DouKaku?

#!/usr/local/bin/perl
use strict;
use warnings;
use Regexp::Assemble;

my $ra = Regexp::Assemble->new;
while(<>){
    chomp;
    next unless $_;
    $ra->add($_);
}
print $ra->re, "\n"
__END__

% grep program /usr/share/dict/words 
program
programist
programistic
programma
programmar
programmatic
programmatically
programmatist
programmer

% grep program /usr/share/dict/words | perl sample.pl 
(?-xism:program(?:m(?:a(?:ti(?:c(?:ally)?|st)|r)?|er)|ist(?:ic)?)?)

import java.util.*;

@SuppressWarnings("unckecked")
public class Trie {
    public static final String MUST_ESCAPE = "()[]\\.+*?|";
    private Map<Character, Map> trie = new TreeMap<Character, Map>();
    public void add(String str) {
        Map<Character, Map> t = trie;
        for (char c : str.toCharArray()) {
            if (t.containsKey(c)) {
                t = (Map<Character, Map>)t.get(c);
            } else {
                Map<Character, Map> t2 = new TreeMap<Character, Map>();
                t.put(c, t2);
                t = t2;
            }
        }
        t.put('\0', null);
    }
    public String toRegex() {
        return toRegex(trie).toString();
    }
    private StringBuilder toRegex(Map<Character, Map> t) {
        StringBuilder sb = new StringBuilder();
        Set<Character> keys = t.keySet();
        if (keys.size() > 1)
            sb.append("(?:");
        Iterator<Character> i = keys.iterator();
        while (i.hasNext()) {
            char c = i.next();
            if (c != '\0') {
                if (MUST_ESCAPE.indexOf(c) >= 0)
                    sb.append('\\');
                sb.append(c);
                sb.append(toRegex(t.get(c)));
            }
            if (i.hasNext())
                sb.append('|');
        }
        if (keys.size() > 1)
            sb.append(")");
        return sb;
    }
    public static void main(String[] args) {
        Trie t = new Trie();
        for (String str : args) {
            t.add(str);
        }
        System.out.println(t.toRegex());
    }
}