Attempt to invoke virtual method 'boolean org.dmg.pmml.PMML.hasModels()' on a null object reference about jpmml-evaluator HOT 6 CLOSED

Looks like you have passed null argument to the NearestNeighborModelEvaluator(PMML) constructor. Have you double-checked it already?

JPMML-Evaluator works fine on Android. However, it may be a bit tricky to obtain the org.dmg.pmml.PMML class model object, because you cannot parse PMML documents using the JAXB framework. The only option is to de-serialize it from a Java serialization document.

Have you seen the JPMML-Android project?

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Sorry for the late reply but I've been testing out JPMML-Android. I've been looking over the code of JPMML-Android and I can not seem to find the part where you serialize the pmml file. How did you create the model.pmml.ser file without using JAXBUtil.unmarshalPMML() to generate the org.dmg.pmml.PMML?

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The model.pmml.ser file is generated using org.jpmml:pmml-maven-plugin Maven plugin, which is part of the JPMML-Model project. It happens during the packaging of the Android application APK.

Here's an example:
https://github.com/jpmml/jpmml-android/blob/master/pmml-android-example/pom.xml#L52

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@vruusmann Thanks for the pointer. Any idea on whether it is possible to invoke this plugin in Android Studio/gradle instead of Maven? I understand that you can put a repo url in the top-level gradle file and import a maven library in the module-level gradle file, but I am not sure if the actual transformation defined by execution can be performed using gradle.

Alternatively, do you have a pointer to a piece of code for transforming a model in PMML to SER?

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@chenguangshen The SER file is just a Java Serialization file:

org.dmg.pmml.PMML pmml = ...;
try(OutputStream os = new FileOutputStream("model.ser")){
  ObjectOutputStream oos = new ObjectOutputStream(os);
  oos.writeObject(pmml);
  oos.close();
}

For more details, see the SerMojo class that is part of the pmml-maven-module of the JPMML-Model project:
https://github.com/jpmml/jpmml-model/blob/master/pmml-maven-plugin/src/main/java/org/jpmml/model/plugin/SerMojo.java#L192

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@vruusmann Thanks, this is very helpful!

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