Class ObjectMapper


  • public class ObjectMapper
    extends Object

    This class provides XML Document to Object mapping support.

    Transact supports marshalling data between Form XML Documents and Groovy Value Objects using the ObjectMapper class. Where possible we recommend you use the ObjectMapper for mashalling data, rather the doing this by hand which is tedious and often error prone.

    The ObjectMapper supports two use cases:

    1. creating an Groovy object graph from an XML document
    2. updating an XML document based on an Groovy object graph

    ObjectMapper Configuration

    The ObjectMapper has a number of default configurations, which can be changed with the appropriate setter methods:

    • strictMode - specified whether a missing Object field for a Document tag will throw an exception (default value true).
      Note: Disabling strict mode may bring some unpredictable behavior especially with repeats when there is total mismatch of the object and XML structure. The result could be wrong mapping of XML tags and values to objects.
    • mappingStrategy - specifies XML tag name to object mapping strategy (default value CamelUpperCase). For example '<FirstName>' XML tag will map to Object's field 'firstName'.
    • dateFormat - the date time mashalling format (default value of 'yyyy-MM-dd').

    The example below set mapping strategy to handle XML Document's tag of type 'lowerCamelCase', date format 'yyyy/dd/MM' and switch off the strict mapping mode (ignore unknown XML tag and not throw an exception).

     import com.avoka.tm.util.*
     import java.text.SimpleDateFormat
    
     new ObjectMapper()
        .setMappingStrategy(MappingStrategy.LOWER_CAMEL_CASE)
        .setDateFormat(new SimpleDateFormat("yyyy/dd/MM"))
        .setStrictMode(false) 

    Groovy Examples

    Please find the ObjectMapper examples below using the following Groovy value object classes.

     package com.maguire.vo
    
     import java.util.*
    
     class Person {
         String firstName
         String lastName
         String email
         Address currentAddress
         List<Address> previousAddresses
     }
    
     class Address {
         String line1
         String city
         Integer postCode
         String country
     } 

    The corresponding XML elements for these classes are provided below

     <Person>
         <FirstName/>
         <LastName/>
         <Email/>
         <CurrentAddress>
             <Line1/>
             <City/>
             <PostCode/>
             <Country/>
         </CurrentAddress>
         <PreviousAddresses>
             <Address>
                 <Line1/>
                 <City/>
                 <PostCode/>
                 <Country/>
             </Address>
         </PreviousAddresses>
     </Person> 

    Creating an Object Graph

    This Groovy example creates Person object from Document's xpath.

     import com.avoka.tm.util.*
     import com.maguire.vo.*
    
     Person person = new ObjectMapper()
        .setDoc(param.appDoc)
        .setFormXPath('/Person')
        .create(Person.class) 

    An example source XML document is provided below. In this example the XML repeating PreviousAddresses elements will be mapped into the Person classes List<Address> previousAddresses field.

     <?xml version="1.0"?>
     <AvokaSmartForm>
         <Person>
             <FirstName>John</FirstName>
             <LastName>Smith</LastName>
             <Email>jsmith@maguire.com</Email/>
             <CurrentAddress>
                 <Line1>12 Peterson Avenue</Line1>
                 <City>Hope Town</City>
                 <PostCode>4275</PostCode>
                 <Country/>
             </CurrentAddress>
             <PreviousAddresses>
                 <Address>
                     <Line1>30 Peace Street</Line1>
                     <City>Hope Town</City>
                     <PostCode>4276</PostCode>
                     <Country/>
                 </Address>
                 <Address>
                     <Line1>Unit 3/65 Dunkley Avenue</Line1>
                     <City>Melville</City>
                     <PostCode>5621</PostCode>
                     <Country>Australia<Country>
                 </Address>
             </PreviousAddresses>
         </Person>
     <AvokaSmartForm> 

    Repeats Support

    This Groovy example shows how to map object's repeat field with XML tag.

