UniqueConstraintValidator.cls

/**
 * Created by sonal on 2024-01-01.
 */

/**
 * Validate unique constraints on Salesforce objects. It accepts a list of records and checks if there are
 * any duplicate records based on the fields specified in the constructor.
 * The SObjectType represents the type of Salesforce object that the class will work with, and the list of
 * fields represents the fields that should be unique.
 */
public with sharing class UniqueConstraintValidator {

    private SObjectType objectAPIName;
    private List<String> fields;
    private Map<String, SObjectField> sObjectFieldMap;

    public UniqueConstraintValidator(String sObjectName, List<String> fields) {
        this.objectAPIName = Schema.getGlobalDescribe().get(sObjectName);
        this.fields = fields;
        this.sObjectFieldMap = objectAPIName.getDescribe().fields.getMap();
    }

    public void validateUniqueConstraint(List<SObject> records) {
        Map<String, Set<String>> fieldValuesMap = new Map<String, Set<String>>();
        List<String> fieldLabels = new List<String>();
        for (String field : fields) {
            fieldValuesMap.put(field, new Set<String>());
            fieldLabels.add(sObjectFieldMap.get(field).getDescribe().getLabel());
        }

        Map<String, SObject> constraintMap = new Map<String, SObject>();
        List<SObject> recordsWithDuplicateCombinations = new List<SObject>();
        for (SObject record : records) {
            String combination = getCombinationString(record);

            if (constraintMap.containsKey(combination)) {
                recordsWithDuplicateCombinations.add(record);
            } else {
                for (String field : fields) {
                    fieldValuesMap.get(field).add(String.valueOf(record.get(field)));
                }
                constraintMap.put(combination, record);
            }
        }

        List<SObject> existingRecords = executeQuery(fieldValuesMap);

        for (SObject existingRecord : existingRecords) {
            String combination = getCombinationString(existingRecord);

            if (constraintMap.containsKey(combination)) {
                recordsWithDuplicateCombinations.add(constraintMap.get(combination));
            }
        }

        for (SObject record : recordsWithDuplicateCombinations) {
            record.addError(
                String.format(
                    'Duplicate record detected with the same constraint of fields: {0}.',
                    new List<String>{ String.join(fieldLabels, ', ') }
                )
            );
        }
    }

    private String getCombinationString(SObject record) {
        String combination = '';
        for (String field : fields) {
            String fieldValue = String.valueOf(record.get(field));
            combination += fieldValue + '-';
        }
        return combination.substring(0, combination.length() - 1);
    }

    private List<SObject> executeQuery(Map<String, Object> fieldValuesMap) {
        String query = 'SELECT Id, ' + String.join(fields, ', ') + ' FROM ' + objectAPIName + ' WHERE ';
        for (String field : fields) {
            query += field + ' IN :' + field + ' AND ';
        }
        query = query.substring(0, query.length() - 5);

        Map<String, Object> queryBinds = new Map<String, Object>();
        for (String field : fields) {
            queryBinds.put(field, fieldValuesMap.get(field));
        }

        return Database.queryWithBinds(query, queryBinds, AccessLevel.USER_MODE);

    }
}