Getting last element from array with jsonql

[rogier_1]

Hello,

I have a JSON datasource with an array of addresses. I need tp print the last element's street1 value. here's the json:

      "addresses": [          {              "id": 19764,              "addressType": {                  "name": "HOME",                  "i18nName": "address_type.HOME.NAME",                  "i18nDescription": "address_type.HOME.DESCRIPTION"              },              "street1": "Lage Naarderweg",              "houseNumber": 54,              "houseNumberSuffix": "",              "postalCode": "1211ac",              "city": "Hilversum",              "country": {                  "id": "NL",                  "countryCode3": "NLD",                  "name": "Netherlands",                  "countryCallingCode": 31              }          },          {              "id": 19765,              "addressType": {                  "name": "HOME",                  "i18nName": "address_type.HOME.NAME",                  "i18nDescription": "address_type.HOME.DESCRIPTION"              },              "street1": "Hoge Naarderweg",              "houseNumber": 54,              "houseNumberSuffix": "",              "postalCode": "1211ac",              "city": "Hilversum",              "country": {                  "id": "NL",                  "countryCode3": "NLD",                  "name": "Netherlands",                  "countryCallingCode": 31              }          }      ],

In my field I use this syntax:

 

<field name="street1a" class="java.lang.String">  <property name="net.sf.jasperreports.jsonql.field.expression" value="person.addresses.*[-1].street1"/></field>

If I replace -1 with 0, I get the first element's street1 value: Lage Naarderweg, which is correct

If I replace -1 with 1, I get the 2nd (= last)  element's street1 value: Hoge Naarderweg, which is correct

But -1 gives me null.

According to this doc: http://jasperreports.sourceforge.net/sample.reference/jsonqldatasource/index.html, this syntax should work.

 

Anyone any ideas?

 

Rogier

 

[narcism]

The only place you could use negative indexes is inside an "Array Slice" expression. In your case that would mean having:

<field name="street1a" class="java.lang.String">  <property name="net.sf.jasperreports.jsonql.field.expression" value="person.addresses.*[-1:].street1"/></field>[/code]

 

[rogier_1]

That worked! Can you maybe tell me where I could have found this in the documentation? Maybe there are some more features I need to know of?

[narcism]

If you search for "Array Slice" in the doc that you mentioned, you will be pointed to the specific Member type column where you'll find an example with this exact expression.

For now, that is the only place where we have detailed the jsonql query language.

[rogier_1]

You are absolutely right. Actually, this part is where I found the solution of the -1. I just missed the colon. Sorry about that and thanks a lot for your help!!

[propoleopure]

That's my code (I'am using JasperReports 6.17.0.)

I would like to fetch first legalName, I tried upper code and doesn't work for me, I'am still getting a whole list.

Any idea would be welcome,

Thanks in advance

 

.......

<subDataset name="personalRef" uuid="a6159040-05bf-49fe-baf1-4aa9bf09dce1">
        <property name="com.jaspersoft.studio.data.defaultdataadapter"/>
        <queryString language="jsonql">
            <![CDATA[]]>
        </queryString>
        <field name="legalName" class="java.lang.String">
            <fieldDescription><![CDATA[legalName]]></fieldDescription>
        </field>
    </subDataset>

........

 

.........

<componentElement>
                <reportElement x="87" y="590" width="383" height="39" uuid="331a47a1-752a-4753-8250-6eb82ee51545">
                    <property name="com.jaspersoft.studio.unit.height" value="px"/>
                </reportElement>
                <jr:list xmlns:jr="http://jasperreports.sourceforge.net/jasperreports/components" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports/components http://jasperreports.sourceforge.net/xsd/components.xsd" printOrder="Vertical">
                    <datasetRun subDataset="personalRef" uuid="de4ba941-86a9-421d-bb77-992f7b046c9c">
                        <dataSourceExpression><![CDATA[((net.sf.jasperreports.engine.data.JsonQLDataSource)$P{REPORT_DATA_SOURCE}).subDataSource("personalReferences")]]></dataSourceExpression>
                    </datasetRun>
                    <jr:listContents height="39" width="383">
                        <textField>
                            <reportElement x="0" y="0" width="100" height="30" uuid="75663e58-778e-4f46-a05f-1c8208d32d16"/>
                            <textFieldExpression><![CDATA[$F{legalName}]]></textFieldExpression>
                        </textField>
                    </jr:listContents>
                </jr:list>
            </componentElement>

 

.......................

 

Ex:

{
    "customerNumber": 209548,    
    "customerCity": "Holland City",
    "customerState": "OH",    
    "personalReferences": [{
        "legalName": "COLL MEJIA",        
        "city": "11",
        "state": "5",
        "zipCode": "22",        
    },
    {
        "legalName": "PAUL HOUGHLON",
        "city": "12",
        "state": "4",
        "zipCode": "44",
        }]
}