diff options
| -rw-r--r-- | src/library/scala/sys/BooleanProp.scala | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/src/library/scala/sys/BooleanProp.scala b/src/library/scala/sys/BooleanProp.scala index 74b0a9077b..e5e4668edb 100644 --- a/src/library/scala/sys/BooleanProp.scala +++ b/src/library/scala/sys/BooleanProp.scala @@ -63,12 +63,13 @@ object BooleanProp { def valueIsTrue[T](key: String): BooleanProp = new BooleanPropImpl(key, _.toLowerCase == "true") /** As an alternative, this method creates a BooleanProp which is true - * if the key exists in the map. This way -Dfoo.bar is enough to be - * considered true. + * if the key exists in the map and is not assigned a value other than "true", + * compared case-insensitively, or the empty string. This way -Dmy.property + * results in a true-valued property, but -Dmy.property=false does not. * * @return A BooleanProp with a liberal truth policy */ - def keyExists[T](key: String): BooleanProp = new BooleanPropImpl(key, _ => true) + def keyExists[T](key: String): BooleanProp = new BooleanPropImpl(key, s => s == "" || s.equalsIgnoreCase("true")) /** A constant true or false property which ignores all method calls. */ |