public void setPrefix(String prefix) {
        this.prefix = prefix;
    }
Sets the optional prefix parameter, restricting the response to keys that
begin with the specified prefix.

@param prefix
           The optional prefix parameter, restricting the response to keys
           that begin with the specified prefix.

@see ListObjectsRequest#getPrefix()
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/model/ListObjectsRequest.java