Add Maps.toProperties

[electrum]

It would be helpful to have a method to convert a Map<String, String> to Properties to use when interacting with APIs that require it. For example, the JDBC Driver.connect() method takes a Properties.

public static Properties toProperties(Map<String, String> map) {
  Properties properties = new Properties();
  for (Map.Entry<String, String> entry : map.entrySet()) {
    properties.setProperty(entry.getKey(), entry.getValue());
  }
  return properties;
}

[kluever]

So the opposite of Maps.fromProperties(Properties)?

[electrum]

@kluever yes, exactly

[kluever]

Someone pointed out that Properties extends HashTable, so you can just do:

Properties properties = new Properties();
properties.putAll(map);

...so we probably don't need a whole new API for this. However, we could add something to the javadocs of fromProperties()?

[electrum]

That call is flagged as a warning in IDEs and other tools, since calling underlying Hashtable methods can corrupt the Properties object. Also, having the method allows using it as part of an expression without needing two additional statements. I agree it is not strictly necessary, but that is true of many things in Guava.

[electrum]

Would you consider reopening this?

• avoid warnings about calling type-unsafe methods on Properties
• allow using the result as an expression

[kluever]

From the Properties javadocs (emphasis my own):

Because Properties inherits from Hashtable, the put and putAll methods can be applied to a Properties object. Their use is strongly discouraged as they allow the caller to insert entries whose keys or values are not Strings.

Hmm, thoughts?

[keerthikorivi]

Is this issue accepted?

[kluever]

It is not accepted yet. We'll need to have an API review of this proposal, which requires doing some research into the google codebase to find compelling use-cases.

[keerthikorivi]

Ok.

[ronshapiro]

Should this be a view (Maps.asProperties()) or just a conversion?

[electrum]

I'm asking for a simple conversion.