SpEL supports projection on any kind of Collection (SPR-7493)

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2010 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,21 +64,22 @@ public class Projection extends SpelNodeImpl {
 		// and value, and they can be referenced in the operation
 		// eg. {'a':'y','b':'n'}.!{value=='y'?key:null}" == ['a', null]
 		if (operand instanceof Map) {
-			Map<?, ?> mapdata = (Map<?, ?>) operand;
+			Map<?, ?> mapData = (Map<?, ?>) operand;
 			List<Object> result = new ArrayList<Object>();
-			for (Map.Entry entry : mapdata.entrySet()) {
+			for (Map.Entry entry : mapData.entrySet()) {
 				try {
 					state.pushActiveContextObject(new TypedValue(entry, TypeDescriptor.valueOf(Map.Entry.class)));
-					result.add(children[0].getValueInternal(state).getValue());
+					result.add(this.children[0].getValueInternal(state).getValue());
-				} finally {
+				}
+				finally {
 					state.popActiveContextObject();
 				}
 			}
 			return new TypedValue(result,TypeDescriptor.valueOf(List.class)); // TODO unable to build correct type descriptor
-		} else if (operand instanceof List || operandIsArray) {
+		}
-			List<Object> data = new ArrayList<Object>();
+		else if (operand instanceof Collection || operandIsArray) {
-			Collection<?> c = (operand instanceof List) ? (Collection<?>) operand : Arrays.asList(ObjectUtils.toObjectArray(operand));
+			Collection<?> data = (operand instanceof Collection ? (Collection<?>) operand :
-			data.addAll(c);
+					Arrays.asList(ObjectUtils.toObjectArray(operand)));
 			List<Object> result = new ArrayList<Object>();
 			int idx = 0;
 			Class<?> arrayElementType = null;
@@ -88,10 +89,11 @@ public class Projection extends SpelNodeImpl {
 					state.enterScope("index", idx);
 					Object value = children[0].getValueInternal(state).getValue();
 					if (value != null && operandIsArray) {
-						arrayElementType = this.determineCommonType(arrayElementType, value.getClass());
+						arrayElementType = determineCommonType(arrayElementType, value.getClass());
 					}
 					result.add(value);
-				} finally {
+				}
+				finally {
 					state.exitScope();
 					state.popActiveContextObject();
 				}
@@ -106,15 +108,20 @@ public class Projection extends SpelNodeImpl {
 				return new TypedValue(resultArray, op.getTypeDescriptor());
 			}
 			return new TypedValue(result, op.getTypeDescriptor());
-		} else {
-			if (operand==null) {
-				if (nullSafe) {
-					return TypedValue.NULL;
-				} else {					
-					throw new SpelEvaluationException(getStartPosition(),SpelMessage.PROJECTION_NOT_SUPPORTED_ON_TYPE, "null");
 		}
-			} else {
+		else {
-				throw new SpelEvaluationException(getStartPosition(),SpelMessage.PROJECTION_NOT_SUPPORTED_ON_TYPE, operand.getClass().getName());
+			if (operand==null) {
+				if (this.nullSafe) {
+					return TypedValue.NULL;
+				}
+				else {
+					throw new SpelEvaluationException(getStartPosition(),
+							SpelMessage.PROJECTION_NOT_SUPPORTED_ON_TYPE, "null");
+				}
+			}
+			else {
+				throw new SpelEvaluationException(getStartPosition(),
+						SpelMessage.PROJECTION_NOT_SUPPORTED_ON_TYPE, operand.getClass().getName());
 			}
 		}
 	}

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

@@ -16,15 +16,16 @@
 
 package org.springframework.expression.spel;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
 import java.util.ArrayList;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.TreeMap;
 
+import static org.junit.Assert.*;
 import org.junit.Test;
+
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.Expression;
 import org.springframework.expression.ExpressionParser;
@@ -35,8 +36,6 @@ import org.springframework.expression.spel.support.StandardEvaluationContext;
 /**
  * @author Mark Fisher
  * @author Sam Brannen
- * 
- * @since 3.0
  */
 public class SelectionAndProjectionTests {
 
@@ -73,6 +72,39 @@ public class SelectionAndProjectionTests {
 		assertEquals(4, value);
 	}
 
+	@Test
+	public void selectionWithSet() throws Exception {
+		Expression expression = new SpelExpressionParser().parseRaw("integers.?[#this<5]");
+		EvaluationContext context = new StandardEvaluationContext(new SetTestBean());
+		Object value = expression.getValue(context);
+		assertTrue(value instanceof List);
+		List list = (List) value;
+		assertEquals(5, list.size());
+		assertEquals(0, list.get(0));
+		assertEquals(1, list.get(1));
+		assertEquals(2, list.get(2));
+		assertEquals(3, list.get(3));
+		assertEquals(4, list.get(4));
+	}
+
+	@Test
+	public void selectFirstItemInSet() throws Exception {
+		Expression expression = new SpelExpressionParser().parseRaw("integers.^[#this<5]");
+		EvaluationContext context = new StandardEvaluationContext(new SetTestBean());
+		Object value = expression.getValue(context);
+		assertTrue(value instanceof Integer);
+		assertEquals(0, value);
+	}
+
+	@Test
+	public void selectLastItemInSet() throws Exception {
+		Expression expression = new SpelExpressionParser().parseRaw("integers.$[#this<5]");
+		EvaluationContext context = new StandardEvaluationContext(new SetTestBean());
+		Object value = expression.getValue(context);
+		assertTrue(value instanceof Integer);
+		assertEquals(4, value);
+	}
+
 	@Test
 	public void selectionWithArray() throws Exception {
 		Expression expression = new SpelExpressionParser().parseRaw("integers.?[#this<5]");
@@ -195,6 +227,20 @@ public class SelectionAndProjectionTests {
 		assertEquals(7, list.get(2));
 	}
 
+	@Test
+	public void projectionWithSet() throws Exception {
+		Expression expression = new SpelExpressionParser().parseRaw("#testList.![wrapper.value]");
+		EvaluationContext context = new StandardEvaluationContext();
+		context.setVariable("testList", IntegerTestBean.createSet());
+		Object value = expression.getValue(context);
+		assertTrue(value instanceof List);
+		List list = (List) value;
+		assertEquals(3, list.size());
+		assertEquals(5, list.get(0));
+		assertEquals(6, list.get(1));
+		assertEquals(7, list.get(2));
+	}
+
 	@Test
 	public void projectionWithArray() throws Exception {
 		Expression expression = new SpelExpressionParser().parseRaw("#testArray.![wrapper.value]");
@@ -244,6 +290,21 @@ public class SelectionAndProjectionTests {
 		}
 	}
 
+	static class SetTestBean {
+
+		private final Set<Integer> integers = new LinkedHashSet<Integer>();
+
+		SetTestBean() {
+			for (int i = 0; i < 10; i++) {
+				integers.add(i);
+			}
+		}
+
+		public Set<Integer> getIntegers() {
+			return integers;
+		}
+	}
+
 	static class ArrayTestBean {
 
 		private final int[] ints = new int[10];
@@ -286,6 +347,14 @@ public class SelectionAndProjectionTests {
 			return list;
 		}
 
+		static Set<IntegerTestBean> createSet() {
+			Set<IntegerTestBean> set = new LinkedHashSet<IntegerTestBean>();
+			for (int i = 0; i < 3; i++) {
+				set.add(new IntegerTestBean(i + 5));
+			}
+			return set;
+		}
+
 		static IntegerTestBean[] createArray() {
 			IntegerTestBean[] array = new IntegerTestBean[3];
 			for (int i = 0; i < 3; i++) {