如何在绑定到客户端控件之前对SAPUI5 OData进行分组？

Question

我有一个odata列表,例如JSON表示法:

var data = [
 {"category" : "A", "value" : 1, "group" : "x"},
 {"category" : "B", "value" : 2, "group" : "y"},
 {"category" : "C", "value" : 3, "group" : "x"},
 {"category" : "A", "value" : 4, "group" : "y"},
 {"category" : "A", "value" : 5, "group" : "x"}
];

首先,我对group == x;剩下的值进行筛选:

var data = [
 {"category" : "A", "value" : 1, "group" : "x"},
 {"category" : "C", "value" : 3, "group" : "x"},
 {"category" : "A", "value" : 5, "group" : "x"}
];

现在我将按类别分组(在客户端)并总结值,因此结果应为:

var data = [
 {"category" : "A", "value" : 6, },
 {"category" : "C", "value" : 3, },
];

之后,我将模型绑定到某个SAPUI5控件.

但分组部分似乎不可能.

有人知道这个问题的通用解决方案吗？

一个潜在的用例:

var oDataset = new sap.viz.ui5.data.FlattenedDataset({
    dimensions : [ {axis : 1, value : "{category}", name : "Category" } ],
    measures : [ {value : "{value}", name : "Value" } ],
    data : {
        path : "/Data"
    }
});

var oGraph = new sap.viz.ui5.Donut({
    dataset : oDataset, // sap.viz.ui5.data.Dataset
});

Answer 1

以下代码适用于我.通过通用绑定查询一些产品的Northwind Order_Details服务,map减少返回的绑定并将每个订单的数量汇总到销售的总量,在柱形图中显示结果.

请参阅jsBin示例

注意sap.viz引入了Array.prototype.map和Array.prototype.reduce函数

var sURI = 'http://services.odata.org/Northwind/Northwind.svc/';
var oDataModel = new sap.ui.model.odata.ODataModel(sURI, true);
oDataModel.setSizeLimit(10000);
var oJSONModel = new sap.ui.model.json.JSONModel({}, 'jmodel');

// handle list of contexts
var handler = function(oEvent) {
    var mapCallback = function(oContext) {
        var obj = {};
        obj.ProductID = oContext.getObject().ProductID,
        obj.Quantity = oContext.getObject().Quantity
        return obj;
    };

    var reduceCallback = function(aPrev, oCurr) {
        var aNext = aPrev;
        var bFound = false;

        aNext.forEach(function(item) {
            if (item.ProductID === oCurr.ProductID) {
                bFound = true;
                item.Quantity += oCurr.Quantity;
            }
        })

        if (bFound === false) {
            aNext.push(oCurr);
        }

        return aNext;
    };
    //release handler
    oBindings.detachChange(handler);

    var aTotals = oEvent.oSource.getContexts().map(mapCallback).reduce(reduceCallback, []);
    oJSONModel.setData({
        'Order_Totals': aTotals
    });
};

// Filter all orders by 3 products
var oFilter1 = new sap.ui.model.Filter("ProductID", sap.ui.model.FilterOperator.EQ, '1');
var oFilter2 = new sap.ui.model.Filter("ProductID", sap.ui.model.FilterOperator.EQ, '68');
var oFilter3 = new sap.ui.model.Filter("ProductID", sap.ui.model.FilterOperator.EQ, '11');
var aFilter = [oFilter1, oFilter2, oFilter3];

// Sort by ProductID
var oSorter = new sap.ui.model.Sorter("ProductID", false, true);

// Reduce the returned payload by nominating need fields
var oSelect = {
    select: 'ProductID,Quantity'
}

var oBindings = oDataModel.bindList("/Order_Details", null, oSorter, aFilter, oSelect);

// call OData service and handle results
oBindings.attachChange(handler);
oBindings.getContexts();

var oDataset = new sap.viz.ui5.data.FlattenedDataset({
    dimensions: [{
        axis: 1,
        name: 'ProductID',
        value: "{ProductID}"
    }],
    measures: [{
        name: 'Quantity Sold',
        value: '{Quantity}'
    }],
    data: {
        path: "/Order_Totals"
    }
});

var oColumnChart = new sap.viz.ui5.Column({
    width: "80%",
    height: "400px",
    plotArea: {
        'colorPalette': d3.scale.category20().range()
    },
    title: {
        visible: true,
        text: 'Qutantity Sold by Product'
    },
    dataset: oDataset
});

oColumnChart.setModel(oJSONModel);