Add negation operator support to expressions.

jcoleman · May 5, 2011 · 7f57ac9 · 7f57ac9
1 parent 97d9fd4
commit 7f57ac9
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Showing 3 changed files with 22 additions and 5 deletions.
diff --git a/features/arithmetic.feature b/features/arithmetic.feature
@@ -262,4 +262,15 @@ Feature: Arithmetic queries
     Then I should get the following results:
       | x    |
       | 1    |
-
+
+  Scenario: Negation (expression and value)
+    Given I have created the following "NumberDomain" instances:
+      | x    |
+      | -1   |
+      | 0    |
+      | 1    |
+    When I execute the code "NumberDomain.where { (- property('x')) gte: 0 }.all()"
+    Then I should get the following results:
+      | x    |
+      | -1   |
+      | 0    |
diff --git a/src/groovy/com/radiadesign/relationalscope/expression/ExpressionBase.groovy b/src/groovy/com/radiadesign/relationalscope/expression/ExpressionBase.groovy
@@ -54,4 +54,8 @@ class ExpressionBase {
     div(expr)
   }
 
+  ExpressionBase negative() {
+    return new ArithmeticExpression(null, this, '-', builder)
+  }
+
 }
diff --git a/src/java/com/radiadesign/hibernate/criterion/ArbitraryExpressionCriterion.java b/src/java/com/radiadesign/hibernate/criterion/ArbitraryExpressionCriterion.java
@@ -45,10 +45,12 @@ public String toSqlString(Criteria criteria, CriteriaQuery criteriaQuery)
   throws HibernateException {
     StringWriter sqlWriter = new StringWriter();
     sqlWriter.append('(');
-    if (rhs == null) { sqlWriter.append('('); }
-    appendSqlStringForExpression(lhs, sqlWriter, criteria, criteriaQuery);
-    if (rhs == null) { sqlWriter.append(')'); }
-    sqlWriter.append(' ');
+    if (lhs != null) {
+      if (rhs == null) { sqlWriter.append('('); }
+      appendSqlStringForExpression(lhs, sqlWriter, criteria, criteriaQuery);
+      if (rhs == null) { sqlWriter.append(')'); }
+      sqlWriter.append(' ');
+    }
     sqlWriter.append(operator);
     if (rhs != null) {
       sqlWriter.append(' ');