Creating a DataPageQuery REST interface

DataPageQuery is a standard resource that allows your custom Java classes to return a set of paginated data (syntax supports the notion of page size and start index for returning data in chunks to the client) to a client without defining special parameters for a GET syntax. DataPageQuery class (com.bmc.arsys.rx.services.common.DataPageQuery) represents a generic query that is executed via DataPageResource on @Get call. You can extend this class and overload execute().

DataPageQuery sample code

The following code snippet illustrates sample DataPageQuery code format:

public
abstract class DataPageQuery implements Registerable {

   /** The data page query parameters. */
   private final DataPageQueryParameters dataPageQueryParameters;
    …
  /**
     * Execute the logic of DataPageQuery.
     * @return the data page
     */
   public abstract
DataPage execute();
…
}

Creating DataPageQuery

Let us consider that there is some data source that is not available via the record service (data is not represented by a record definition). You can create a way to perform a query for network information in the form of Node data that looks as follows in JSON:

{
"count": 6,
"ip": "14.233.555.33",
"status": "Loading",
"model": "C-245Z",
"manufacturer": "C-245Z"
}

You can retrieve such data using a REST call. To retrieve data, implement a class that extends the framework class com.bmc.arsys.rx.services.common.DataPageQuery. The framework class implements the execute() method which returns an object called DataPage.

The following code snippet represents a sample DataPageQuery class:

import com.bmc.arsys.rx.services.common.DataPageQuery;
import com.bmc.arsys.rx.services.common.DataPageQueryParameters;
import com.bmc.arsys.rx.services.common.QueryPredicate;

public class NetworkDataPageQuery extends DataPageQuery {

    public class Node {
       // Define the data members to represent a network node
    }

@Override
    public DataPage execute() {

        List<Node> = getNodeData();   // Pseudo-code to represent loading or creation of Node data.

       // Process the pagesize and startindex parameters to isolate the correct
       // chunk of data in a DataPage object.
       int start = getDataPageQueryParameters().getStartIndex();
       if (start >= list.size()) {
           return new DataPage(0, new ArrayList<Node>());
        }
       int end = Math.min(start + getDataPageQueryParameters().getPageSize(), list.size());
        List<Node> page = list.subList(start, end);
       return new DataPage(page.size(), page);
    }
}

The full implementation of this class can be found in the com.example.query package in the sample code. This includes a line of registration code in the MyLibrary bundle class.

public class MyLibrary extends RxBundle {
    protected void register() {

        registerClass(NetworkDataPageQuery.class);
    . . .

You can test the code using an authenticated session in Postman and sending GET operation to the generic resource api/rx/application/datapage.

Creating a DataPageQuery REST interface

DataPageQuery sample code

Creating DataPageQuery

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