prefix+str)) System.out.println(prefix+str);
	    else {
		for (int i = 0; i < n; i++)
		    listaTarefa.add(new Tarefa(prefix + str.charAt(i), str.substring(0, i) + str.substring(i+1, n),
					       listaPermutacao));
		
		for(Tarefa tar:listaTarefa)
			tar.start();
	    }
	}

}

class Tarefa extends Thread{
	String arg1, arg2;
	static TreeSet obj;

	public Tarefa(String arg1, String arg2, TreeSet ana){
		this.arg1 = arg1;
		this.arg2 = arg2;
		this.obj = ana;	
	}

	@Override	
	public void run(){
		this.permutacao(arg1,arg2);
	}

	private void permutacao(String prefix, String str) {
	    int n = str.length();
	    if (n == 1 && adicionar(prefix+str)) System.out.println(prefix+str);
            else {
	        for (int i = 0; i < n; i++)
		    permutacao(prefix + str.charAt(i), str.substring(0, i) + str.substring(i+1, n));
	    }
	}

	private synchronized boolean adicionar(String prefix){
		return obj.add(prefix);	
	}	
}