使用 SAP UI5 绘制 Business Rule Control

本文我们介绍如何将 Business Rule Control 即规则控件，嵌入到 SAP UI5 应用程序视图中。

RuleBuilder 组件是一个规则控件的容器，可以捆绑不同的可视化手段。 目前唯一可用的可视化是决策表(Decision Table)。 RuleBuilder 定义了 UI 开发者要遵循的通用规则 UI 消费模式和 API。

在这个例子中，我们创建了一个决策表，它将使用引导输入模式。

效果如下：

可以切换条件：

可以编辑 if 条件 和 then 结果：

我们在 xml 视图里，使用的控件来自命名空间 sap.rules.ui 的标准控件：RuleBuilder，types 属性为 DecisionTable

现在我们需要将 ExpressionLanguage 对象关联连接到 RuleBuilder，然后控件通过 OData 模型加载其数据。

表达式语言(Expression languages)为规则创作、规则可视化和规则内容验证提供所需的服务。 表达式语言对象提供的服务包括表达式验证、表达式解析、自动完成建议、表达式元数据和令牌的检索，以及执行运行时服务，例如获取数据对象、输出等。

特定词汇表的词汇表 OData 模型和绑定上下文路径是表达式语言的强制输入。

表达式语言对象是 RuleBuilder 对象的关联，它可以关联多个 RuleBuilder 对象。

我们可以根据项目实际要求：自定义 Page.controller.js。

设置表达式语言对象：

oExpressionLanguage = new sap.rules.ui.services.ExpressionLanguage();
oRuleBuilder.setExpressionLanguage(oExpressionLanguage);

如果使用 DMN SFEEL(Expression language 2.0)，则代码如下：

oAstExpressionLanguage = new sap.rules.ui.services.AstExpressionLanguage();
oRuleBuilder.setAstExpressionLanguage(oAstExpressionLanguage);

确保在设置表达式语言的词汇模型之前已设置数据，如图所示：

oExpressionLanguage.setData(data);
oExpressionLanguage.setModel(that.oVocabularyModel);

控制器完整代码如下：

sap.ui.define([
    'jquery.sap.global',
    'sap/ui/core/mvc/Controller',
    'sap/ui/model/odata/v2/ODataModel',
    'sap/rules/ui/services/ExpressionLanguage',   //For DMN SFEEL language, use 'AstExpressionLanguage'.
    'sap/ui/core/util/MockServer',
    'sap/m/MessageToast'
], function (jQuery, Controller, ODataModel, ExpressionLanguage, MockServer, MessageToast) {    //For DMN SFEEL language, use 'AstExpressionLanguage' instead of 'ExpressionLanguage'.
    "use strict";

    return Controller.extend("sap.rules.ui.sample.GuidedDecisionTable.Page", {

        onInit: function () {

            sap.ui.getCore().applyTheme("sap_belize");

            // apply compact density for desktop, the cozy design otherwise
            this.getView().addStyleClass(sap.ui.Device.system.desktop ? "sapUiSizeCompact" : "sapUiSizeCozy");

            var mPath = sap.ui.require.toUrl("sap/rules/ui/sample/GuidedDecisionTable") + "/";
            
            // Initialize Expression Language services
            this.oVocabularyMockServer = new MockServer({rootUri: "/sap/opu/odata/SAP/vocabulary_srv/"});
            this.oVocabularyMockServer.simulate(
                mPath + "localService/vocabulary/metadata.xml",
                {'sMockdataBaseUrl': mPath + "localService/vocabulary/mockdata/"}
            );
            this.oVocabularyMockServer.start();
            this.oVocabularyModel = new ODataModel("/sap/opu/odata/SAP/vocabulary_srv/");
            this.oExpressionLanguage = new ExpressionLanguage();               //For DMN SFEEL, use 'new AstExpressionLanguage();'.
            this.oExpressionLanguage.setModel(this.oVocabularyModel);
            this.oExpressionLanguage.setBindingContextPath("/Vocabularies('FA163E38C6481EE785F409DCAD583D43')");

