QueryBuilder v2

QueryBuilderV2.cls

/***************************************************************************************************
 * Copyright (c), FinancialForce.com, inc
 * All rights reserved.
 *
 * Generic Query Builder class to handle generation of SOQL queries and query exection
 * based on fflib QueryFactory
 ***************************************************************************************************/
public class QueryBuilder {

    public enum SortOrder {ASCENDING, DESCENDING}
    public Schema.SObjectType table {get; private set;}

    private Set<String> fields;
    private String conditionExpression;
    private Integer limitCount;
    private Integer offsetCount;
    private List<Ordering> order;

    private Boolean sortSelectFields = true;

    public QueryBuilder(String table) {
        this.table = Schema.getGlobalDescribe().get(table);
        fields = new Set<String>();
        order = new List<Ordering>();
    }

    /**
     * Methods for query fields
     */
    public QueryBuilder selectFields(Set<String> fields) {
        for (String fieldApiName : fields){
            this.fields.add(fieldApiName);
        }
        return this;
    }

    public Set<String> getSelectedFields() {
        return this.fields;
    }

    /**
     * Methods for query conditions
     */
    public QueryBuilder setCondition(String conditionExpression) {
        if(this.conditionExpression == NULL) {
            this.conditionExpression = conditionExpression;
        }
        else {
            this.conditionExpression += ' AND ' + conditionExpression;
        }
        return this;
    }

    public QueryBuilder setCondition(List<String> conditions) {
        if (!conditions.isEmpty()) {
            for(String condition : conditions) {
                setCondition(condition);
            }
        }
        return this;
    }

    public QueryBuilder setConditions(Map<String, String> queryFilters) {
        String[] conditions = new String[]{};
        for(String filter : queryFilters.keySet()) {
            conditions.add( filter + ' = ' + '\'' + queryFilters.get(filter) + '\'' );
        }
        for(String condition : conditions) {
            this.setCondition(condition);
        }
        return this;
    }

    public String getCondition() {
        return this.conditionExpression;
    }

    /**
     * Methods for query limit
     */
    public QueryBuilder setLimit(Integer limitCount) {
        this.limitCount = limitCount;
        return this;
    }

    public Integer getLimit() {
        return this.limitCount;
    }

    /**
     * Methods for query offset
     */
    public QueryBuilder setOffset(Integer offsetCount) {
        this.offsetCount = offsetCount;
        return this;
    }

    public Integer getOffset() {
        return this.offsetCount;
    }

    /**
     * Methods for query ordering
     */
    public QueryBuilder addOrdering(Ordering o) {
        this.order.add(o);
        return this;
    }

    public QueryBuilder addOrdering(String fieldName, SortOrder direction){
        order.add(
            new Ordering(getFieldPath(fieldName), direction)
        );
        return this;
    }

    public QueryBuilder setOrdering(Ordering o) {
        this.order = new List<Ordering>{ o };
        return this;
    }

    public QueryBuilder setOrdering(String fieldName, SortOrder direction){
        Ordering order = new Ordering(getFieldPath(fieldName), direction);
        return setOrdering(order);
    }

    public List<Ordering> getOrderings() {
        return this.order;
    }

    /**
     * Method to generate SOQL query from set parameters
     */
    public String toSOQL() {
        String result = 'SELECT ';

        if (fields.size() == 0) {
            result += 'Id';
        }
        else {
            List<String> fieldsToQuery = new List<String>(fields);
            if (sortSelectFields) {
                fieldsToQuery.sort();
            }
            result += String.join(fieldsToQuery,', ');
        }
        result += ' FROM ' + table.getDescribe().getName();

        if (conditionExpression != null) {
            result += ' WHERE ' + conditionExpression;
        }

        if (order.size() > 0) {
            result += ' ORDER BY ';
            for(Ordering o : order) {
                result += o.toSOQL() + ', ';
            }
            result = result.substring(0, result.length() - 2);
        }

        if (limitCount != null) {
            result += ' LIMIT ' + limitCount;
        }

        if (offsetCount != null) {
            result += ' OFFSET ' + offsetCount;
        }

        return result;
    }

    /**
     * Method to get field path
     */
    private String getFieldPath(String fieldName) {
        String tokenName;
        if(!fieldName.contains('.')) { //single field
            Schema.SObjectField token = table.getDescribe().fields.getMap().get(fieldName);
            if(token == null) {
                throw new InvalidFieldException(fieldName,this.table);
            }
            tokenName = token.getDescribe().getName();
        }
        return tokenName;
    }

    /**
     * Wrapper class for Ordering
     */
    public class Ordering {

        private SortOrder direction;
        private boolean nullsLast;
        private String field;

        public Ordering(String fieldApiName, SortOrder direction){
            this.direction = direction;
            this.field = fieldApiName;
            this.nullsLast = true;
        }

        public String getField(){
            return this.field;
        }

        public SortOrder getDirection(){
            return direction;
        }

        public boolean isNullsLast(){
            return nullsLast;
        }

        public String toSOQL(){
            return field
                + ' '
                + (direction == SortOrder.ASCENDING ? 'ASC' : 'DESC')
                + (nullsLast ? ' NULLS LAST ' : ' NULLS FIRST ');
        }
    }

    /**
     * Custom exception for invalid field names
     */
    public class InvalidFieldException extends Exception {

        private String fieldName;
        private Schema.SObjectType objectType;

        public InvalidFieldException(String fieldname, Schema.SObjectType objectType){
            this.objectType = objectType;
            this.fieldName = fieldName;
            this.setMessage( 'Invalid field \'' + fieldName + '\' for object \'' + objectType + '\'' );
        }
    }

}