If we have a setter but no getter, try to find a field to calculate the default value.

2 files changed, 32 insertions, 2 deletions

diff --git a/src/main/java/com/beust/jcommander/Parameterized.java b/src/main/java/com/beust/jcommander/Parameterized.java
index 14ce975..ff8753b 100644
--- a/src/main/java/com/beust/jcommander/Parameterized.java
+++ b/src/main/java/com/beust/jcommander/Parameterized.java
@@ -117,7 +117,22 @@ public class Parameterized {
     } catch (SecurityException e) {
       throw new ParameterException(e);
     } catch (NoSuchMethodException e) {
-      return null;
+      // Try to find a field
+      String name = m_method.getName();
+      String fieldName = Character.toLowerCase(name.charAt(3)) + name.substring(4);
+      Object result = null;
+      try {
+        Field field = m_method.getDeclaringClass().getDeclaredField(fieldName);
+        if (field != null) {
+          field.setAccessible(true);
+          result = field.get(object);
+        }
+      } catch(NoSuchFieldException ex) {
+        // ignore
+      } catch(IllegalAccessException ex) {
+        // ignore
+      }
+      return result;
     } catch (IllegalArgumentException e) {
       throw new ParameterException(e);
     } catch (IllegalAccessException e) {
diff --git a/src/test/java/com/beust/jcommander/MethodSetterTest.java b/src/test/java/com/beust/jcommander/MethodSetterTest.java
index 8f6320b..f995ad6 100644
--- a/src/test/java/com/beust/jcommander/MethodSetterTest.java
+++ b/src/test/java/com/beust/jcommander/MethodSetterTest.java
@@ -78,8 +78,23 @@ public class MethodSetterTest {
     Assert.assertEquals(arg.port, new Integer(42));
   }
 
+  public void noGetterButWithField() {
+    class Arg {
+      private Integer port = 43;
+
+      @Parameter(names = "--port")
+      public void setPort(String port) {
+        this.port = Integer.parseInt(port);
+      }
+    }
+    Arg arg = new Arg();
+    JCommander jc = new JCommander(arg, new String[] { "--port", "42" });
+    ParameterDescription pd = jc.getParameters().get(0);
+    Assert.assertEquals(pd.getDefault(), 43);
+  }
+
   @Test(enabled = false)
   public static void main(String[] args) throws Exception {
-    new MethodSetterTest().getterReturningNonString();
+    new MethodSetterTest().noGetterButWithField();
   }
 }