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The functionality of the Asset Share Query Builder is exposed through a Java API and a REST API. This section describes these APIs.

The server-side query builder (QueryBuilder) will accept a query description, create and run an XPath query, optionally filter the result set, and also extract facets, if desired.

The query description is simply a set of predicates (Predicate). Examples include a full-text predicate, which corresponds to the jcr:contains() function in XPath, and an image size predicate that looks for width and height properties in the DAM asset subtree.

For each predicate type, there is an evaluator component (PredicateEvaluator) that knows how to handle that specific predicate for XPath, filtering, and facet extraction. It is very easy to create custom evaluators, which are plugged-in through the OSGi component runtime.

The REST API provides access to exactly the same features through HTTP with responses being sent in JSON.

Note:

The QueryBuilder API is built using the JCR API. You can also query the Adobe Experience Manager JCR by using the JCR API from within an OSGi bundle. For information, see Querying Adobe Experience Manager Data using the JCR API.

Gem Session

AEM Gems is a series of technical deep dives into Adobe Experience Manager delivered by Adobe experts. This session dedicated to the query builder is very useful for an overview and use of the tool.

Note:

See the AEM Gem session Search forms made easy with the AEM querybuilder for a detailed overview of the query builder.

Sample Queries

These samples are given in Java properties style notation. To use them with the Java API, use a Java HashMap as in the API sample that follows.

For the QueryBuilder JSON Servlet, each example includes a link to your local CQ installation (at the default location, http://localhost:4502). Note that you have to log in to your CQ instance before using these links.

Caution:

By default, the query builder json servlet displays a maximum of 10 hits.

Adding the following parameter allows the servlet to display all query results:

    p.limit=-1

Note:

To view the returned JSON data in your browser you may want to use a plugin such as JSONView for Firefox.

Returning all results

The following query will return ten results (or to be precise a maximum of ten), but inform you of the Number of hits: that are actually available:

path=/content
1_property=sling:resourceType
1_property.value=foundation/components/text
1_property.operation=like
orderby=path

The same query (with the parameter p.limit=-1) will return all results (this might be a high number depending on your instance):

path=/content
1_property=sling:resourceType
1_property.value=foundation/components/text
1_property.operation=like
p.limit=-1
orderby=path

Using p.guessTotal to return the results

The purpose of the p.guessTotal parameter is to return the appropiate number of results that can be shown by combining the minimum viable p.offset and p.limit values. The advantage of using this parameter is improved performance with large result sets. This avoids calculating the full total (e.g calling result.getSize()) and reading the entire result set, optimized all the way down to the OAK engine & index. This can be a significant difference when there are 100 thousands of results, both in execution time and memory usage.

The disadvantage to the parameter is users do not see the exact total. But you can set a minimum number like p.guessTotal=1000 so it will always read up to 1000, so you get exact totals for smaller result sets, but if it's more than that, you can only show "and more".

Add p.guessTotal=true to the query below to see how it works:

http://localhost:4502/bin/querybuilder.json?path=/content&1_property=sling:resourceType&1_property.value=foundation/components/text&1_property.operation=like&p.guessTotal=true&orderby=path

 

 

path=/content
1_property=sling:resourceType
1_property.value=foundation/components/text
1_property.operation=like
p.guessTotal=true
orderby=path

The query will return the p.limit default of 10 results with a 0 offset:

"success": true,
"results": 10,
"total": 10,
"more": true,
"offset": 0,

 

 

As of AEM 6.0 SP2, you can also use a numeric value to count up to a custom number of maximum results. Use the same query as above, but change the value of p.guessTotal to 50:

http://localhost:4502/bin/querybuilder.json?path=/content&1_property=sling:resourceType&1_property.value=foundation/components/text&1_property.operation=like&p.guessTotal=50&orderby=path

It will return a numer the same default limit of 10 results with a 0 offset, but will only display a maximum of 50 results:

 

 

"success": true,
"results": 10,
"total": 50,
"more": true,
"offset": 0,

Implementing pagination

By default the Query Builder would also provide the number of hits. Depending on the result size this might take long time as determining the accurate count involves checking every result for access control. Mostly the total is used to implement pagination for the end user UI. As determining the exact count can be slow it is recommended to make use of the guessTotal feature to implement the pagination.

