Words in a text are always a source of randomness. Given a certain word, nothing can be inferred about the next word. For each word, we can take the ASCII codes of its letters, add those codes to form a number. The parity of this number is a good candidate for a random boolean.
Possible drawbacks:
this strategy is based upon using a text file as a source for the words. At some point, the end of the file will be reached. However, you can estimate how many times you are expected to call the randomBoolean() function from your app. If you will need to call it about 1 million times, then a text file with 1 million words will be enough. As a correction, you can use a stream of data from a live source like an online newspaper.
using some statistical analysis of the common phrases and idioms in a language, one can estimate the next word in a phrase, given the first words of the phrase, with some degree of accuracy. But statistically, these cases are rare, when we can accuratelly predict the next word. So, in most cases, the next word is independent on the previous words.
package p01;
import java.io.File; import java.nio.file.Files; import java.nio.file.Paths;
public class Main {
String words[];
int currentIndex=0;
public static String readFileAsString()throws Exception
{
String data = "";
File file = new File("the_comedy_of_errors");
//System.out.println(file.exists());
data = new String(Files.readAllBytes(Paths.get(file.getName())));
return data;
}
public void init() throws Exception
{
String data = readFileAsString();
words = data.split("\\t| |,|\\.|'|\\r|\\n|:");
}
public String getNextWord() throws Exception
{
if(currentIndex>words.length-1)
throw new Exception("out of words; reached end of file");
String currentWord = words[currentIndex];
currentIndex++;
while(currentWord.isEmpty())
{
currentWord = words[currentIndex];
currentIndex++;
}
return currentWord;
}
public boolean getNextRandom() throws Exception
{
String nextWord = getNextWord();
int asciiSum = 0;
for (int i = 0; i < nextWord.length(); i++){
char c = nextWord.charAt(i);
asciiSum = asciiSum + (int) c;
}
System.out.println(nextWord+"-"+asciiSum);
return (asciiSum%2==1) ;
}
public static void main(String args[]) throws Exception
{
Main m = new Main();
m.init();
while(true)
{
System.out.println(m.getNextRandom());
Thread.sleep(100);
}
}
}
In Eclipse, in the root of my project, there is a file called 'the_comedy_of_errors' (no extension) - created with File> New > File , where I pasted some content from here: http://shakespeare.mit.edu/comedy_errors/comedy_errors.1.1.html