Fixed null pointers when reading null properties in xml importer/exporter

astrid/plugin-src/com/todoroo/astrid/backup/TasksXmlExporter.java

@@ -218,10 +218,14 @@ public class TasksXmlExporter {
     private final XmlWritingPropertyVisitor xmlWritingVisitor = new XmlWritingPropertyVisitor();
 
     private class XmlWritingPropertyVisitor implements PropertyVisitor<Void, AbstractModel> {
+        private static final String NULL = "null"; //$NON-NLS-1$
+
         @Override
         public Void visitInteger(Property<Integer> property, AbstractModel data) {
             try {
-                xml.attribute(null, property.name, data.getValue(property).toString());
+                Integer value = data.getValue(property);
+                String valueString = (value == null) ? NULL : value.toString();
+                xml.attribute(null, property.name, valueString);
             } catch (UnsupportedOperationException e) {
                 // didn't read this value, do nothing
             } catch (IllegalArgumentException e) {
@@ -237,7 +241,9 @@ public class TasksXmlExporter {
         @Override
         public Void visitLong(Property<Long> property, AbstractModel data) {
             try {
-                xml.attribute(null, property.name, data.getValue(property).toString());
+                Long value = data.getValue(property);
+                String valueString = (value == null) ? NULL : value.toString();
+                xml.attribute(null, property.name, valueString);
             } catch (UnsupportedOperationException e) {
                 // didn't read this value, do nothing
             } catch (IllegalArgumentException e) {
@@ -253,7 +259,9 @@ public class TasksXmlExporter {
         @Override
         public Void visitDouble(Property<Double> property, AbstractModel data) {
             try {
-                xml.attribute(null, property.name, data.getValue(property).toString());
+                Double value = data.getValue(property);
+                String valueString = (value == null) ? NULL : value.toString();
+                xml.attribute(null, property.name, valueString);
             } catch (UnsupportedOperationException e) {
                 // didn't read this value, do nothing
             } catch (IllegalArgumentException e) {

astrid/plugin-src/com/todoroo/astrid/backup/TasksXmlImporter.java

@@ -296,12 +296,16 @@ public class TasksXmlImporter {
         private final XmlReadingPropertyVisitor xmlReadingVisitor = new XmlReadingPropertyVisitor();
 
         private class XmlReadingPropertyVisitor implements PropertyVisitor<Void, AbstractModel> {
+
+            private static final String NULL = "null";  //$NON-NLS-1$
+
             @Override
             public Void visitInteger(Property<Integer> property,
                     AbstractModel data) {
                 String value = xpp.getAttributeValue(null, property.name);
                 if(value != null)
-                    data.setValue(property, Integer.parseInt(value));
+                    data.setValue(property, NULL.equals(value) ?
+                            null : Integer.parseInt(value));
                 return null;
             }
 
@@ -309,7 +313,8 @@ public class TasksXmlImporter {
             public Void visitLong(Property<Long> property, AbstractModel data) {
                 String value = xpp.getAttributeValue(null, property.name);
                 if(value != null)
-                    data.setValue(property, Long.parseLong(value));
+                    data.setValue(property, NULL.equals(value) ?
+                            null : Long.parseLong(value));
                 return null;
             }
 
@@ -318,7 +323,8 @@ public class TasksXmlImporter {
                     AbstractModel data) {
                 String value = xpp.getAttributeValue(null, property.name);
                 if(value != null)
-                    data.setValue(property, Double.parseDouble(value));
+                    data.setValue(property, NULL.equals(value) ?
+                            null : Double.parseDouble(value));
                 return null;
             }