Add support for add-list-attribute to render expressions

.gitattributes

@@ -0,0 +1,30 @@
+# Handle line endings automatically for files detected as text
+# and leave all files detected as binary untouched.
+* text=auto
+
+#
+# The above will handle all files NOT found below
+#
+# These files are text and should be normalized (Convert crlf => lf)
+*.css           text
+*.df            text
+*.java          text
+*.js            text
+*.json          text
+*.jsp           text
+*.properties    text
+*.sql           text
+*.svg           text
+*.tld           text
+*.txt           text
+*.xml           text
+
+# These files are binary and should be left untouched
+# (binary is a macro for -text -diff)
+*.dll           binary
+*.gif           binary
+*.ico           binary
+*.jar           binary
+*.png           binary
+*.so            binary
+

.gitignore

@@ -0,0 +1,25 @@
+/target/
+/tiles-api/target/
+/tiles-core/target/
+/tiles-template/target/
+/tiles-servlet/target/
+/tiles-jsp/target/
+/tiles-freemarker/target/
+/tiles-velocity/target/
+/tiles-el/target/
+/tiles-ognl/target/
+/tiles-mvel/target/
+/tiles-compat/target/
+/tiles-extras/target/
+/tiles-test-pom/tiles-test-db/target/
+/tiles-test-pom/tiles-test-alt/target/
+/tiles-test-pom/target/
+/tiles-test-pom/tiles-test-common/target/
+/tiles-test-pom/tiles-test/target/
+/assembly/target/
+*~
+*.bak
+*.swp
+*.log
+.DS_Store
+pom.xml.versionsBackup

tiles-api/src/main/java/org/apache/tiles/Attribute.java

@@ -289,7 +289,7 @@ public String toString() {
         if (value != null) {
             return value.toString();
         }
-        return null;
+        return "null";
     }
 
     /**

tiles-api/src/test/java/org/apache/tiles/AttributeTest.java

@@ -203,7 +203,7 @@ public void testToString() {
         roles.add("role2");
         assertEquals("my.value", attribute.toString());
         attribute.setValue(null);
-        assertNull(attribute.toString());
+        assertEquals(attribute.toString(), "null");
     }
 
     /**

tiles-core/src/main/java/org/apache/tiles/evaluator/AbstractAttributeEvaluator.java

@@ -18,11 +18,18 @@
  * specific language governing permissions and limitations
  * under the License.
  */
+
 package org.apache.tiles.evaluator;
 
+import java.util.ArrayList;
+import java.util.List;
 import org.apache.tiles.Attribute;
 import org.apache.tiles.Expression;
+import org.apache.tiles.ListAttribute;
 import org.apache.tiles.request.Request;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 
 /**
  * Abstract class to link a correct evaluation of an attribute, by evaluating
@@ -33,7 +40,10 @@
  */
 public abstract class AbstractAttributeEvaluator implements AttributeEvaluator {
 
+    private static final Logger log = LoggerFactory.getLogger(AbstractAttributeEvaluator.class);
+
     /** {@inheritDoc} */
+    @Override
     public Object evaluate(Attribute attribute, Request request) {
         if (attribute == null) {
             throw new IllegalArgumentException("The attribute cannot be null");
@@ -44,11 +54,49 @@ public Object evaluate(Attribute attribute, Request request) {
         if (retValue == null) {
             Expression expression = attribute.getExpressionObject();
             if (expression != null) {
+                log.debug("Evaluating expression: [attribute={},expression={}]", attribute, expression);
                 retValue = evaluate(attribute.getExpressionObject()
                         .getExpression(), request);
             }
+        } else if (retValue instanceof List) {
+            log.debug("Evaluating list for expressions: {}", retValue);
+            retValue = evaluateList((List) retValue, request);
         }
 
+        log.debug("Returning result: {}", retValue);
         return retValue;
     }
+
+    private List evaluateList(List src, Request request) {
+        List res = new ArrayList();
+        for (Object val : src) {
+            if (val instanceof ListAttribute) {
+                log.debug("Evaluating list entry (ListAttribute): {}", val);
+                res.add(evaluateList(((ListAttribute) val).getValue(), request));
+            } else if (val instanceof Attribute) {
+                log.debug("Evaluating list entry (Attribute): {}", val);
+                Attribute att = (Attribute) val;
+                if (att.getValue() != null) {
+                    res.add(att.getValue() instanceof List
+                            ? evaluateList((List) att.getValue(), request)
+                            : att);
+                } else {
+                    Expression expression = att.getExpressionObject();
+                    if (expression != null) {
+                        log.debug("Evaluating list entry expression: {}", expression);
+                        att = att.clone();
+                        att.setValue(evaluate(expression.getExpression(), request));
+                        res.add(att);
+                    } else {
+                        res.add(att);
+                    }
+                }
+            } else {
+                log.debug("Evaluating list entry ({}): {}", val.getClass(), val);
+                res.add(val);
+            }
+        }
+        return res;
+    }
+
 }