Grails one-many mapping stalestaleexception on composite key

Question

I use grails 2.0.0. I have three objects Member, Product and ProductType. Member has many Products and is a one-to-many relation. Product points to ProductType (reference table) and is a many-to-one relation. My question is about deleting Products. It works in one scenario and not in another. Read on. Rough outline of the mappings below: Member.groovy: ``` class Member { Long id .... SortedSet products static hasMany = [products:Product] static mapping = { table 'T_MEMBER' id column:'MEMBER_ID'... products cascade: "all-delete-orphan" } } ``` Product.groovy: ``` class Product { Long id ProductType productType ... static belongsTo = [member:Member] static mapping = { table 'T_PRODUCT' id column:'PRODUCT_ID' member column: 'MEMBER_ID' productType column: 'PRODUCT_TYPE' ... } } ``` ProductType.groovy: ``` class ProductType { Long id .. static mapping = { table 'T_PRODUCT_TYPE' id column:'PRODUCT_TYPE', generator:'assigned' ... } } ``` I got the client service code an outline of which is…

Accepted Answer

Your Product domain class must implements `Serializable` and override methods `hashCode()` and `equals()`, this thing must be done in situations where you use composite key.

Your Product domain class must be like this

```
class Product implements Serializable {
        Long id
        ProductType productType
        ...

static mapping = {
             table 'T_PRODUCT'
             id composite:['member', 'productType']
             member column: 'MEMBER_ID'
             productType column: 'PRODUCT_TYPE'
        }

boolean equals(other) {
            if (!(other instanceof Product )) {
                return false
            }
            other.member== member && other.productType== productType
        }

int hashCode() {
            def builder = new HashCodeBuilder()
            builder.append member
            builder.append productType
            builder.toHashCode()
        }

}
```

I think this way everything will be OK.

In case of problems write.

Grails one-many mapping stalestaleexception on composite key

Solution

Problem