polish

spring-binding/src/main/java/org/springframework/binding/expression/ognl/OgnlExpressionParser.java

@@ -133,6 +133,9 @@ public class OgnlExpressionParser implements ExpressionParser {
 
 	public Expression parseExpression(String expressionString, ParserContext context) throws ParserException {
 		Assert.notNull(expressionString, "The expression string to parse is required");
+		if (expressionString.length() == 0) {
+			return parseEmptyExpressionString(context);
+		}
 		Expression[] expressions = parseExpressions(expressionString, context);
 		if (expressions.length == 1) {
 			return expressions[0];
@@ -192,6 +195,19 @@ public class OgnlExpressionParser implements ExpressionParser {
 
 	// helper methods
 
+	/**
+	 * Helper that handles a empty expression string.
+	 */
+	private Expression parseEmptyExpressionString(ParserContext context) {
+		if (allowUndelimitedEvalExpressions) {
+			// let the parser handle it
+			return doParseExpression("", context);
+		} else {
+			// return a literal expression containing the empty string
+			return new LiteralExpression("");
+		}
+	}
+
 	/**
 	 * Helper that parses given expression string using the configured parser. The expression string can contain any
 	 * number of expressions all contained in "${...}" markers. For instance: "foo${expr0}bar${expr1}". The static

spring-binding/src/test/java/org/springframework/binding/expression/el/ELExpressionParserTests.java

@@ -40,6 +40,12 @@ public class ELExpressionParserTests extends TestCase {
 		}
 	}
 
+	public void testParseEmptyExpressionString() {
+		String expressionString = "";
+		Expression exp = parser.parseExpression(expressionString, null);
+		assertEquals("", exp.getValue(null));
+	}
+
 	public void testParseSimpleEvalExpressionNoEvalContextWithTypeCoersion() {
 		String expressionString = "#{3 + 4}";
 		Expression exp = parser.parseExpression(expressionString, new ParserContextImpl().expect(Integer.class));