@Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("{");
        if (getCsv() != null)
            sb.append("Csv: ").append(getCsv());
        if (getJson() != null)
            sb.append("Json: ").append(getJson());
        if (getCompressionType() != null)
            sb.append("CompressionType: ").append(getCompressionType());
        sb.append("}");
        return sb.toString();
    }
Specifies object's compression format. Valid values: NONE, GZIP. Default Value: NONE.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/model/InputSerialization.java