    In order to enable repeat support the repeat field (e.g. List<Address> previousAddresses) needs those two annotations:

    • JacksonXmlElementWrapper, which allows specifying XML element to use for wrapping, and
    • JacksonXmlProperty, which allows specifying XML local element name for a property
     package com.maguire.vo
    
     import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
     import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
    
     import java.util.*
    
     class Person {
         String firstName
         String lastName
         String email
         Address currentAddress
    
         @JacksonXmlElementWrapper(localName = "PreviousAddresses")
         @JacksonXmlProperty(localName = "Address")
         List<Address> previousAddresses
     }
    
     class Address {
         String line1
         String city
         Integer postCode
         String country
     } 

    An example source XML document is provided below.

    In this example, the XML repeating Address elements of the wrapper PreviousAddresses element will be mapped into the Person classes List<Address> previousAddresses field and each child node Address will create Address object and add to the List<Address> previousAddresses.

     <?xml version="1.0"?>
     <AvokaSmartForm>
         <Person>
             <FirstName>John</FirstName>
             <LastName>Smith</LastName>
             <Email>jsmith@maguire.com</Email/>
             <CurrentAddress>
                 <Line1>12 Peterson Avenue</Line1>
                 <City>Hope Town</City>
                 <PostCode>4275</PostCode>
                 <Country/>
             </CurrentAddress>
             <PreviousAddresses>
                 <Address>
                     <Line1>30 Peace Street</Line1>
                     <City>Hope Town</City>
                     <PostCode>4276</PostCode>
                     <Country/>
                 </Address>
                 <Address>
                     <Line1>Unit 3/65 Dunkley Avenue</Line1>
                     <City>Melville</City>
                     <PostCode>5621</PostCode>
                     <Country>Australia<Country>
                 </Address>
             </PreviousAddresses>
         </Person>
     <AvokaSmartForm> 

    Important remarks when working with repeats:

    • Root element must be a POJO but can not be a repeat
    • Refrain from disabling strict mode as it may bring some unpredictable behavior especially when there is total mismatch of the object and XML structure. The result could be wrong mapping of XML tags and values to objects.

    Updating XML Document

    This Groovy example stores Person object in the Document using the XPath '/Person'. Please note the ObjecMapper will automatically set the appropriate root XPath based on the type of document.

     import com.avoka.tm.util.*
     import com.maguire.vo.*
    
     Person person = new Person()
     person.firstName = 'Peter'
    
     new ObjectMapper()
        .setObject(person)
        .setFormXPath('/Person')
        .update(param.appDoc) 

    Object Map Field Support

    Support is also provided for Object map fields. This feature is very useful for mapping adhoc XML elements into a class Object.

    The example below has added Map customProps field.

     package com.maguire.vo
    
     import java.util.*
    
     class Person {
         String firstName
         String lastName
         String emailAddress
         Map<String, String> customProps
     } 

    XML of Primary Applicant's 'customProps' could be properties like account number, tax number, etc.

     <Person>
         <CustomProps>
             <accountNumber>12345</accountNumber>
             <taxNumber>67890</taxNumber>
         </CustomProps>
     </Person> 
     import com.avoka.tm.util.*
     import com.maguire.vo.*
    
     Person person = new ObjectMapper()
        .setDoc(param.appDoc)
        .setFormXPath('/Person')
        .create(Person.class)
    
     String accountNumber = person.customProps.get('accountNumber')
    
     // May put new property value and use update...

    Transact Function Example

    The function example below is creating an new Applicant object graph from the application document (param.appDoc).

    The example then updating the applicants address details, and then write the object graph back into the application document. Finally in the FormFuncResult result we turn on the option to return the form XML document back to the form. The JavaScript form application will then update its model with the new address details and display them to the user.

     package com.maguire.svc;
    
     import com.avoka.tm.func.*
     import com.avoka.tm.svc.*
     import com.avoka.tm.util.*
     import com.avoka.tm.vo.*
     import com.maguire.vo.*
    
     import javax.servlet.http.*
    
     public class Controller {
    
         // Injected at runtime
         public Logger logger
    
         FuncResult invoke(FuncParam param) {
    
             // Marshal formData into applicant object VO graph
             Person applicant = new ObjectMapper()
                 .setDoc(param.appDoc)
                 .setFormXPath("/Applicant")
                 .create(Person.class)
    
             logger.info("Applicant: " + applicant)
    
