Query Builder

• QueryBuilder is an API used to build Queries for Query Engine.

• The generated queries are compatible with HTML forms also.

• Allows us to add and remove conditions

• Allows us to copy and paste of Queries

•  Easily extensible

• This QueryBuilder resides at server side and accepts a query description, creates and runs an XPath query.

• The Query Description is simply a set of predicates.

• Predicates are nothing but conditions. For each predicate type there is an evaluator component PredicateEvaluator that knows how to handle that specific predicate for XPath, filtering and facet extraction.
• Standard Predicates:
  •  path
  •  property
  • type
  • fulltext
  •  range
  •  daterange
  • nodename
  •  similar
  • tagid & tag
  • language
  • event
  •  Also we can have the following predicates: 
  • group of predicates
  • like brackets 
• order by predicates
• 
  Example usages
  
  
   From HTTP Form Post Request:

   Session session = request.getResourceResolver().adaptTo(Session.class);
   Query query = queryBuilder.createQuery(PredicateGroup.create(request.getParameterMap()), session);
   SearchResult result = query.getResult();
   ...
   

  From key/value map:

   Map map = new HashMap();
   map.put("path", "/content");
   map.put("type", "nt:file");
   Query query = builder.createQuery(PredicateGroup.create(map), session);
   SearchResult result = query.getResult();
   ...
   

  From predicates:

   PredicateGroup group = new PredicateGroup();
   group.add(new Predicate("mypath", "path").set("path", "/content"));
   group.add(new Predicate("mytype", "type").set("type", "nt:file"));
   Query query = builder.createQuery(group, session);
   SearchResult result = query.getResult();
   ...
  

QueryBuilder Debugger:

You can test and debug the queries at this URL

http://localhost:4502/libs/cq/search/content/querydebug.html

Sample Application that retrieves the images from a DAM

<%@include file="/libs/foundation/global.jsp"%><%

%><%@page session="false"%>

<%@page import="com.day.cq.tagging.*, com.day.cq.wcm.api.*" %>

<%@page

import ="java.util.*,

javax.jcr.*,

org.apache.sling.api.resource.*,

org.apache.sling.api.scripting.*,

org.apache.sling.jcr.api.*,

com.day.cq.search.*,

com.day.cq.dam.api.Asset,

com.day.cq.search.result.*"

%>

<%        SlingRepository slingRep=sling.getService (SlingRepository.class);

            Session session=slingRep.loginAdministrative (null);

            //Instantiation of Map Object useful for storing the Query Description

Map<String, String> map=new HashMap<String, String>();

QueryBuilder queryBuilder;

            //Writing Query Description that goes to form a Query

map.put ("type", "dam:Asset");

map.put ("property", "jcr:content/metadata/dc:format");

map.put ("property.value", "image/jpeg");

            //resource resolving

queryBuilder=resource.getResourceResolver ().adaptTo(QueryBuilder.class);

            //creating query based on the Query Description

Query query=queryBuilder.createQuery (PredicateGroup.create(map),session);

            //Getting and storing the Results

SearchResult searchRes=query.getResult ();

String assPath=null;

            //Iterating for the no of times the requested resource found

for (Hit hit:searchRes.getHits()){

                       //Storing the path where the resource found

           String path1=hit.getPath ();

                       //Getting the resource from the path found

           Resource rs=resourceResolver.getResource (path1);

                       //Storing the resource into Asset object

          Asset asset=rs.adaptTo (Asset.class);

                      //Getting the path from the Asset object where the fetched data stored

          assPath=asset.getPath();

                      //finally rendering the asset data on the Page

             %><img src="<%=asset.getRendition ("cq5dam.thumbnail.140.100.png").getPath() %>" ></img>
<%

}

%>