applications/product/servicedef/services_rental.xml

<?xml version="1.0" encoding="UTF-8" ?>
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<services xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="http://ofbiz.apache.org/dtds/services.xsd">
    <description>Product Component Services</description>

    <service name="createFixedAssetAndLinkToProduct" default-entity-name="FixedAsset" engine="simple"
                location="component://product/minilang/product/rental/RentalServices.xml" invoke="createFixedAssetAndLinkToProduct" auth="true">
        <description>Create an FixedAsset and link to an existing product to ease rental products creation</description>
        <attribute name="productId" mode="IN" type="String"/>
        <auto-attributes include="pk" mode="INOUT" optional="true"/>
        <auto-attributes include="nonpk" mode="IN" optional="true"/>
    </service>

    <service name="getProductFirstRelatedFixedAsset" engine="simple"
                location="component://product/minilang/product/rental/RentalServices.xml" invoke="getProductFirstRelatedFixedAsset" auth="true">
        <description>Most rental products are associated with one fixed asset only, this service will return the first genericValue fixedAsset</description>
        <attribute name="productId" mode="INOUT" type="String"/>
        <attribute name="fixedAssetId" mode="OUT" type="String" optional="true"/>
    </service>
</services>