[SOLVED]operator.setParameter method

Ale

Hi, I'm new to rapidminer. I'm trying to execute this simple process using java code

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.013">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.3.013" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="retrieve" compatibility="5.3.013" expanded="true" height="60" name="Retrieve model" width="90" x="45" y="75">
        <parameter key="repository_entry" value="//Local Repository/data/model"/>
      </operator>
      <operator activated="true" class="retrieve" compatibility="5.3.013" expanded="true" height="60" name="Retrieve testing" width="90" x="45" y="210">
        <parameter key="repository_entry" value="//Local Repository/data/testing"/>
      </operator>
      <operator activated="true" class="apply_model" compatibility="5.3.013" expanded="true" height="76" name="Apply Model" width="90" x="313" y="75">
        <list key="application_parameters"/>
      </operator>
      <connect from_op="Retrieve model" from_port="output" to_op="Apply Model" to_port="model"/>
      <connect from_op="Retrieve testing" from_port="output" to_op="Apply Model" to_port="unlabelled data"/>
      <connect from_op="Apply Model" from_port="labelled data" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>

I need to change the repository_entry value of the two retrieve operators. I'm using the setParameter method

Operator opRetModel = process.getOperator("Retrieve model");
            opRetModel.setParameter(???,model path)

but I don't understand what to use as first parameter to specify the path of the saved model.

I've read the question n 6 at this page http://rapid-i.com/rapidforum/index.php/topic,5807.0.html but I don't understand what is that class SingleDocumentInputOperator.
Thanks for your help.

Marco_Boeck

Hi,

I have updated the question in the FAQ because the operator used was from an extension and thus not the best example.
I'll rewrite this here anyway:

Step 1) Open the "OperatorsCore.xml" file and search for the name of the operator. In your case, <key>retrieve</key> is the one you're looking for. Note how that key is the same as the 'class' attribute in the process XML. Now you know that "<class>com.rapidminer.operator.io.RepositorySource</class>" is the implementation class of the operator.
Step 2) You can then check said class for string constants and you will find "PARAMETER_REPOSITORY_ENTRY". This is the key you need to use.

Regards,
Marco

Ale

Thank you very much, now I understand how it works.
I'm still having problems calling this method when the parameter to set is the path to a file.
This code

Operator opReadModel = process.getOperator("Read model");
String path="/home/alessia/Scrivania/model.mod";
opReadModel.setParameter(com.rapidminer.operator.io.ModelLoader.PARAMETER_MODEL_FILE,path);

gives me a null pointer exception on the third row even if the path is correct and the file exists. If I execute the process through rapidminer gui with the same parameter it works  ???

Marco_Boeck

Hi,

in the 3rd row of your code the only possiblity for a NullPointerException is when "opReadModel" is null. This is also quite likely given your process xml: The operator is called "Retrieve model" in your process, not "Read model". The call "process.getOperator("name") returns null if no operator is found with the given name.

Regards,
Marco

Ale

You were right, the operator object was null.
Thank you very much.  ;D