             // Add applicant address information
             applicant.currentAddress = new Address()
             applicant.currentAddress.line1 = "61 Main Street"
             applicant.currentAddress.city = "Avalon"
             applicant.currentAddress.postCode = "2107"
             applicant.currentAddress.country = "Australia"
    
             // Update formData with updated application object
             new ObjectMapper()
                 .setObject(applicant)
                 .setFormXPath("/Applicant")
                 .update(param.appDoc)
    
             FormFuncResult result = new FormFuncResult()
    
             // Specify formData to be returned to form
             result.includeFormData = true
    
             return result
          }
     } 

    The examples XML response document is provided below. Note in this example we have mapped the Person objects into the documents Applicant element.

     <?xml version="1.0"?>
     <AvokaSmartForm>
         <Applicant>
             <FirstName>John</FirstName>
             <LastName>Smith</LastName>
             <Email>jsmith@maguire.com</Email/>
             <CurrentAddress>
                 <Line1>61 Main Street</Line1>
                 <City>Avalon</City>
                 <PostCode>2107</PostCode>
                 <Country>Australia</Country>
             </CurrentAddress>
             <PreviousAddresses/>
         </Applicant>
     <AvokaSmartForm> 
    Since:
    17.10.0
    • Constructor Detail

      • ObjectMapper

        public ObjectMapper()
    • Method Detail

      • setDateFormat

        public ObjectMapper setDateFormat​(DateFormat dateFormat)
        Set date format. If not specified the default 'yyyy-MM-dd' date pattern will be used.
        Parameters:
        dateFormat - date format
        Returns:
        object mapper object
      • setDoc

        public ObjectMapper setDoc​(Document document)
        Set document object to create object from.
        Parameters:
        document - document object to create object from
        Returns:
        object mapper object
      • setMappingStrategy

        public ObjectMapper setMappingStrategy​(ObjectMapper.MappingStrategy mappingStrategy)
        Set mapping strategy.
        Parameters:
        mappingStrategy - mapping strategy
        Returns:
        object mapper object
      • setObject

        public ObjectMapper setObject​(Object object)
        Set object to update.
        Parameters:
        object - object to update
        Returns:
        object mapper object
      • setStrictMode

        public ObjectMapper setStrictMode​(boolean strict)
        Set strict mapping mode. If set to false, the mapper will ignore unknown XML/class properties. By default this flag is set to true.
        Parameters:
        strict - strict mapping flag
        Returns:
        object mapper object
      • setFormXPath

        public ObjectMapper setFormXPath​(String xpath)

        Set the Form XPath parameter. Any relative XPath specified will be prepended to create an absolute path.

        For documents with a <AvokaSmartForm> root node XPath expansion examples are provided below:

        FormXPathExpanded XPath
        Applicant/AvokaSmartForm/Applicant
        /Applicant/AvokaSmartForm/Applicant
        AvokaSmartForm/Applicant/AvokaSmartForm/Applicant
        /AvokaSmartForm/Applicant/AvokaSmartForm/Applicant

        For documents with a <Root> root node XPath expansion examples are provided below:

        FormXPathExpanded XPath
        Applicant/Root/AvokaSmartForm/Applicant
        /Applicant/Root/AvokaSmartForm/Applicant
        AvokaSmartForm/Applicant/Root/AvokaSmartForm/Applicant
        /AvokaSmartForm/Applicant/Root/AvokaSmartForm/Applicant

        Please note you cannot specify a // search XPath as this becomes ambiguous when setting object values back into the document.

        Parameters:
        xpath - xpath parameter
        Returns:
        object mapper object
      • setXPath

        public ObjectMapper setXPath​(String xpath)

        Set the explicit XPath parameter.

        Please note you cannot specify a // search XPath as this becomes ambiguous when setting object values back into the document.

        Parameters:
        xpath - xpath parameter
        Returns:
        object mapper object
      • create

        public <T> T create​(Class<T> type)
        Create object of the generic T type.
        Type Parameters:
        T - object type that will be created
        Parameters:
        type - object class type to create
        Returns:
        object of the generic T type
      • update

        public void update​(Document document)
        Update object of the generic T type.
        Parameters:
        document - XML document object