Question

Basically, I got a file containing details about people, each person separated by a new line, e.g
“

name Marioka address 97 Garderners Road birthday 12-11-1982 \n
name Ada Lovelace gender woman\n
name James address 65 Watcher Avenue

” and so on..

And, I would like to parse them to [Keyword : Value] pair array, such as

{[Name, Marioka], [Address, 97 Gardeners Road], [Birthday, 12-11-1982]},
{[Name, Ada Lovelace], [Gender, Woman]}, and so on....

and so on. The keywords will be a set of defined words, in above case: name, address, birthday, gender, etc…

What is the best way to do this?

This is how I did it, it works but was wondering whether there are better solutions.

    private Map<String, String> readRecord(String record) {
        Map<String, String> attributeValuePairs = new HashMap<String, String>();
        Scanner scanner = new Scanner(record);
        String attribute = "", value = ""; 

        /* 
         * 1. Scan each word. 
         * 2. Find an attribute keyword and store it at "attribute".
         * 3. Following words will be stored as "value" until the next keyword is found.
         * 4. Return value-attribute pairs as HashMap
         */

        while(scanner.hasNext()) {
            String word = scanner.next();
            if (this.isAttribute(word)) {
                if (value.trim() != "") {
                    attributeValuePairs.put(attribute.trim(), value.trim());
                    value = "";
                }
                attribute = word;
            } else {
                value += word + " ";
            }
        }
        if (value.trim() != "") attributeValuePairs.put(attribute, value);

        scanner.close();
        return attributeValuePairs;
    }

    private boolean isAttribute(String word) {
        String[] attributes = {"name", "patientId", 
            "birthday", "phone", "email", "medicalHistory", "address"};
        for (String attribute: attributes) {
            if (word.equalsIgnoreCase(attribute)) return true;
        }
        return false;
    }

Answer 1

To extract values from a string, use regular expressions. I expect you to know how to read each line from a file and how to build up an array with the results.

Still this is not a good solution, since it doesn’t work if any of the keywords are included in the name or address… But that’s what you asked for…

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Test {

    public static void main(String[] args) {

        Pattern p = Pattern.compile("name (.+) address (.+) birthday (.+)");

        String text = "name Marioka address 97 Garderners Road birthday 12-11-1982";

        Matcher m = p.matcher(text);

        if (m.matches()) {
            System.out.println(m.group(1) + "\n" + m.group(2) + "\n"
                    + m.group(3));
        } else {
            System.out.println("String does not match");
        }
    }
}