package net.sf.openrocket.util;
+import java.text.DecimalFormatSymbols;
+
+import net.sf.openrocket.logging.LogHelper;
+import net.sf.openrocket.startup.Application;
import de.congrace.exp4j.Calculable;
import de.congrace.exp4j.ExpressionBuilder;
-import de.congrace.exp4j.UnknownFunctionException;
-import de.congrace.exp4j.UnparsableExpressionException;
public class ExpressionParser {
+ private static final LogHelper log = Application.getLogger();
+ private static final char DECIMAL_SEPARATOR;
+ private static final char MINUS_SIGN;
+ static {
+ DecimalFormatSymbols symbols = DecimalFormatSymbols.getInstance();
+ DECIMAL_SEPARATOR = symbols.getDecimalSeparator();
+ MINUS_SIGN = symbols.getMinusSign();
+ }
public double parse(String expression) throws InvalidExpressionException {
+
+ String modified = null;
try {
- ExpressionBuilder builder = new ExpressionBuilder(modify(expression));
+ modified = modify(expression);
+ ExpressionBuilder builder = new ExpressionBuilder(modified);
Calculable calc = builder.build();
- return calc.calculate();
- } catch (java.lang.NumberFormatException e) {
- throw new InvalidExpressionException("Invalid expression: " + expression, e);
- } catch (UnknownFunctionException e) {
- throw new InvalidExpressionException("Invalid expression: " + expression, e);
- } catch (UnparsableExpressionException e) {
- throw new InvalidExpressionException("Invalid expression: " + expression, e);
- } catch (java.util.EmptyStackException e) {
+ double n = calc.calculate().getDoubleValue();
+ log.debug("Evaluated expression '" + expression + "' (modified='" + modified + "') to " + n);
+ return n;
+ } catch (Exception e) {
+ log.warn("Unable to parse expression '" + expression + "' (modified='" + modified + "')", e);
throw new InvalidExpressionException("Invalid expression: " + expression, e);
}
}
private String modify(String exp) throws InvalidExpressionException {
+
+ // Normalize digit equivalents, fraction sign, decimal separators and minus sign
char[] chars = exp.toCharArray();
- for( int i = 0; i< chars.length; i++ ) {
+ for (int i = 0; i < chars.length; i++) {
int value = Character.getNumericValue(chars[i]);
- if ( value >= 0 && value < 10 ) {
+ if (value >= 0 && value < 10) {
chars[i] = Character.toChars(48 + value)[0];
}
- if ( chars[i] == '\u2044') {
+ if (chars[i] == Chars.FRACTION) {
chars[i] = '/';
}
+ if (chars[i] == DECIMAL_SEPARATOR || chars[i] == ',') {
+ chars[i] = '.';
+ }
+ if (chars[i] == MINUS_SIGN) {
+ chars[i] = '-';
+ }
}
exp = String.copyValueOf(chars);
- exp = exp.replaceAll("(\\d+)\\s+(\\d+)\\s*/\\s*(\\d+)", "($1+$2/$3)");
- exp = exp.replace(',', '.');
+
+ // Replace fraction equivalents "1 3/4" with "(1+3/4)"
+ exp = exp.replaceAll("(?<![\\d.])(\\d+)\\s+(\\d+)\\s*/\\s*(\\d+)(?![\\d.])", "($1+$2/$3)");
+
// Disallow spaces between numbers - default is to remove spaces!
if (exp.matches(".*[0-9.]\\s+[0-9.].*")) {
- throw new InvalidExpressionException("Invalid expression: " + exp);
+ throw new InvalidExpressionException("Expression contains excess space: " + exp);
}
return exp;
}
-
}