Create Composite primary key from Json in Realm Database

Question

I have two field like store and barcode. I have to create a column which will work as composite primary key and will be the combination of store and barcode. But the table is being inflated from Json. I want to update the row if the combination already exists.

@PrimaryKey
private String CompositePrimaryKey


@SerializedName("barcode")
private String barcode;


public String getStoreCode() {
    return storeCode;
}

public void setStoreCode(String storeCode) {
    this.storeCode = storeCode;
}

@SerializedName("storeCode")
private String storeCode;

Not sure how to save the value form Json.