SPR-5673: more intelligence in TemplateAwareExpressionParser. Supports prefix/suffix escaping and nesting of prefixes/suffixes

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@1000 50f2f4bb-b051-0410-bef5-90022cba6387

org.springframework.expression/src/main/java/org/springframework/expression/spel/ast/Selection.java

@@ -123,7 +123,7 @@ public class Selection extends SpelNodeImpl {
 				}
 			}
 			if ((variant == FIRST || variant == LAST) && result.size() == 0) {
-				return null;
+				return TypedValue.NULL_TYPED_VALUE;
 			}
 			if (variant == LAST) {
 				return new TypedValue(result.get(result.size() - 1),TypeDescriptor.valueOf(op.getTypeDescriptor().getElementType()));

org.springframework.expression/src/test/java/org/springframework/expression/spel/InProgressTests.java

@@ -352,6 +352,7 @@ public class InProgressTests extends ExpressionTestCase {
 	 
 	public void testSelection03() {
 		evaluate("mapOfNumbersUpToTen.?{key>5}.size()", "5", Integer.class);
+//		evaluate("listOfNumbersUpToTen.?{#this>5}", "5", ArrayList.class);
 	}
 
 	public void testSelection04() {
@@ -386,10 +387,4 @@ public class InProgressTests extends ExpressionTestCase {
 		assertFalse(expr.isWritable(new StandardEvaluationContext()));
 	}
 
-
-
-
-
-
-
 }

org.springframework.expression/src/test/java/org/springframework/expression/spel/SpringEL300Tests.java

@@ -16,6 +16,9 @@
 
 package org.springframework.expression.spel;
 
+import org.springframework.expression.Expression;
+import org.springframework.expression.spel.antlr.SpelAntlrExpressionParser;
+
 /**
  * Tests based on Jiras up to the release of Spring 3.0.0
  * 
@@ -26,5 +29,14 @@ public class SpringEL300Tests extends ExpressionTestCase {
 	public void testNPE_5661() {
 		evaluate("joinThreeStrings('a',null,'c')", "anullc", String.class);
 	}
+	
+	public void testNPE_5673() throws Exception {
+		SpelAntlrExpressionParser parser = new SpelAntlrExpressionParser();
+		Expression ex = parser.parseExpression("#{'Unable to render embedded object: File ({#this == 2\\}'}", TemplateExpressionParsingTests.HASH_DELIMITED_PARSER_CONTEXT);
+		assertEquals("Unable to render embedded object: File ({#this == 2}",ex.getValue());
+//		ex = parser.parseExpression("Unable to render embedded object: File (#{#this}) not found", TemplateExpressionParsingTests.HASH_DELIMITED_PARSER_CONTEXT);
+//		assertEquals()
+//		System.out.println(ex.getValue(new StandardEvaluationContext(new File("C:/temp"))));
+	}
 
 }

org.springframework.expression/src/test/java/org/springframework/expression/spel/TemplateExpressionParsingTests.java

@@ -41,6 +41,17 @@ public class TemplateExpressionParsingTests extends ExpressionTestCase {
 		}
 	};
 
+	public static final ParserContext HASH_DELIMITED_PARSER_CONTEXT = new ParserContext() {
+		public String getExpressionPrefix() {
+			return "#{";
+		}
+		public String getExpressionSuffix() {
+			return "}";
+		}
+		public boolean isTemplate() {
+			return true;
+		}
+	};
 
 	public void testParsingSimpleTemplateExpression01() throws Exception {
 		SpelAntlrExpressionParser parser = new SpelAntlrExpressionParser();
@@ -91,6 +102,52 @@ public class TemplateExpressionParsingTests extends ExpressionTestCase {
 		assertFalse(ex.isWritable(new StandardEvaluationContext()));
 	}
 	