            // Initialize the Rule Builder
            this.oRuleMockServer = new MockServer({rootUri: "/sap/opu/odata/SAP/RULE_SRV/"});
            this.oRuleMockServer.simulate(
                mPath + "localService/rule/metadata.xml",
                {'sMockdataBaseUrl': mPath + "localService/rule/mockdata/"}
            );

            var aRequests = this.loadRequests(mPath);
            this.oRuleMockServer.setRequests(aRequests);
            this.oRuleMockServer.start();
            this.oRuleModel = new ODataModel({
                serviceUrl: "/sap/opu/odata/SAP/RULE_SRV/",
                defaultBindingMode: sap.ui.model.BindingMode.TwoWay
            });

            var oRuleBuilder = this.byId("ruleBuilder");
            oRuleBuilder.setModel(this.oRuleModel);
            oRuleBuilder.setExpressionLanguage(this.oExpressionLanguage);
            oRuleBuilder.setBindingContextPath("/Rules(Id='FA163E38C6481EE785F409DCAD583D43',Version='000000000000000001')");
        },

        handleEditButton: function () {
            var oEditButton = this.byId("editButton");
            var oRuleBuilder = this.byId("ruleBuilder");
            var bEdit = (oEditButton.getText() === "Edit");
            oRuleBuilder.setEditable(bEdit);
            oEditButton.setText(bEdit ? "Display" : "Edit");
        },

        onAfterRendering: function () {

            // Line actions are not supported in this demo
            var oRuleBuilder = this.byId("ruleBuilder");
            var oDecisionTable = oRuleBuilder.getAggregation("_rule");
            var oToolbar = oDecisionTable.getAggregation("_toolbar");
            var arrContent = oToolbar.getContent();
            for (var i = 0; i < arrContent.length; i++) {
                if (arrContent[i].getMetadata().getName() === "sap.m.Button") {
                    arrContent[i].detachPress(arrContent[i].mEventRegistry.press[0].fFunction, arrContent[i].mEventRegistry.press[0].oListner);
                    arrContent[i].attachPress(function (oEvent) {
                            var msg = 'Line action pressed';
                            MessageToast.show(msg);
                        }
                    );
                } else if (arrContent[i].getMetadata().getName() === "sap.m.MenuButton") {
                    var oMenu = arrContent[i].getMenu();
                    oMenu.detachItemSelected(oMenu.mEventRegistry.itemSelected[1].fFunction, oMenu.mEventRegistry.itemSelected[1].oListner);
                    oMenu.attachItemSelected(function (oEvent) {
                            var msg = 'Line action pressed';
                            MessageToast.show(msg);
                        }
                    );
                }
            }

        },

        loadRequests: function (mPath) {

            // The mock server does not support 1 to 1 navigation.
            // Hence we provide the responses directly by adding custom requests to the MockServer
            var oRresponses = jQuery.sap.sjax({
                type: "GET",
                url: mPath + "localService/rule/responses.json",
                dataType: "json"
                }    
            ).data;
            
            var aRequests = this.oRuleMockServer.getRequests();
            var sMethod = "GET";
            var sPath = /Rules\(Id='FA163E38C6481EE785F409DCAD583D43',Version='000001'\)\/DecisionTable\/DecisionTableRows\/\$count/;
            var fnResponse1 = function (xhr) {
                xhr.respond(200, {
                    "Content-Type": "text/plain;charset=utf-8"
                }, "5");
            };
            aRequests.push({method: sMethod, path: sPath, response: fnResponse1});
            
            sPath = /Rules\(Id='FA163E38C6481EE785F409DCAD583D43',Version='000001'\)\/DecisionTable\/DecisionTableRows\?\$skip=0&\$top=\d+&\$orderby=Sequence%20asc&\$expand=Cells/;
            var response_1 = this.response_1;
            var fnResponse2 = function (xhr) {
                xhr.respondJSON(200, {
                    "Content-Type": "application/json;charset=utf-8"
                }, oRresponses.response_1);
            };
            aRequests.push({method: sMethod, path: sPath, response: fnResponse2});

            sPath = /Rules\(Id='FA163E38C6481EE785F409DCAD583D43',Version='000001'\)\/DecisionTable\/DecisionTableColumns\/\$count/;
            var fnResponse3 = function (xhr) {
                xhr.respond(200, {
                    "Content-Type": "text/plain;charset=utf-8"
                }, "5");
            }
            aRequests.push({method: sMethod, path: sPath, response: fnResponse3});

            sPath = /Rules\(Id='FA163E38C6481EE785F409DCAD583D43',Version='000001'\)\/DecisionTable\/DecisionTableColumns\?\$skip=0&\$top=\d+&\$expand=Condition%2cResult/;
            var response_2 = this.response_2;
            var fnResponse4 = function (xhr) {
                xhr.respondJSON(200, {
                    "Content-Type": "application/json;charset=utf-8"
                }, oRresponses.response_2);
            }
            aRequests.push({method: sMethod, path: sPath, response: fnResponse4});
 
            return aRequests;
        }
    });
});