LookupField with one-to-many relationship

I want to show in my document a one-to-many relationship- a simple drop-down list with values. For that, I trying to create and configure LookupField component by using Cuba platform.

I have two entities:

CardItem:

@NamePattern("The document in the following state: %s|cardState")
@Table(name = "TKB_CARD_ITEM")
@Entity(name = "tkb$CardItem")
public class CardItem extends StandardEntity {

    // skipped

CardType:

@NamePattern("CardType: %s, %s |cardTypeItem, cardTypeName")
@Table(name = "TKB_CARD_TYPE")
@Entity(name = "tkb$CardType")
public class CardType extends StandardEntity {

    @OneToMany(targetEntity=CardItem.class )
    private List<CardItem> cardItems;

    // skipped

In my card-item-edit.xml I have the following:

<dsContext>
    <datasource id="CardItemDs" class="com.company.tkb.entity.CardItem" view="_local"/>
    <collectionDatasource id="CardTypeDs" class="com.company.tkb.entity.CardType" view="_local">
        <query>select c from tkb$CardType c</query>
    </collectionDatasource>
</dsContext>
<layout>
    <lookupField datasource="CardItemDs" property="cardTypeName" optionsDatasource="CardTypeDs"/>

I filled the table TKB_CARD_TYPE with some values. Now I'm trying to get a drop-down list with values when I create CardItem, but the list is empty.

What could be the problem?

I would be very grateful for the information. Thanks to all.

Solution

What helped:

In CardItemEdit class I added the following:

public class CardItemEdit extends AbstractEditor<CardItem> {
    @Inject
    private Datasource<CardItem> cardItemDs;

    @Inject
    private Metadata metadata;

    @Override
    public void init(Map<String, Object> params) {
        CardItem cardItem = metadata.create(CardItem.class);
        cardItemDs.setItem(cardItem);
    }   
}

Then I changed the direction of the relationship: part of my CardItem entity:

@NamePattern("The document in the following state: %s|cardState")
@Table(name = "TKB_CARD_ITEM")
@Entity(name = "tkb$CardItem")
public class CardItem extends StandardEntity {

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "CARD_TYPE_ID")
    protected CardType cardType;

    // skipped

Part of my CardType entity:

@NamePattern("Тип входящего документа: %s | cardTypeName")
@Table(name = "TKB_CARD_TYPE")
@Entity(name = "tkb$CardType")
public class CardType extends StandardEntity {

    // skipped

I defined the dsContext and lookupField by this way:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<window xmlns="http://schemas.haulmont.com/cuba/window.xsd"
        caption="msg://editCaption"
        class="com.tkbbank.client.web.item.CardItemEdit"
        datasource="cardItemDs"
        focusComponent="fieldGroup"
        messagesPack="com.tkbbank.client.web.item">

     <dsContext>
        <datasource id="cardItemDs" class="com.tkbbank.client.entity.CardItem" allowCommit="false"/>
            <collectionDatasource id="cardTypeDs" class="com.tkbbank.client.entity.CardType" view="_local">
            <query>
                <![CDATA[select e from demo$CardType e]]>
            </query>
        </collectionDatasource>
    </dsContext>


    <dialogMode forceDialog="true" width="AUTO"/>
    <layout expand="windowActions" spacing="true">
        <fieldGroup id="fieldGroup" datasource="cardItemDs">
            <column width="500px">
                <field id="cardCreationDate" editable="false"/>
                <field id="cardType" caption="Тип документа">
                    <lookupField datasource="cardItemDs" property="cardType" optionsDatasource="cardTypeDs"/>
                </field>
                <field id="cardSubtype"/>
                <field id="cardAutoFill"/>
                <field id="cardOutcomeNumber"/>
                <field id="cardDate"/>
                <field id="cardOrganization"/>
                <field id="cardDeliveryMethod"/>
                <field id="cardAdditionalInformation"/>
                <field id="registratorName"/>
            </column>
        </fieldGroup>
        <frame id="windowActions" screen="editWindowActions"/>
    </layout>
</window>

What I see now. My card:

Interface for populating CardType with data:

Interface viewing all the documents:

Now everything is ok.

By side: very helpfull questions about "Can’t find getter for property" exception(this error is appeared also):