KIE Community

List available query definitions available in the system

List<TaskInstance> tasks = queryClient.query("getAllTaskInstancesWithCustomVariables", "UserTasks", 0, 10, TaskInstance.class);
System.out.println(tasks);

this will return task instances directly from the data set without any filtering and use UserTasks mapper to build up object representation and apply paging – first page and 10 results at most.

Now it’s time to use more advanced queries capabilities and start filtering by process variables. As described in the Advanced queries in jBPM 6.4 article to be able to map custom variables we need to provide their column mapping – name and type. Following is an example that searches for tasks that:

• processInstanceId is between 1000 and 2000 – number range condition
• price is over 800 – number comparison condition
• sale date is between 01.02.2016 and 01.03.2016 – date range condition
• product in sale are EAP or Wildfly – logical and group condition
• order descending by saleDate and country

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
              
Date from = sdf.parse("2016-02-01");                        
Date to = sdf.parse("2016-03-01");
        
QueryFilterSpec spec = new QueryFilterSpecBuilder()
   .between("processInstanceId", 1000, 2000)
   .greaterThan("price", 800)
   .between("saleDate", from, to)
   .in("productCode", Arrays.asList("EAP", "WILDFLY"))
   .oderBy("saleDate, country", false)
 .addColumnMapping("COUNTRY", "string")
 .addColumnMapping("PRODUCTCODE", "string")
 .addColumnMapping("QUANTITY", "integer")
 .addColumnMapping("PRICE", "double")
 .addColumnMapping("SALEDATE", "date")
.get();        
        
List<TaskInstance> tasks = queryClient.query("getAllTaskInstancesWithCustomVariables", "UserTasksWithCustomVariables", spec, 0, 10, TaskInstance.class);
System.out.println(tasks);

public class TestQueryParamBuilder implements QueryParamBuilder<ColumnFilter> {

    private Map<String, Object> parameters;
    private boolean built = false;
    public TestQueryParamBuilder(Map<String, Object> parameters) {
        this.parameters = parameters;
    }
    
    @Override
    public ColumnFilter build() {
        // return null if it was already invoked
        if (built) {
            return null;
        }
        
        String columnName = "processInstanceId";
        
        ColumnFilter filter = FilterFactory.OR(
                FilterFactory.greaterOrEqualsTo(((Number)parameters.get("min")).longValue()),
                FilterFactory.lowerOrEqualsTo(((Number)parameters.get("max")).longValue()));
        filter.setColumnId(columnName);
       
        built = true;
        return filter;
    }

}

public class TestQueryParamBuilderFactory implements QueryParamBuilderFactory {

    @Override
    public boolean accept(String identifier) {
        if ("test".equalsIgnoreCase(identifier)) {
            return true;
        }
        return false;
    }

    @Override
    public QueryParamBuilder newInstance(Map<String, Object> parameters) {
        return new TestQueryParamBuilder(parameters);
    }

}

META-INF/services/org.jbpm.services.api.query.QueryParamBuilderFactory

where the content of this file is fully qualified class name of the factory.

with this we can issue a request that will make use of newly created query builder for advanced filters:

Map<String, Object> params = new HashMaplt;String, Object>();
params.put("min", 10);
params.put("max", 20);

Listlt;TaskInstance> instances = queryClient.query("getAllTaskInstancesWithCustomVariables", "UserTasksWithCustomVariables", "test", params, 0, 10, TaskInstance.class);

So what we have done here:

• reference registered query by name – getAllTaskInstancesWithCustomVariables
• reference mapper by name – UserTasksWithCustomVariables
• reference query param builder identifier – test
• sent params (min and max) that will be used by new instance of query builder before query is executed

public class ProductSaleQueryMapper extends UserTaskInstanceWithCustomVarsQueryMapper {

    private static final long serialVersionUID = 3299692663640707607L;

    public ProductSaleQueryMapper() {
        super(getVariableMapping());
    }

    protected static Map<String, String> getVariableMapping() {
        Map<String, String> variablesMap = new HashMap<String, String>();
        
        variablesMap.put("COUNTRY", "string");
        variablesMap.put("PRODUCTCODE", "string");
        variablesMap.put("QUANTITY", "integer");
        variablesMap.put("PRICE", "double");
        variablesMap.put("SALEDATE", "date");
        
        return variablesMap;
    }

    @Override
    public String getName() {
        return "ProductSale";
    }
}

Here we simply extend the UserTaskInstanceWithCustomVarsQueryMapper and provide directly column mapping so it can be used without column mapping on request level. To be able to use it, mapper needs to be made discoverable so we need to create service file within META-INF folder of the jar that will package this implementation.

META-INF/services/org.jbpm.services.api.query.QueryResultMapper

where the content of this file is fully qualified class name of the mapper.

Now we can directly use it by referencing it by name:

List<TaskInstance> tasks = queryClient.query("getAllTaskInstancesWithCustomVariables", "ProductSale", 0, 10, TaskInstance.class);
System.out.println(tasks);

Raw REST API use of described examples

Get query definitions

Register query definition

Query for tasks – no filtering

Query with filter spec

Query with custom query param builder

Query for tasks – custom mapper

With this, we have went over support for advanced queries in KIE Server for BPM capability.

As usual, feedback is welcome 🙂