polish

spring-binding/src/main/java/org/springframework/binding/expression/Expression.java

@@ -44,7 +44,8 @@ public interface Expression {
 	 * Returns the most general type that can be passed to the {@link #setValue(Object, Object)} method for the given
 	 * context.
 	 * @param context the context to evaluate
-	 * @return the most general type of value that can be set on this context
+	 * @return the most general type of value that can be set on this context, or <code>null</code> if the type
+	 * information cannot be determined
 	 * @throws EvaluationException an exception occurred during expression evaluation
 	 */
 	public Class getValueType(Object context) throws EvaluationException;

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

@@ -131,6 +131,13 @@ public class ELExpressionParserTests extends TestCase {
 		assertEquals("foo2bar", exp.getValue(target));
 	}
 
+	public void testGetValueTypeNullCollectionValue() {
+		String exp = "list[3]";
+		Expression e = parser.parseExpression(exp, null);
+		TestBean target = new TestBean();
+		assertEquals(null, e.getValueType(target));
+	}
+
 	public static class TestBean {
 		private String value = "foo";
 
@@ -153,6 +160,7 @@ public class ELExpressionParserTests extends TestCase {
 			list.add("1");
 			list.add("2");
 			list.add("3");
+			list.add(null);
 		}
 
 		public TestBean getBean() {
@@ -178,6 +186,10 @@ public class ELExpressionParserTests extends TestCase {
 		public void setMaximum(int maximum) {
 			this.maximum = maximum;
 		}
+
+		public List getList() {
+			return list;
+		}
 	}
 
 	private static class TestELContextFactory implements ELContextFactory {

spring-binding/src/test/java/org/springframework/binding/expression/ognl/OgnlExpressionParserTests.java

@@ -160,4 +160,10 @@ public class OgnlExpressionParserTests extends TestCase {
 		Expression e = parser.parseExpression(exp, null);
 		assertEquals(boolean.class, e.getValueType(bean));
 	}
+
+	public void testGetValueTypeNullCollectionValue() {
+		String exp = "list[0]";
+		Expression e = parser.parseExpression(exp, null);
+		assertEquals(null, e.getValueType(bean));
+	}
 }

spring-webflow/src/main/java/org/springframework/webflow/expression/DefaultExpressionParserFactory.java

@@ -20,10 +20,7 @@ import javax.el.ExpressionFactory;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.binding.convert.ConversionService;
-import org.springframework.binding.expression.Expression;
 import org.springframework.binding.expression.ExpressionParser;
-import org.springframework.binding.expression.ParserContext;
-import org.springframework.binding.expression.ParserException;
 import org.springframework.binding.expression.el.DefaultExpressionFactoryUtils;
 import org.springframework.util.ClassUtils;
 import org.springframework.webflow.expression.el.WebFlowELExpressionParser;
@@ -61,14 +58,7 @@ public final class DefaultExpressionParserFactory {
 	 * @return the expression parser
 	 */
 	public static synchronized ExpressionParser getExpressionParser() {
-		// return a wrapper that will lazily load the default expression parser
-		// this prevents the underlying parser from being initialized until it is actually used
-		// this allows the EL to be an optional dependency if the expression parser wrapper is replaced and never used
-		return new ExpressionParser() {
-			public Expression parseExpression(String expressionString, ParserContext context) throws ParserException {
-				return getDefaultExpressionParser().parseExpression(expressionString, context);
-			}
-		};
+		return getDefaultExpressionParser();
 	}
 
 	/**
@@ -78,7 +68,7 @@ public final class DefaultExpressionParserFactory {
 	 * @return the expression parser
 	 */
 	public static synchronized ExpressionParser getExpressionParser(final ConversionService conversionService) {
-		return new DefaultExpressionParserProxy(conversionService);
+		return createDefaultExpressionParser(conversionService);
 	}
 
 	/**
@@ -129,23 +119,4 @@ public final class DefaultExpressionParserFactory {
 			}
 		}
 	}
-
-	private static class DefaultExpressionParserProxy implements ExpressionParser {
-		private ConversionService conversionService;
-
-		private ExpressionParser instance;
-
-		public DefaultExpressionParserProxy(ConversionService conversionService) {
-			this.conversionService = conversionService;
-		}
-
-		public Expression parseExpression(String expressionString, ParserContext context) throws ParserException {
-			synchronized (instance) {
-				if (instance == null) {
-					instance = createDefaultExpressionParser(conversionService);
-				}
-			}
-			return instance.parseExpression(expressionString, context);
-		}
-	}
 }

spring-webflow/src/main/java/org/springframework/webflow/mvc/view/AbstractMvcView.java

@@ -57,7 +57,6 @@ import org.springframework.webflow.execution.Event;
 import org.springframework.webflow.execution.FlowExecutionKey;
 import org.springframework.webflow.execution.RequestContext;
 import org.springframework.webflow.execution.View;
-import org.springframework.webflow.expression.DefaultExpressionParserFactory;
 
 /**
  * Base view implementation for the Spring Web MVC Servlet and Spring Web MVC Portlet frameworks.
@@ -76,7 +75,7 @@ public abstract class AbstractMvcView implements View {
 
 	private RequestContext requestContext;
 
-	private ExpressionParser expressionParser = DefaultExpressionParserFactory.getExpressionParser();
+	private ExpressionParser expressionParser;
 
 	private ConversionService conversionService;
 

spring-webflow/src/test/java/org/springframework/webflow/TestBean.java

@@ -16,6 +16,7 @@
 package org.springframework.webflow;
 
 import java.io.Serializable;
+import java.util.Date;
 
 /**
  * Simple test bean used by some test cases. Note that this bean has value semantics.
@@ -26,6 +27,8 @@ public class TestBean implements Serializable {
 
 	public int datum2;
 
+	private Date datum3;
+
 	public boolean executed;
 
 	public void execute() {
@@ -40,6 +43,14 @@ public class TestBean implements Serializable {
 		return datum2;
 	}
 
+	public Date getDatum3() {
+		return datum3;
+	}
+
+	public void setDatum3(Date datum3) {
+		this.datum3 = datum3;
+	}
+
 	public boolean isExecuted() {
 		return executed;
 	}

spring-webflow/src/test/java/org/springframework/webflow/expression/DefaultExpressionParserFactoryTests.java

@@ -15,9 +15,15 @@
  */
 package org.springframework.webflow.expression;
 
+import java.util.Calendar;
+
 import junit.framework.TestCase;
 
+import org.springframework.binding.convert.service.DefaultConversionService;
+import org.springframework.binding.expression.Expression;
 import org.springframework.binding.expression.ExpressionParser;
+import org.springframework.binding.expression.support.FluentParserContext;
+import org.springframework.webflow.TestBean;
 
 /**
  * Unit tests for {@link DefaultExpressionParserFactory}.
@@ -28,4 +34,16 @@ public class DefaultExpressionParserFactoryTests extends TestCase {
 		ExpressionParser parser = DefaultExpressionParserFactory.getExpressionParser();
 		assertNotNull(parser);
 	}
+
+	public void testGetDefaultExpressionParserConversionService() {
+		DefaultConversionService conversionService = new DefaultConversionService();
+		ExpressionParser parser = DefaultExpressionParserFactory.getExpressionParser(conversionService);
+		Expression exp = parser.parseExpression("datum3", new FluentParserContext().expectResult(String.class));
+		TestBean context = new TestBean();
+		Calendar cal = Calendar.getInstance();
+		cal.set(2008, 1, 1);
+		exp.setValue(context, cal.getTime());
+		String string = (String) exp.getValue(context);
+		assertEquals(null, string);
+	}
 }