src/main/java/com/arpnetworking/steno/Logger.java
static @Nullable String[] createKeysFromCollection(
            @Nullable final Collection<String> collection,
            @Nullable final String... keys) {
        if (isNullOrEmpty(keys)) {
            return collection == null ? null : collection.toArray(new String[collection.size()]);
        }
        if (isNullOrEmpty(collection)) {
            return keys;
        }
        final String[] combined = new String[collection.size() + keys.length];
        for (int i = 0; i < keys.length; ++i) {
            combined[i] = keys[i];
        }
        int i = 0;
        for (final String item : collection) {
            combined[keys.length + i++] = item;
        }
        return combined;
    }
static @Nullable String[] createKeysFromCollection(
            @Nullable final Collection<String> collection,
            @Nullable final String... keys) {
        if (isNullOrEmpty(keys)) {
            return collection == null ? null : collection.toArray(new String[collection.size()]);
        }
        if (isNullOrEmpty(collection)) {
            return keys;
        }
        final String[] combined = new String[collection.size() + keys.length];
        for (int i = 0; i < keys.length; ++i) {
            combined[i] = keys[i];
        }
        int i = 0;
        for (final String item : collection) {
            combined[keys.length + i++] = item;
        }
        return combined;
    }
static @ Nullable String [ ] createKeysFromCollection ( @ Nullable final Collection < String > collection , @ Nullable final String ... keys ) { if ( isNullOrEmpty ( keys ) ) { return collection == null ? null : collection . toArray ( new String [ collection . size ( ) ] ) ; } if ( isNullOrEmpty ( collection ) ) { return keys ; } final String [ ] combined = new String [ collection . size ( ) + keys . length ] ; for ( int i = 0 ; i < keys . length ; ++ i ) { combined [ i ] = keys [ i ] ; } int i = 0 ; for ( final String item : collection ) { combined [ keys . length + i ++ ] = item ; } return combined ; }
/* package private
/ * package private