/**
 * A class that parses input strings of the form:
 * <Last name>,<First name>|<ID #>
 * Where all spaces are ignored.
 * This parser assumes that there are no ',' or '|' characters
 * in the last name, first name, or ID #.
 * @author bederson
 */
public class Parser {
	// These hold the data as they are parsed
	private String lastName, firstName, studentId;
	// These are true when the relavant word has been parsed
	private boolean firstNameComplete, lastNameComplete;
	private char charValue;  // The current character being analyzed

	/**
	 * Resets the state of the parser to the initial state.
	 * This is an internal method and is used internally in support
	 * of the parsers.
	 */
	private void reset() {
		firstNameComplete = false;
		lastNameComplete = false;
		lastName = "";
		firstName = "";
		studentId = "";
	}

	/**
	 * Parse the input string.  When it is complete, the class
	 * instance variables holding first name, last name and ID # will
	 * be set, and can be accessed through the appropriate getter methods.
	 * @see getFirstName()
	 * @see getLastName()
	 * @see getStudentID()
	 * @param data The input string to parse
	 */
	void parseInputOne(String data) {
		// This version is implemented with a sequence of if/else statements
		
		reset();  // Crucial to reset parser before start, or there will
		          // be problems if a second string is parsed
		
		for (int i=0; i<data.length(); i++) {
			charValue = data.charAt(i);

			if (charValue == ',') {         // ',' uniquely ends last name
				lastNameComplete = true;
			} else if (charValue == '|') {  // '|' uniquely ends first name
				firstNameComplete = true;
			} else if (charValue == ' ') {  // We throw away all spaces
				// ignore
			} else {                // Anything else should be added to the current word
				if (!lastNameComplete) {
					lastName += charValue;
				} else {
					if (!firstNameComplete) {
						firstName += charValue;
					} else {
						studentId += charValue;
					}
				}
			}
		}
	}

	/**
	 * Parse the input string.  When it is complete, the class
	 * instance variables holding first name, last name and ID # will
	 * be set, and can be accessed through the appropriate getter methods.
	 * @see getFirstName()
	 * @see getLastName()
	 * @see getStudentID()
	 * @param data The input string to parse
	 */
	void parseInputTwo(String data) {
		// This version is implemented with a switch statement
		
		reset();  // Crucial to reset parser before start, or there will
		          // be problems if a second string is parsed
		
		for (int i=0; i<data.length(); i++) {
			charValue = data.charAt(i);
			switch (charValue) {
				case ',' :    // ',' uniquely ends last name
					lastNameComplete = true;
					break;
				case '|' :    // '|' uniquely ends last name
					firstNameComplete = true;
					break;
				case ' ' :    // We throw away all spaces
					// ignore
					break;
				default :     // Anything else should be added to the current word
					if (!lastNameComplete) {
						lastName += charValue;
					} else {
						if (!firstNameComplete) {
							firstName += charValue;
						} else {
							studentId += charValue;
						}
					}
					break;
			}
		}
	}

	String getFirstName() {
		return firstName;
	}

	String getLastName() {
		return lastName;
	}

	String getStudentId() {
		return studentId;
	}

	/**
	 * Simple testing program trys out both parsers
	 * @param args Ignored
	 */
	public static void main(String[] args) {
		Parser parser = new Parser();
		String data = new String(" Smith,John | 123-45-6789");

		parser.parseInputOne(data);
		System.out.println(parser.getFirstName() + " " + parser.getLastName());
		System.out.println(parser.getStudentId());
		System.out.println();

		System.out.println("Using parseInputTwo");
		parser.parseInputTwo(data);
		System.out.println(parser.getFirstName() + " " + parser.getLastName());
		System.out.println(parser.getStudentId());
	}
}