QuestionsPropertiesVisitor.java

package uva.sc.ql.evaluator;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Observable;

import uva.sc.ql.ast.IQLFormNodeVisitor;
import uva.sc.ql.ast.IQLStatementNodeVisitor;
import uva.sc.ql.atom.ID;
import uva.sc.ql.expression.Expression;
import uva.sc.ql.form.Form;
import uva.sc.ql.gui.helpers.QuestionData;
import uva.sc.ql.statements.IfStatement;
import uva.sc.ql.statements.Question;
import uva.sc.ql.statements.Statement;

/**
 * Visits the AST generating the values table - each change notifies the
 * listeners (observers) - that contains: 
 * 	for each question 
 * 		1. its expression for calculating the value and 
 * 		2. its expression for calculating if it is visible
 * 
 * @author Pantelis & Santiago
 */

@SuppressWarnings({ "rawtypes", "unchecked" })
public class QuestionsPropertiesVisitor extends Observable implements
	IQLStatementNodeVisitor, IQLFormNodeVisitor {

    private Map<ID, QuestionData> valuesTable = new HashMap<ID, QuestionData>();
    private Expression currentIfCondition;

    public QuestionData questionData(ID id) {
	return valuesTable.get(id);
    }

    public Map<ID, QuestionData> getValuesTable() {
	return valuesTable;
    }

    public void putToValuesTable(ID s, QuestionData d) {
	valuesTable.put(s, d);
	setChanged();
	notifyObservers();
    }

    public Expression visit(Form questionnaire) {
	List<Statement> statements = questionnaire.getStatements();
	for (Statement statement : statements) {
	    statement.accept(this);
	}
	return null;
    }

    public Expression visit(Question question) {
	if (question.getExpr() != null) {
	    putToValuesTable(question.getId(),
		    new QuestionData(question.getExpr(), currentIfCondition));
	} else {
	    putToValuesTable(question.getId(), new QuestionData(null,
		    currentIfCondition));
	}
	return null;
    }

    public Expression visit(IfStatement ifStatement) {
	currentIfCondition = ifStatement.getExpr();
	List<Question> questions = ifStatement.getQuestions();
	for (Question question : questions)
	    question.accept(this);
	currentIfCondition = null;
	return null;
    }
}