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README: recommend hasPath rather than catching Missing

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Havoc Pennington 2014-10-13 05:49:46 -04:00
parent 0a7db6a126
commit 5038949cff
1 changed files with 9 additions and 7 deletions
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12
README.md
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@ -306,10 +306,13 @@ options:
1. Set it in a `reference.conf` included in your library or
application jar, so there's a default value.
2. Catch and handle `ConfigException.Missing`.
3. Use the `Config.hasPath()` method to check in advance whether
2. Use the `Config.hasPath()` method to check in advance whether
the path exists (rather than checking for `null`/`None` after as
you might in other APIs).
3. Catch and handle `ConfigException.Missing`. NOTE: using an
exception for control flow like this is much slower than using
`Config.hasPath()`; the JVM has to do a lot of work to throw
an exception.
4. In your initialization code, generate a `Config` with your
defaults in it (using something like `ConfigFactory.parseMap()`)
then fold that default config into your loaded config using
@ -341,10 +344,9 @@ like this to use the idiomatic `Option` syntax:
```scala
implicit class RichConfig(val underlying: Config) extends AnyVal {
def getOptionalBoolean(path: String): Option[Boolean] = try {
def getOptionalBoolean(path: String): Option[Boolean] = if (underlying.hasPath(path)) {
Some(underlying.getBoolean(path))
} catch {
case e: ConfigException.Missing =>
} else {
None
}
}