For example, the UI can adapt following approach:

  • Get and display the accurate count of the number of total hits (SearchResult.getTotalMatches() or total in the querybuilder.json response) are less than or equal to 100;
  • Set guessTotal to 100 while making the call to the Query Builder.
  • The response can have the following outcome:
    • total=43, more=false - Indicates that total number of hits is 43. The UI can show up to ten results as part of the first page and provide pagination for the next three pages. You can also use this implementation to display a descriptive text like "43 results found".
    • total=100, more=true - Indicates that the total number of hits is greater than 100 and the exact count is not known. The UI can show up to ten as part of the first page and provide pagination for the next ten pages. You can also use this to display a text like "more than 100 results found". As the user goes to the next pages calls made to the Query Builder would increase the limit of guessTotal and also of the offset and limit parameters.

guessTotal should also be used in cases where the UI needs to make use of infinite scrolling, in order to avoid the Query Builder from determining the exact hit count.

Find jar files and order them, newest first

type=nt:file
nodename=*.jar
orderby=@jcr:content/jcr:lastModified
orderby.sort=desc

Find all pages and order them by last modified

type=cq:Page
orderby=@jcr:content/cq:lastModified

Find all pages and order them by last modified, but descending

type=cq:Page
orderby=@jcr:content/cq:lastModified
orderby.sort=desc

Fulltext search, ordered by score

fulltext=Management
orderby=@jcr:score
orderby.sort=desc

Search for pages tagged with a certain tag

type=cq:Page
tagid=marketing:interest/product
tagid.property=jcr:content/cq:tags

Use the tagid predicate as in the example if you know the explicit tag ID.

Use the tag predicate for the tag title path (without spaces).

Because, in the previous example, you are searching for pages (cq:Page nodes), you need to use the relative path from that node for the tagid.property predicate, which is jcr:content/cq:tags. By default, the tagid.property would simply be cq:tags.

Search under multiple paths (using groups)

fulltext=Management
group.p.or=true
group.1_path=/content/geometrixx/en/company/management
group.2_path=/content/geometrixx/en/company/bod

This query uses a group (named "group"), which acts to delimit subexpressions within a query, much as parentheses do in more standard notations. For example, the previous query might be expressed in a more familiar style as:

"Management" and ("/content/geometrixx/en/company/management" or "/content/geometrixx/en/company/bod")

Inside the group in the example, the path predicate is used multiple times. To differentiate and order the two instances of the predicate (ordering is required for some predicates), you must prefix the predicates with N_ where N is the ordering index. In the previous example, the resulting predicates are 1_path and 2_path.

The p in p.or is a special delimiter indicating that what follows (in this case an or) is a parameter of the group, as opposed to a subpredicate of the group, such as 1_path.

If no p.or is given then all predicates are ANDed together, that is, each result must satisfy all predicates.

Note:

You cannot use the same numeric prefix in one single query, even for different predicates.

Search for properties

type=cq:PageContent
property=cq:template
property.value=/apps/geometrixx/templates/homepage

This has the drawback that the jcr:content nodes of the pages, not the pages themselves, are returned. To solve this, you can search by relative path:

http://localhost:4502/bin/querybuilder.json?property=jcr%3acontent%2fcq%3atemplate&property.value=%2fapps%2fgeometrixx%2ftemplates%2fhomepage&type=cq%3aPage

type=cq:Page
property=jcr:content/cq:template
property.value=/apps/geometrixx/templates/homepage

Search for multiple properties

type=cq:Page
1_property=jcr:content/cq:template
1_property.value=/apps/geometrixx/templates/homepage
2_property=jcr:content/jcr:title
2_property.value=English

Search for multiple property values

To avoid big groups when you want to search for multiple values of a property ("A" or "B" or "C"), you can provide multiple values to the property predicate:

http://localhost:4502/bin/querybuilder.json?property=jcr%3atitle&property.1_value=Products&property.2_value=Square&property.3_value=Events

property=jcr:title
property.1_value=Products
property.2_value=Square
property.3_value=Events

For multi-value properties, you can also require that multiple values match ("A" and "B" and "C"):

http://localhost:4502/bin/querybuilder.json?property=jcr%3atitle&property.and=true&property.1_value=test&property.2_value=foo&property.3_value=bar

property=jcr:title
property.and=true
property.1_value=test
property.2_value=foo
property.3_value=bar

Refining What Is Returned

By default, the QueryBuilder JSON Servlet will return a default set of properties for each node in the search result (e.g. path, name, title, etc.). In order to gain control over which properties are returned, you can do one of the following:

Specify p.hits=full, in which case all properties will be included for each node:

http://localhost:4502/bin/querybuilder.json?p.hits=full&property=jcr%3atitle&property.value=Triangle

property=jcr:title
property.value=Triangle
p.hits=full

Use p.hits=selective and specify the properties you want to get in p.properties, separated by a space:

http://localhost:4502/bin/querybuilder.json?p.hits=selective&p.properties=sling%3aresourceType%20jcr%3aprimaryType&property=jcr%3atitle&property.value=Triangle

property=jcr:title
property.value=Triangle
p.hits=selective
p.properties=sling:resourceType jcr:primaryType

