Merge branch 'release-0.3.2'

1 files changed, 10 insertions, 2 deletions

diff --git a/src/main/java/sevenUnits/utils/ExpressionParser.java b/src/main/java/sevenUnits/utils/ExpressionParser.java
index 1d3d44d..941c2a4 100644
--- a/src/main/java/sevenUnits/utils/ExpressionParser.java
+++ b/src/main/java/sevenUnits/utils/ExpressionParser.java
@@ -461,10 +461,12 @@ public final class ExpressionParser<T> {
 	 * 
 	 * @param expression expression
 	 * @return expression in RPN
+	 * @throws IllegalArgumentException if expression is invalid (e.g.
+	 *                                  "{@code 3 *}")
 	 * @since 2019-03-17
 	 * @since v0.2.0
 	 */
-	private String convertExpressionToReversePolish(final String expression) {
+	String convertExpressionToReversePolish(final String expression) {
 		Objects.requireNonNull(expression, "expression must not be null.");
 		
 		final List<String> components = new ArrayList<>();
@@ -541,6 +543,9 @@ public final class ExpressionParser<T> {
 			switch (this
 					.getTokenType(components.get(highestPriorityOperatorPosition))) {
 			case UNARY_OPERATOR:
+				if (components.size() < 2)
+					throw new IllegalArgumentException(
+							"Invalid expression \"" + expression + "\"");
 				final String unaryOperator = components
 						.remove(highestPriorityOperatorPosition);
 				final String operand = components
@@ -549,6 +554,9 @@ public final class ExpressionParser<T> {
 						operand + " " + unaryOperator);
 				break;
 			case BINARY_OPERATOR:
+				if (components.size() < 3)
+					throw new IllegalArgumentException(
+							"Invalid expression \"" + expression + "\"");
 				final String binaryOperator = components
 						.remove(highestPriorityOperatorPosition);
 				final String operand1 = components
@@ -672,7 +680,7 @@ public final class ExpressionParser<T> {
 	 * @since 2019-03-14
 	 * @since v0.2.0
 	 */
-	private T parseReversePolishExpression(final String expression) {
+	T parseReversePolishExpression(final String expression) {
 		Objects.requireNonNull(expression, "expression must not be null.");
 		
 		final Deque<T> stack = new ArrayDeque<>();