Using scanner to read phrases - parsing

Question

Hey StackOverflow Community,
So, I have this line of information from a txt file that I need to parse.
Here is an example lines:
-> date & time AC Power Insolation Temperature Wind Speed
-> mm/dd/yyyy hh:mm.ss kw W/m^2 deg F mph
Using a scanner.nextLine() gives me a String with a whole line in it, and then I pass this off into StringTokenizer, which then separates them into individual Strings using whitespace as a separator.
so for the first line it would break up into:
date
&
time
AC
Power
Insolation
etc...
I need things like "date & time" together, and "AC Power" together. Is there anyway I can specify this using a method already defined in StringTokenizer or Scanner? Or would I have to develop my own algorithm to do this?
Would you guys suggest I use some other form of parsing lines instead of Scanner? Or, is Scanner sufficient enough for my needs?
ejay

Answer 1

oh, this one was tricky, maybe you could build up some Trie structure with your tokens, i was bored and wrote a little class which solves your problem. Warning: it's a bit hacky, but was fun to implement.
The Trie class:
class Trie extends HashMap<String, Trie> {
private static final long serialVersionUID = 1L;
boolean end = false;
public void addToken(String strings) {
addToken(strings.split("\\s+"), 0);
}
private void addToken(String[] strings, int begin) {
if (begin == strings.length) {
end = true;
return;
}
String key = strings[begin];
Trie t = get(key);
if (t == null) {
t = new Trie();
put(key, t);
}
t.addToken(strings, begin + 1);
}
public List<String> tokenize(String data) {
String[] split = data.split("\\s+");
List<String> tokens = new ArrayList<String>();
int pos = 0;
while (pos < split.length) {
int tokenLength = getToken(split, pos, 0);
tokens.add(glue(split, pos, tokenLength));
pos += tokenLength;
}
return tokens;
}
public String glue(String[] parts, int pos, int length) {
StringBuilder sb = new StringBuilder();
sb.append(parts[pos]);
for (int i = pos + 1; i < pos + length; i++) {
sb.append(" ");
sb.append(parts[i]);
}
return sb.toString();
}
private int getToken(String[] tokens, int begin, int length) {
if (end) {
return length;
}
if (begin == tokens.length) {
return 1;
}
String key = tokens[begin];
Trie t = get(key);
if (t != null) {
return t.getToken(tokens, begin + 1, length + 1);
}
return 1;
}
}
and how to use it:
Trie t = new Trie();
t.addToken("AC Power");
t.addToken("date & time");
t.addToken("date & foo");
t.addToken("Speed & fun");
String data = "date & time AC Power Insolation Temperature Wind Speed";
List<String> tokens = t.tokenize(data);
for (String s : tokens) {
System.out.println(s);
}