FlutterArtist FilterModelStructure ex2

registerFilterModelStructure
specifyDefaultValueForMultiOptTildeCriterion()

Note: The article you are viewing is example Demo59b, a minor upgrade from example Demo59a, which adds some configurations so that TildeFilterCriterion(s) are set to default values instead of manual user operations on the FilterPanel.
FlutterArtist FilterModelStructure ex1

You see, when you select a new Company, the list of Department(s) will change accordingly, and a particular Department will be selected by default.

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Similar to example Demo59a, the following is the Field-Based JSON structure you will receive to send to the server for querying and filtering employees.

{
    "connector": "AND",
    "conditions": [
        {
            "field": "searchText",
            "operator": "containsIgnoreCase",
            "value": null
        },
        {
            "connector": "OR",
            "conditions": [
                {
                    "field": "departmentId",
                    "operator": "equalTo",
                    "value": 4
                },
                {
                    "field": "departmentId",
                    "operator": "equalTo",
                    "value": 3
                }
            ]
        }
    ]
}

1. registerFilterModelStructure

First, let's look at the complete code for the defineFilterModelStructure() method.

Employee59bFilterModel.defineFilterModelStructure()

@override
FilterModelStructure defineFilterModelStructure() {
  return FilterModelStructure(
    criteriaStructure: FilterCriteriaStructure(
      simpleCriterionDefs: [
        SimpleFilterCriterionDef<String>(criterionBaseName: "searchText"),
      ],
      multiOptCriterionDefs: [
        // Multi Options Single Selection Criterion.
        MultiOptFilterCriterionDef<CompanyInfo>.singleSelection(
          criterionBaseName: "company",
          fieldName: 'companyId',
          toFieldValue: (CompanyInfo? rawValue) {
            return SimpleVal.ofInt(rawValue?.id);
          },
          tildeCriterionConfigs: [
            TildeCriterionConfig(
              suffix: '~1', // company~1
              defaultSettingPolicy: DefaultSettingPolicy.onEveryLoad,
            ),
            TildeCriterionConfig(
              suffix: '~2', // company~2
              defaultSettingPolicy: DefaultSettingPolicy.onEveryLoad,
            ),
          ],
          children: [
            // Multi Options Single Selection Criterion.
            MultiOptFilterCriterionDef<DepartmentInfo>.singleSelection(
              criterionBaseName: "department",
              fieldName: 'departmentId',
              toFieldValue: (DepartmentInfo? rawValue) {
                return SimpleVal.ofInt(rawValue?.id);
              },
              tildeCriterionConfigs: [
                TildeCriterionConfig(
                  suffix: '~1', // department~1
                  defaultSettingPolicy: DefaultSettingPolicy.onEveryLoad,
                ),
              ],
            ),
          ],
        ),
      ],
    ),
    conditionStructure: FilterConditionStructure(
      connector: FilterConnector.and,
      conditionDefs: [
        FilterConditionDef.simple(
          tildeCriterionName: "searchText~",
          operator: FilterOperator.containsIgnoreCase,
        ),
        FilterConditionDef.group(
          groupName: 'G2',
          connector: FilterConnector.or,
          conditionDefs: [
            FilterConditionDef.simple(
              tildeCriterionName: "department~1",
              operator: FilterOperator.equalTo,
            ),
            FilterConditionDef.simple(
              tildeCriterionName: "department~2",
              operator: FilterOperator.equalTo,
            ),
          ],
        ),
      ],
    ),
  );
}

tildeCriterionConfigs

Similar to example Demo59a, there will be two TildeCriterion(s) - "company~1" and "company~2" created based on the Criterion("company") blueprint.

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And here's how to configure the two TildeCriterion(s) mentioned above:

MultiOptCriterionDef<CompanyInfo>

MultiOptFilterCriterionDef<CompanyInfo>.singleSelection(
  criterionBaseName: "company",
  fieldName: 'companyId',
  toFieldValue: (CompanyInfo? rawValue) {
    return SimpleVal.ofInt(rawValue?.id);
  },
  tildeCriterionConfigs: [
    TildeCriterionConfig(
      suffix: '~1', // company~1
      defaultSettingPolicy: DefaultSettingPolicy.onEveryLoad,
    ),
    TildeCriterionConfig(
      suffix: '~2', // company~2
      defaultSettingPolicy: DefaultSettingPolicy.onEveryLoad,
    ),
  ],
  ...
}

By default, TildeFilterCriterion(s) are only assigned default values the first time they are initialized. In other words, their default configuration is like this:

(Default Configs)

tildeCriterionConfigs: [
  TildeCriterionConfig(
    suffix: '~1', // company~1
    defaultSettingPolicy: DefaultSettingPolicy.onInitialOnly,
    parentMatchSuffix: null,
  ),
  TildeCriterionConfig(
    suffix: '~2', // company~2
    defaultSettingPolicy: DefaultSettingPolicy.onInitialOnly,
    parentMatchSuffix: null,
  ),
],

Similarly, we configure TildeFilterCriterion("department~1"). Note: TildeFilterCriterion("department~2") is not provided with a configuration, so the default configuration will be applied to it.

MultiOptTildeCriterionDef<DepartmentInfo>

MultiOptTildeCriterionDef<DepartmentInfo>.singleSelection(
  criterionBaseName: "department",
  fieldName: 'departmentId',
  toFieldValue: (DepartmentInfo? rawValue) {
    return SimpleVal.ofInt(rawValue?.id);
  },
  tildeCriterionConfigs: [
    TildeCriterionConfig(
      suffix: '~1', // department~1
      defaultSettingPolicy: DefaultSettingPolicy.onEveryLoad,
    ),
  ],
),

With the above configuration, whenever company~1 changes, department~1 will have a default value, while if company~2 changes, department~2 will be null.

2. specifyDefaultValueForMultiOptTildeCriterion()

After the data is loaded for each MultiOptTildeFilterCriterion, the assignment of a default value is determined by the specifyDefaultValueForMultiOptTildeCriterion() method:

specifyDefaultValueForMultiOptTildeCriterion()

@override
OptValueWrap? specifyDefaultValueForMultiOptTildeCriterion({
  required String multiOptTildeCriterionName,
  required String multiOptCriterionBaseName,
  required Object? parentMultiOptTildeCriterionValue,
  required SelectionType selectionType,
  required XData multiOptTildeCriterionXData,
}) {
  if (multiOptCriterionBaseName == "company") {
    var xList = multiOptTildeCriterionXData as ListXData<int, CompanyInfo>;
    CompanyInfo? companyInfo = xList.items.firstOrNull;
    return OptValueWrap.single(companyInfo);
  } else if (multiOptCriterionBaseName == "department") {
    var xList = multiOptTildeCriterionXData as ListXData<int, DepartmentInfo>;
    DepartmentInfo? departmentInfo = xList.items.firstOrNull;
    return OptValueWrap.single(departmentInfo);
  }
  return null;
}

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FlutterArtist FilterModelStructure ex2

1. registerFilterModelStructure

2. specifyDefaultValueForMultiOptTildeCriterion()

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