public String getPrefix() {
        return prefix;
    }
Gets the prefix parameter originally used to request this object listing, or
<code>null</code> if no prefix was specified.
All objects and common prefixes included
in this object listing start with the specified prefix.

@return The prefix parameter originally used to request this object
        listing. Returns <code>null</code> if no prefix was specified.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/model/ObjectListing.java