protected void add(final String name, final String[] newValues) {
        String[] values = metadata.get(name);
        if (values == null) {
            set(name, newValues);
        } else {
            for (String val : newValues) {
                add(name, val);
            }
        }
    }
Add a metadata name/value mapping. Add the specified value to the list of
values associated to the specified metadata name.

@param name  the metadata name.
@param newValues the metadata values
tika-core/src/main/java/org/apache/tika/metadata/Metadata.java