groovy how to make 2nd groupBy and sum -

i'm having trouble of making second groupby , doing math: total , difference, total sum() positive number , diffenrence sum() negative number.

this got:

[     ["category":"beer", "name":"budweiser", "type":null, "price":50.00, "quantity":2],     ["category":"soft drink", "name":"pepsi", "type":null, "price":10.00, "quantity":5],     ["category":"soft drink", "name":"pepsi", "type":null, "price":10.00, "quantity":-5],     ["category":"soft drink", "name":"coke", "type":null, "price":10.00, "quantity":3],     ["category":"soft drink", "name":"pepsi", "type":null, "price":10.00, "quantity":7],     ["category":"alchool", "name":"smir", "type":18, "price":5.00, "quantity":1],     ["category":"alchool", "name":"smir", "type":18, "price":5.00, "quantity":-1],     ["category":"alchool", "name":"bala", "type":20, "price":5.00, "quantity":5] ] 

and i'm trying get:

[     [beer: [name: budweiser, type: null, price: 50.00, total: 2, difference: 0] ],     [softdrink: [name: coke, type: null, price: 10.00, total: 3, difference: 0],             [name: pepsi, type: null, price: 10.00, total: 12, difference: 5] ],     [achool: [name:smir, type:18, price: 5.00, total: 1, difference: 1],             [name:bala, type:20, price: 5.00, total: 5, difference: 0]] ] 

my code i'm trying:

products.groupby { it.category }.collectentries { k, v ->         [k, v.collect{ c->             [name: c.name, difference: c.quantity, total: v.quantity.sum() + math.abs(c.quantity)]         }]     } 

try :

products.groupby { it.category }.collectentries { category, product ->   [(category): product.groupby { it.name }.collect { name, p -> [     name:name,      type: p[0].type,      price:p[0].price,     total:p.quantity.sum { math.max(0, it) },     difference:p.quantity.sum { math.max(0, -it)}    ]} ]   }​ 

nb: https://groovyconsole.appspot.com/script/5093590829105152

with 'double groupby' (it's not more simple, because want rewrite nested data) :

products.groupby({ it.category }, {it.name}).collectentries { category, names ->   [(category): names.collect { name, p -> [     name:name,      type: p[0].type,      price:p[0].price,     total:p.quantity.sum { math.max(0, it) },     difference:p.quantity.sum { math.max(0, -it)}   ] } ] }