Another thing you can do is include child nodes in the QueryBuilder response. In order to do this you need to specify p.nodedepth=n, where n is the number of levels you want the query to return. Note that, in order for a child node to be returned, it must be specified by the properties selector (p.hits=full). Example:

http://localhost:4502/bin/querybuilder.json?p.hits=full&p.nodedepth=5&property=jcr%3atitle&property.value=Triangle

property=jcr:title
property.value=Triangle
p.hits=full
p.nodedepth=5

More Predicates

For more predicates, see the Javadoc for the *PredicateEvaluator classes. The Javadoc for these classes contains the list of properties that you can use.

The prefix of the class name (for example, "similar" in SimilarityPredicateEvaluator) is the principal property of the class. This property is also the name of the predicate to use in the query (in lower case).

For such principal properties, you can shorten the query and use "similar=/content/en" instead of the fully qualified variant "similar.similar=/content/en". The fully qualified form must be used for all non-principal properties of a class.

Example Query Builder API Usage

   String fulltextSearchTerm = "Geometrixx";
                  
    // create query description as hash map (simplest way, same as form post)
    Map<String, String> map = new HashMap<String, String>();
  
// create query description as hash map (simplest way, same as form post)
    map.put("path", "/content");
    map.put("type", "cq:Page");
    map.put("group.p.or", "true"); // combine this group with OR
    map.put("group.1_fulltext", fulltextSearchTerm);
    map.put("group.1_fulltext.relPath", "jcr:content");
    map.put("group.2_fulltext", fulltextSearchTerm);
    map.put("group.2_fulltext.relPath", "jcr:content/@cq:tags");
 
    // can be done in map or with Query methods
    map.put("p.offset", "0"); // same as query.setStart(0) below
    map.put("p.limit", "20"); // same as query.setHitsPerPage(20) below
                    
    Query query = builder.createQuery(PredicateGroup.create(map), session);
    query.setStart(0);
    query.setHitsPerPage(20);
              
    SearchResult result = query.getResult();
 
    // paging metadata
    int hitsPerPage = result.getHits().size(); // 20 (set above) or lower
    long totalMatches = result.getTotalMatches();
    long offset = result.getStartIndex();
    long numberOfPages = totalMatches / 20;
                 
    //Place the results in XML to return to client
    DocumentBuilderFactory factory =     DocumentBuilderFactory.newInstance();
    DocumentBuilder builder = factory.newDocumentBuilder();
    Document doc = builder.newDocument();
                              
    //Start building the XML to pass back to the AEM client
    Element root = doc.createElement( "results" );
    doc.appendChild( root );
                 
    // iterating over the results
    for (Hit hit : result.getHits()) {
       String path = hit.getPath();
 
      //Create a result element
      Element resultel = doc.createElement( "result" );
      root.appendChild( resultel );
                     
      Element pathel = doc.createElement( "path" );
      pathel.appendChild( doc.createTextNode(path ) );
      resultel.appendChild( pathel );
    }

Note:

To learn how to build an OSGi bundle that uses the QueryBuilder API and use that OSGi bundle within an Adobe Experience Manager application, see Creating Adobe CQ OSGi bundles that use the Query Builder API.

Storing and loading queries

Queries can be stored to the repository so that you can use them later. The QueryBuilder provides the  storeQuery method with the following signature:

void storeQuery(Query query, String path, boolean createFile, Session session) throws RepositoryException, IOException;

When using the QueryBuilder#storeQuery method, the given Query is stored into the repository as a file or as a property according to the createFile argument value. The following example shows how to save a Query to the path /mypath/getfiles as a file:

builder.storeQuery(query, "/mypath/getfiles", true, session);

Any previously stored queries can be loaded from the repository by using the QueryBuilder#loadQuery method:

Query loadQuery(String path, Session session) throws RepositoryException, IOException

For example, a Query stored to the path /mypath/getfiles can be loaded by the following snippet:

Query loadedQuery = builder.loadQuery("/mypath/getfiles", session);

Testing and Debugging

For playing around and debugging querybuilder queries, you can use the QueryBuilder debugger console at

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

or alternatively the querybuilder json servlet at

http://localhost:4502/bin/querybuilder.json?path=/tmp

(path=/tmp is only an example).

General Debugging Recommendations

Obtain explain-able XPath via logging

Explain all queries during the development cycle against the target index set.

