Recursive Nodes In XML Generated By JBPM 7

Question

The following XML is what JBPM spits out for variables used in a process. In other words, it is machine generated. I have tried for several hours to pa

Answer 1

If XML payload contains recursive structure you need to build similar Java POJO model classes. All values could extends the same interface or abstract class. Take a look on below example model:

@JsonTypeName("map-type")
class Root {

    @JacksonXmlProperty(localName = "entry")
    @JacksonXmlElementWrapper(localName = "entries")
    private List<Entry> entries;

    public List<Entry> getEntries() {
        return entries;
    }

    public void setEntries(List<Entry> entries) {
        this.entries = entries;
    }
}

@JsonTypeInfo(include = JsonTypeInfo.As.EXTERNAL_PROPERTY, property = "type", use = JsonTypeInfo.Id.NAME)
@JsonSubTypes({
        @JsonSubTypes.Type(name = "xs:string", value = StringType.class),
        @JsonSubTypes.Type(name = "jaxbMap", value = MapType.class)
})
interface JBPMValue {
}

class StringType implements JBPMValue {
    private String value;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    @JsonAnySetter
    public void anySetter(String key, String value) {
        this.value = value.trim();
    }

    @Override
    public String toString() {
        return value;
    }
}

class MapType implements JBPMValue {

    @JacksonXmlProperty(localName = "entry")
    @JacksonXmlElementWrapper(localName = "entries")
    private List<Entry> entries;

    public List<Entry> getEntries() {
        return entries;
    }

    public void setEntries(List<Entry> entries) {
        this.entries = entries;
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder("MapType{");
        sb.append(System.lineSeparator());
        entries.forEach(e -> sb.append(e.toString()).append(System.lineSeparator()));
        sb.append('}');
        return sb.toString();
    }
}

class Entry {
    private String key;
    private JBPMValue value;

    public String getKey() {
        return key;
    }

    public void setKey(String key) {
        this.key = key;
    }

    public JBPMValue getValue() {
        return value;
    }

    public void setValue(JBPMValue value) {
        this.value = value;
    }

    @Override
    public String toString() {
        return "{" + key + "=" + value + "}";
    }
}

As you can see I used @JsonTypeInfo and @JsonSubTypes to define POJO classes for each type in XML. @JacksonXmlProperty and @JacksonXmlElementWrapper annotation are used to represent wrapped collections.

Now, we can create simple example how to use it:

import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeName;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;

import java.io.File;
import java.util.List;

public class XmlMapperApp {

    public static void main(String... args) throws Exception {
        File xmlFile = new File("./resource/test.xml").getAbsoluteFile();

        XmlMapper mapper = XmlMapper.xmlBuilder().build();
        Root root = mapper.readValue(xmlFile, Root.class);
        root.getEntries().forEach(System.out::println);
    }
}

Above code for your XML payload prints:

{document=MapType{
{org.jbpm.document.service.impl.DocumentImpl=MapType{
{identifier=fc3a87c9-d22c-449b-b772-756fcc9a385d}
{size=1186}
{name=dmv-registration.txt}
{link=fc3a87c9-d22c-449b-b772-756fcc9a385d}
{attributes=null}
{lastModified=Mon Mar 09
                                        18:19:25 PDT 2020}
{content=null}
}}
{uploader_name=murthy}
{uploader_mail=gandikotam@gmail.com}
}}
{initiator=kieserver}