Salesforce Connect - Apex Adapter - query method.java

Salesforce Connect - Apex Adapter - query method.java

/**
     * This method is called everytime when SOQL is issued against external Object
     * or while using list view or viewing detail page.
     * 
     * Note : Ideally searching should be done at server side however for sake of 
     * simplicity, we would be using "DataSource.QueryUtils" class provided by
     * Salesforce. In this case, filtering and sorting would be done in Salesforce
     * once response returned by external REST API
     * */
     override global DataSource.TableResult query( DataSource.QueryContext context) {
        if (context.tableSelection.columnsSelected.size() == 1 && context.tableSelection.columnsSelected.get(0).aggregation == DataSource.QueryAggregation.COUNT) {
                List<Map<String,Object>> rows = getRows( );
                List<Map<String,Object>> response = DataSource.QueryUtils.filter(context, getRows( ));
                List<Map<String, Object>> countResponse = new List<Map<String, Object>>();
                Map<String, Object> countRow = new Map<String, Object>();
                countRow.put( context.tableSelection.columnsSelected.get(0).columnName, response.size());
                countResponse.add(countRow);
                return DataSource.TableResult.get(context, countResponse);
        } else {
            List<Map<String,Object>> filteredRows =  DataSource.QueryUtils.filter(context, getRows( ));
            List<Map<String,Object>> sortedRows = DataSource.QueryUtils.sort(context, filteredRows);
            List<Map<String,Object>> limitedRows = DataSource.QueryUtils.applyLimitAndOffset(context, sortedRows);
            return DataSource.TableResult.get(context, limitedRows);
        }
    }
    
    /**
     * Make REST callout to external system and parse the result in required format
     * */
    private List<Map<String,Object>> getRows( ){
        
        List<Map<String, Object>> lstReturnDataset =  new List<Map<String, Object>>();
        
        HttpRequest req = new HttpRequest();
        req.setEndPoint(EXTERNAL_SRC_URL);
        req.setMethod('GET');
        HttpResponse res = new Http().send(req);
        
        Map<String, Object> json_resp = ( Map<String, Object>)JSON.deserializeUntyped(res.getBody());
        
        List<Object> lstBlog = (List<Object>)json_resp.get('blog');
        
        for(Object blog : lstBlog){
            Map<String, Object> blogMap = (Map<String, Object>) blog;
            Map<String, Object> curRow = new Map<String, Object>();
            curRow.put(COL_HEADER_TITLE,blogMap.get(COL_HEADER_TITLE));
            curRow.put(COL_HEADER_SEO_KEYWORDS,blogMap.get(COL_HEADER_SEO_KEYWORDS));
            curRow.put(COL_HEADER_EXCERPT,blogMap.get(COL_HEADER_EXCERPT));
            curRow.put(COL_HEADER_CONTENT,blogMap.get(COL_HEADER_CONTENT));
            curRow.put(COL_HEADER_LANGUAGE,blogMap.get(COL_HEADER_LANGUAGE));
            curRow.put(COL_HEADER_DISPLAYURL,EXTERNAL_SRC_BASEURL+blogMap.get(COL_HEADER_BLOGLINK)); 
            curRow.put(COL_HEADER_EXTERNAL_ID, String.valueOf(blogMap.get(COL_HEADER_BLOGLINK)).replaceAll('/','_')); 
            
            lstReturnDataset.add(curRow);
        }
        
        return lstReturnDataset;
    }