  • Enable DEBUG logs for QueryBuilder to obtain underlying, explainable XPath query
    • Navigate to http://serveraddress:serverport/system/console/slinglog.  Create a new logger for com.day.cq.search.impl.builder.QueryImpl at DEBUG
  • Once DEBUG has been enabled for the above class, the logs will display the XPath generated by Query Builder.
  • Copy the XPath query from the log entry for the associated QueryBuilder query, For example:
    • com.day.cq.search.impl.builder.QueryImpl XPath query: /jcr:root/content//element(*, cq:Page)[(jcr:contains(jcr:content, "Geometrixx") or jcr:contains(jcr:content/@cq:tags, "Geometrixx"))]
  • Paste the XPath query into Explain Query as XPath to obtrain the query plan

Obtain explain-able XPath via the Query Builder debugger

  • Use the AEM QueryBuilder debugger to generate an explainable XPath query:

 

Explain all queries during the development cycle against the target index set.

Obtain explain-able XPath via logging

  • Enable DEBUG logs for QueryBuilder to obtain underlying, explainable XPath query
    • Navigate to http://serveraddress:serverport/system/console/slinglog.  Create a new logger for com.day.cq.search.impl.builder.QueryImpl at DEBUG
  • Once DEBUG has been enabled for the above class, the logs will display the XPath generated by Query Builder.
  • Copy the XPath query from the log entry for the associated QueryBuilder query, For example:
    • com.day.cq.search.impl.builder.QueryImpl XPath query: /jcr:root/content//element(*, cq:Page)[(jcr:contains(jcr:content, "Geometrixx") or jcr:contains(jcr:content/@cq:tags, "Geometrixx"))]
  • Paste the XPath query into Explain Query as XPath to obtrain the query plan

Obtain explain-able XPath via the Query Builder debugger

  • Use the AEM QueryBuilder debugger to generate an explainable XPath query:

 

chlimage_1
  1. Provide the Query Buidler query in the Query Builder debugger
  2. Execute the Search
  3. Obtain the generated XPath
  4. Paste the XPath query into Explain Query as XPath to obtrain the query plan

 

Note:

Non-querybuilder queries (XPath, JCR-SQL2) can be provided directly to Explain Query.

For a rundown on how to debug queries with QueryBuilder, see the video below.

Debugging Queries with Logging

Note:

The configuration of the loggers is described in the section Creating Your Own Loggers and Writers.

The log output (INFO level) of the query builder implementation when executing the query described in Testing and Debugging:

com.day.cq.search.impl.builder.QueryImpl executing query (predicate tree):
null=group: limit=20, offset=0[
    {group=group: or=true[
        {1_fulltext=fulltext: fulltext=Geometrixx, relPath=jcr:content}
        {2_fulltext=fulltext: fulltext=Geometrixx, relPath=jcr:content/@cq:tags}
    ]}
    {path=path: path=/content}
    {type=type: type=cq:Page}
]
com.day.cq.search.impl.builder.QueryImpl XPath query: /jcr:root/content//element(*, cq:Page)[(jcr:contains(jcr:content, "Geometrixx") or jcr:contains(jcr:content/@cq:tags, "Geometrixx"))]
com.day.cq.search.impl.builder.QueryImpl no filtering predicates
com.day.cq.search.impl.builder.QueryImpl query execution took 69 ms

If you have a query using predicate evaluators that filter or that use a custom order by comparator, this will also be noted in the query:

com.day.cq.search.impl.builder.QueryImpl executing query (predicate tree):
null=group: [
    {nodename=nodename: nodename=*.jar}
    {orderby=orderby: orderby=@jcr:content/jcr:lastModified}
    {type=type: type=nt:file}
]
com.day.cq.search.impl.builder.QueryImpl custom order by comparator: jcr:content/jcr:lastModified
com.day.cq.search.impl.builder.QueryImpl XPath query: //element(*, nt:file)
com.day.cq.search.impl.builder.QueryImpl filtering predicates: {nodename=nodename: nodename=*.jar}
com.day.cq.search.impl.builder.QueryImpl query execution took 272 ms
Javadoc Description
com.day.cq.search Basic QueryBuilder and Query API
com.day.cq.search.result Result API
com.day.cq.search.facets Facets
com.day.cq.search.facets.buckets Buckets (contained within facets)
com.day.cq.search.eval Predicate Evaluators
com.day.cq.search.facets.extractors Facet Extractors (for evaluators)
com.day.cq.search.writer JSON Result Hit Writer for Querybuilder servlet (/bin/querybuilder.json)

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