polish

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

@@ -31,8 +31,8 @@ import org.springframework.binding.expression.ExpressionVariable;
 import org.springframework.binding.expression.ParserContext;
 import org.springframework.binding.expression.ParserException;
 import org.springframework.binding.expression.support.CompositeStringExpression;
+import org.springframework.binding.expression.support.LiteralExpression;
 import org.springframework.binding.expression.support.NullParserContext;
-import org.springframework.binding.expression.support.StaticExpression;
 import org.springframework.util.Assert;
 
 /**
@@ -209,7 +209,7 @@ public class OgnlExpressionParser implements ExpressionParser {
 			if (prefixIndex >= startIdx) {
 				// a inner expression was found - this is a composite
 				if (prefixIndex > startIdx) {
-					expressions.add(new StaticExpression(expressionString.substring(startIdx, prefixIndex)));
+					expressions.add(new LiteralExpression(expressionString.substring(startIdx, prefixIndex)));
 					startIdx = prefixIndex;
 				}
 				int nextPrefixIndex = expressionString.indexOf(getExpressionPrefix(), prefixIndex
@@ -241,11 +241,11 @@ public class OgnlExpressionParser implements ExpressionParser {
 						expressions.add(doParseExpression(expressionString, context));
 					} else {
 						// treat entire string as a literal
-						expressions.add(new StaticExpression(expressionString));
+						expressions.add(new LiteralExpression(expressionString));
 					}
 				} else {
 					// no more ${expressions} found in string, add rest as static text
-					expressions.add(new StaticExpression(expressionString.substring(startIdx)));
+					expressions.add(new LiteralExpression(expressionString.substring(startIdx)));
 				}
 				startIdx = expressionString.length();
 			}

spring-binding/src/main/java/org/springframework/binding/expression/support/CompositeStringExpression.java

@@ -17,6 +17,7 @@ package org.springframework.binding.expression.support;
 
 import org.springframework.binding.expression.EvaluationException;
 import org.springframework.binding.expression.Expression;
+import org.springframework.binding.expression.SetValueAttempt;
 import org.springframework.core.style.ToStringCreator;
 
 /**
@@ -49,7 +50,8 @@ public class CompositeStringExpression implements Expression {
 	}
 
 	public void setValue(Object context, Object value) throws EvaluationException {
-		throw new UnsupportedOperationException("Cannot set a composite string expression value");
+		throw new EvaluationException(new SetValueAttempt(this, context, value), new UnsupportedOperationException(
+				"Cannot set a composite string expression value"));
 	}
 
 	public String toString() {

spring-binding/src/main/java/org/springframework/binding/expression/support/LiteralExpression.java

@@ -0,0 +1,49 @@
+package org.springframework.binding.expression.support;
+
+import org.springframework.binding.expression.EvaluationException;
+import org.springframework.binding.expression.Expression;
+import org.springframework.binding.expression.SetValueAttempt;
+import org.springframework.util.Assert;
+
+public class LiteralExpression implements Expression {
+
+	/**
+	 * The string literal.
+	 */
+	private String literal;
+
+	/**
+	 * Create a literal expression for the given literal.
+	 * @param literal the literal
+	 */
+	public LiteralExpression(String literal) {
+		Assert.notNull(literal, "The literal is required");
+		this.literal = literal;
+	}
+
+	public int hashCode() {
+		return literal.hashCode();
+	}
+
+	public boolean equals(Object o) {
+		if (!(o instanceof LiteralExpression)) {
+			return false;
+		}
+		LiteralExpression other = (LiteralExpression) o;
+		return literal.equals(other.literal);
+	}
+
+	public Object getValue(Object context) throws EvaluationException {
+		return literal;
+	}
+
+	public void setValue(Object context, Object value) throws EvaluationException {
+		throw new EvaluationException(new SetValueAttempt(this, context, value), new UnsupportedOperationException(
+				"Cannot set a literal expression value.  Are you attempting to set a property expression?  "
+						+ "If so, should the expression string be enclosed in eval delimiters?"));
+	}
+
+	public String toString() {
+		return "literal('" + literal + "')";
+	}
+}