Kotlin 1.2.21 + SimpleXml 2.3.0 - consume List error (must mark set get method)

Question

I'm trying to consume XML using SimpleXML by Retrofit 2. After hours of struggling with Kotlin I decided to try Java version and the convert then to Kotlin. And Java version worked well...

error:

java.lang.RuntimeException: org.simpleframework.xml.core.MethodException: Annotation @org.simpleframework.xml.ElementList(data=false, empty=true, entry=, inline=true, name=entry, required=true, type=void) must mark a set or get method

I need a Kotlin model class that will be able to consume that XML. Here's input:

<feed>
   <entry>
        <id> someid </id>
        <published> somedate </published>
   </entry>

   <entry>
        <id> someid2 </id>
        <published> somedate2 </published>
   </entry>
</feed>

Java model class version (works fine):

@Root(name = "feed", strict = false)
public class MFeed {
    @ElementList(name = "entry", inline = true)
    private List<MEntry> entriesList;

    public MFeed(List<MEntry> entriesList) {
        this.entriesList = entriesList;
    }

    public MFeed() {
    }

    public List<MEntry> getEntriesList() {
        return entriesList;
    }

    public void setEntriesList(List<MEntry> entriesList) {
    this.entriesList = entriesList;
    }
}

@Root(name = "entry", strict = false)
public class MEntry {

    @Element(name = "id")
    private String id;

    @Element(name = "published")
    private String published;

    public MEntry() {
    }

    public MEntry(String id, String published) {
        this.id = id;
        this.published = published;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getPublished() {
        return published;
    }

    public void setPublished(String published) {
        this.published = published;
    }
}

and autogenerated Kotlin models look like this:

@Root(name = "feed", strict = false)
class Feed {
    @ElementList(name = "entry", inline = true)
    private var entriesList: List<MEntry>? = null

    //autogenerated by converter java -> kotlin
    constructor(entriesList: List<MEntry>) {
        this.entriesList = entriesList
    }

    //autogenerated by converter java -> kotlin
    constructor() {}
}

@Root(name = "entry", strict = false)
class Entry {
    @Element(name = "id")
    var id: String? = null

    @Element(name = "published")
    var published: String? = null

    //autogenerated by converter java -> kotlin
    constructor() {}

    //autogenerated by converter java -> kotlin
    constructor(id: String, published: String) {
        this.id = id
        this.published = published
    }
}

I've serfed a lot for consuming XML lists including this post, this and this. None worked. Perhaps they are obsolete. Anyone faced such problem?

Answer 1

Try to add @field to your annotation @Element*. And you may move properties to constructor and also you could add data modifier to your classes. Like this:

@Root(name = "feed", strict = false)
data class Feed(
        @field:ElementList(name = "entry", inline = true)
        var entriesList: List<Entry>? = null
)

@Root(name = "entry", strict = true)
data class Entry(
        @field:Element(name = "id")
        var id: String? = null,

        @field:Element(name = "published")
        var published: String? = null
)

With this I had successfully deserialise xml:

import org.simpleframework.xml.Element
import org.simpleframework.xml.ElementList
import org.simpleframework.xml.Root
import org.simpleframework.xml.core.Persister

private val testXml = """
<feed>
   <entry>
        <id> someid </id>
        <published> somedate </published>
   </entry>

   <entry>
        <id> someid2 </id>
        <published> somedate2 </published>
   </entry>
</feed>
""".trimIndent()

@Root(name = "feed", strict = false)
data class Feed(
        @field:ElementList(name = "entry", inline = true)
        var entriesList: List<Entry>? = null
)

@Root(name = "entry", strict = true)
data class Entry(
        @field:Element(name = "id")
        var id: String? = null,

        @field:Element(name = "published")
        var published: String? = null
)

fun main(args: Array<String>) {
    println(testXml)

    val serializer = Persister()

    val example = serializer.read(Feed::class.java, testXml)

    println(example)
}