@Override
    public double getDouble(@NonNull String key) {
        if (key == null) { throw new IllegalArgumentException("key cannot be null."); }

        synchronized (lock) {
            return CBLConverter.asDouble(getMValue(internalDict, key), internalDict);
        }
    }
@ Override public double getDouble ( @ NonNull String key ) { if ( key == null ) { throw new IllegalArgumentException ( "key cannot be null." ) ; } synchronized ( lock ) { return CBLConverter . asDouble ( getMValue ( internalDict , key ) , internalDict ) ; } }
Gets a property's value as an double.
Integers will be converted to double. The value `true` is returned as 1.0, `false` as 0.0.
Returns 0.0 if the property doesn't exist or does not have a numeric value.

@param key the key
@return the double value.