Add support for inverted booleans.

2 files changed, 20 insertions, 2 deletions

diff --git a/src/main/java/com/beust/jcommander/JCommander.java b/src/main/java/com/beust/jcommander/JCommander.java
index b0ba149..59073c6 100644
--- a/src/main/java/com/beust/jcommander/JCommander.java
+++ b/src/main/java/com/beust/jcommander/JCommander.java
@@ -668,7 +668,9 @@ public class JCommander {
                             // an arity of 1, in which case we need to read the next value
                             if ((fieldType == boolean.class || fieldType == Boolean.class)
                                     && pd.getParameter().arity() == -1) {
-                                pd.addValue("true");
+                                // Flip the value this boolean was initialized with
+                                Boolean value = (Boolean) pd.getParameterized().get(pd.getObject());
+                                pd.addValue(value ? "false" : "true");
                                 requiredFields.remove(pd.getParameterized());
                             } else {
                                 increment = processFixedArity(args, i, pd, validate, fieldType);
@@ -829,7 +831,9 @@ public class JCommander {
         if (arity == 0 &&
                 (Boolean.class.isAssignableFrom(fieldType)
                         || boolean.class.isAssignableFrom(fieldType))) {
-            pd.addValue("true");
+            // Flip the value this boolean was initialized with
+            Boolean value = (Boolean) pd.getParameterized().get(pd.getObject());
+            pd.addValue(value ? "false" : "true");
             requiredFields.remove(pd.getParameterized());
         } else if (arity == 0) {
             throw new ParameterException("Expected a value after parameter " + arg);
diff --git a/src/test/java/com/beust/jcommander/JCommanderTest.java b/src/test/java/com/beust/jcommander/JCommanderTest.java
index a93966e..a95ab30 100644
--- a/src/test/java/com/beust/jcommander/JCommanderTest.java
+++ b/src/test/java/com/beust/jcommander/JCommanderTest.java
@@ -1505,6 +1505,20 @@ public class JCommanderTest {
         Assert.assertEquals(generateOption.configFile.getName(), "foo.txt");
     }
 
+    @Test
+    public void invertedBoolean() {
+        class Args {
+            @Parameter(names = {"--f"})
+            private boolean f = true;
+        }
+        Args args = new Args();
+        JCommander.newBuilder()
+                .addObject(args)
+                .args(new String[] { "--f"})
+                .build();
+        Assert.assertEquals(args.f, false);
+    }
+
     @Test(enabled = false)
     public static void main(String[] args) {