Serializing Forms

The DDM IO API serializes and deserializes forms using a request/response structure. The example here creates a serializer for saving form data in YAML format. The same principles shown here apply to writing a deserializer.

To serialize form data into YAML:

  1. Create a class that implements DDMFormSerializer:

    @Component(immediate = true, property = "ddm.form.serializer.type=yaml") public
    class DDMFormYamlSerializer implements DDMFormSerializer { .....  }

    The property ddm.form.serializer.type=yaml marks the Component so that DDMFormSerializerTracker can find the YAML serializer.

  2. Add the serializing logic to the overridden serialize method. It takes a DDMFormSerializerSerializeRequest and returns a DDMFormSerializerSerializeResponse with the serialized string in it.

    @Override public DDMFormSerializerSerializeResponse serialize(
    DDMFormSerializerSerializeRequest ddmFormSerializerSerializeRequest) {
            DDMForm ddmForm = ddmFormSerializerSerializeRequest.getDDMForm(); 
            DDMFormSerializerSerializeResponse.Builder builder = 
            return; }

This is what you need to create your serializer. Of course, YOUR CODE FOR BUILDING A YAML OBJECT GOES HERE requires some explanation. While you can do whatever you want here, there are several things you really ought to do:

Add the available Language IDs: Since you have the DDMForm object from the request, call ddmForm.getAvailableLocales().

Add the default Language ID: Get this from the DDMForm object by calling ddmForm.getDefaultLocale().

Add the Form Fields: Get these from the DDMForm object by calling ddmForm.getDDMFormFields().

Add any Form Rules: Get them form the DDMForm object with ddmForm.getDDMFormRules().

Add Success Page Settings: Get these from the DDMForm with ddmForm.getDDMFormSuccessPageSettings().

All these are done in the default form serializer, DDMFormJSONSerializer.

If you have the Liferay DXP source code, you can find the default serializer in


You didn’t create serialization code for no reason. You’ll want to call it from somewhere.

Calling the Serializer

To get properly serialized form content, follow these steps:

  1. Get the serializer from the DDMFormSerializerTracker, passing in the value of the ddm.form.serializer.type property.

  2. Construct a DDMFormSerializerSerializeRequest object using its nested static Builder class.

  3. Call the serialize method you wrote in the last section to create the DDMFormSerializerSerializeResponse, passing the DDMFormSerializerSerializeRequest object, via a call to the Builder’s build method.

  4. Get the serialized form content from the DDMFormSerializerSerializeResponse by calling its getContent method.

Here’s a code example:

DDMFormSerializer ddmFormSerializer =

DDMFormSerializerSerializeRequest.Builder builder =

DDMFormSerializerSerializeResponse ddmFormSerializerSerializeResponse =


You can create a serializer for any format that can be saved in the database as a String. Once you create the serializer, make it the default by changing the storage format in the Form’s Settings menu.

« Form Serialization with the DDM IO APIIntroduction to Localization »
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