+	public void testNestedExpressions() throws Exception {
+		SpelAntlrExpressionParser parser = new SpelAntlrExpressionParser();
+		// treat the nested ${..} as a part of the expression
+		Expression ex = parser.parseExpression("hello ${listOfNumbersUpToTen.${#this<5}} world",DEFAULT_TEMPLATE_PARSER_CONTEXT);
+		String s = ex.getValue(TestScenarioCreator.getTestEvaluationContext(),String.class);
+		assertEquals("hello 4 world",s);
+
+		// not a useful expression but tests nested expression syntax that clashes with template prefix/suffix
+		ex = parser.parseExpression("hello ${listOfNumbersUpToTen.${#root.listOfNumbersUpToTen.${#this%2==1}==3}} world",DEFAULT_TEMPLATE_PARSER_CONTEXT);
+		s = ex.getValue(TestScenarioCreator.getTestEvaluationContext(),String.class);
+		assertEquals("hello  world",s);
+
+		ex = parser.parseExpression("hello ${listOfNumbersUpToTen.${#this<5}} ${listOfNumbersUpToTen.${#this>5}} world",DEFAULT_TEMPLATE_PARSER_CONTEXT);
+		s = ex.getValue(TestScenarioCreator.getTestEvaluationContext(),String.class);
+		assertEquals("hello 4 10 world",s);
+		
+		try {
+			ex = parser.parseExpression("hello ${listOfNumbersUpToTen.${#this<5}} ${listOfNumbersUpToTen.${#this>5} world",DEFAULT_TEMPLATE_PARSER_CONTEXT);
+			fail("Should have failed");
+		} catch (ParseException pe) {
+			assertEquals("No ending suffix '}' for expression starting at character 41: ${listOfNumbersUpToTen.${#this>5} world",pe.getMessage());
+		}	
+		
+		try {
+			ex = parser.parseExpression("hello ${listOfNumbersUpToTen.${#root.listOfNumbersUpToTen.${#this%2==1==3}} world",DEFAULT_TEMPLATE_PARSER_CONTEXT);
+			fail("Should have failed");
+		} catch (ParseException pe) {
+			assertEquals("No ending suffix '}' for expression starting at character 6: ${listOfNumbersUpToTen.${#root.listOfNumbersUpToTen.${#this%2==1==3}} world",pe.getMessage());
+		}	
+	}
+	
+	public void testClashingWithSuffixes() throws Exception {
+		// Just wanting to use the prefix or suffix within the template:
+		Expression ex = parser.parseExpression("hello ${3+4} world",DEFAULT_TEMPLATE_PARSER_CONTEXT);
+		String s = ex.getValue(TestScenarioCreator.getTestEvaluationContext(),String.class);
+		assertEquals("hello 7 world",s);
+
+		ex = parser.parseExpression("hello ${3+4} wo\\${rld",DEFAULT_TEMPLATE_PARSER_CONTEXT);
+		s = ex.getValue(TestScenarioCreator.getTestEvaluationContext(),String.class);
+		assertEquals("hello 7 wo${rld",s);
+
+		ex = parser.parseExpression("hello ${3+4} wo\\}rld",DEFAULT_TEMPLATE_PARSER_CONTEXT);
+		s = ex.getValue(TestScenarioCreator.getTestEvaluationContext(),String.class);
+		assertEquals("hello 7 wo}rld",s);
+	}
+	
 	public void testParsingNormalExpressionThroughTemplateParser() throws Exception {
 		Expression expr = parser.parseExpression("1+2+3");
 		assertEquals(6,expr.getValue());
@@ -117,10 +174,12 @@ public class TemplateExpressionParsingTests extends ExpressionTestCase {
 			fail("Should have failed");
 		} catch (ParseException pe) {
 			assertEquals("No expression defined within delimiter '${}' at character 6",pe.getMessage());
-		}
-		
+		}		
 	}
 
+
+	// ---
+	
 	private void checkString(String expectedString, Object value) {
 		if (!(value instanceof String)) {
 			fail("Result was not a string, it was of type " + value.getClass() + "  (value=" + value + ")");
@@ -130,15 +189,4 @@ public class TemplateExpressionParsingTests extends ExpressionTestCase {
 		}
 	}
 
-	// TODO need to support this case but what is the neatest way? Escape the clashing delimiters in the expression
-	// string?
-	// public void testParsingTemplateExpressionThatEmbedsTheDelimiters() throws Exception {
-	// SpelExpressionParser parser = new SpelExpressionParser();
-	// Expression expr = parser.parseExpression("The quick ${{'green','brown'}.${true}} fox jumped over the ${'lazy'}
-	// dog",DefaultTemplateParserContext.INSTANCE);
-	// Object o = expr.getValue();
-	// System.out.println(o);
-	// assertEquals("The quick brown fox jumped over the lazy dog",o.toString());
-	// }
-
 }