Marc4J计算数据的记录长度和基址

Question

我正在使用Unimarc，使用marc4j库。在我的系统中，我已经能够获得org.marc4j.marc.Record的一个实例。现在，我很难弄清楚如何计算数据的记录长度和基地址。在唱片领队中使用。

我一直试图找出如何使用marc4j库或外部库来完成这个任务，但到目前为止还没有找到。

我怎样才能得到这两条信息？

Answer 1

我在文档中找不到任何东西，但我设法做到了。职能如下：

public String getISO2709 (org.marc4j.marc.Record record ){
    OutputStream output = new OutputStream() {
        private StringBuilder string = new StringBuilder();

        @Override
        public void write(int b) throws IOException {
            this.string.append((char) b );
        }

        public String toString() {
            return this.string.toString();
        }
    };
    MarcStreamWriter writer = new MarcStreamWriter(output);
    writer.write(record);
    return output.toString();
}


public String getNoticeLength(org.marc4j.marc.Record record, org.marc4j.marc.Leader currentLeader){

    int recordLength = this.getISO2709(record).length();

    String ret = StringUtils.padLeft(String.valueOf(recordLength), '0', 5);
    if(ret.length() > 5) ret ="00000"; // since the header has space for only 5 chars, this 00000 will indicate the length was invalid

    return ret;
}

public  String getBaseAddressOfData(org.marc4j.marc.Record record, org.marc4j.marc.Leader currentLeader){

    String iso2709 = this.getISO2709(record);
    StringBuilder sb = new StringBuilder();

    for (ControlField cf : record.getControlFields()) {
        sb.append(cf.getData() + "\u001E"); // this is the character that separates the values for the control fields iso2709
    }

    int index = iso2709.indexOf(sb.toString());

    String ret = StringUtils.padLeft(String.valueOf(index), '0', 5);
    if(ret.length() > 5) ret="00000";

    return ret;
}