Extract Information Component Fails when using XPath

Datadude

I'm trying to extract some data using the XPath parsing capability of the Extract Information component.  It's not going very well.  I've used the Read Document component to read a text file and now I would like to parse the document.  However, when I use the Extract Information component inside a Process Document component I'm getting an error:  java.lang.String cannot be cast to org.jdom.Text.  Changing the assume_html flags (or any other flags) doesn't seem to make any difference.

Here is my job:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.2.008">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.2.008" expanded="true" name="Process">
    <parameter key="logverbosity" value="warning"/>
    <parameter key="logfile" value="/Users/wardloving/Documents/Data Mining/log.out"/>
    <parameter key="resultfile" value="/Users/wardloving/Documents/Data Mining/results.out"/>
    <process expanded="true" height="184" width="807">
      <operator activated="true" class="text:read_document" compatibility="5.2.004" expanded="true" height="60" name="Read Document" width="90" x="62" y="49">
        <parameter key="file" value="/Users/wardloving/Documents/Projects/Churches/Episcopal Church Pages/5615.html"/>
        <parameter key="extract_text_only" value="false"/>
      </operator>
      <operator activated="true" class="text:process_documents" compatibility="5.2.004" expanded="true" height="94" name="Process Documents" width="90" x="246" y="30">
        <parameter key="create_word_vector" value="false"/>
        <parameter key="keep_text" value="true"/>
        <process expanded="true" height="206" width="708">
          <operator activated="true" class="text:extract_information" compatibility="5.2.004" expanded="true" height="60" name="Extract Information" width="90" x="112" y="30">
            <parameter key="query_type" value="XPath"/>
            <list key="string_machting_queries"/>
            <list key="regular_expression_queries"/>
            <list key="regular_region_queries"/>
            <list key="xpath_queries">
              <parameter key="Name" value="substring-before(//title, ',')"/>
              <parameter key="Staff" value="substring-before(//*[@class = 'field field-type-text field-field-clergy']/div/div/node()[not(self::div)],',')"/>
            </list>
            <list key="namespaces"/>
            <parameter key="ignore_CDATA" value="false"/>
            <list key="index_queries"/>
          </operator>
          <connect from_port="document" to_op="Extract Information" to_port="document"/>
          <connect from_op="Extract Information" from_port="document" to_port="document 1"/>
          <portSpacing port="source_document" spacing="0"/>
          <portSpacing port="sink_document 1" spacing="0"/>
          <portSpacing port="sink_document 2" spacing="0"/>
        </process>
      </operator>
      <connect from_op="Read Document" from_port="output" to_op="Process Documents" to_port="documents 1"/>
      <connect from_op="Process Documents" from_port="example set" 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>

MariusHelf

Hi,

thanks for reporting. This is a known bug which has already been fixed in the development version. We expect it to be released later this month.

Best regards,
Marius

Datadude

Still seeing this error in Version 5.3:

Feb 6, 2013 10:42:07 AM SEVERE: Process failed: operator cannot be executed (java.lang.String cannot be cast to org.jdom.Text). Check the log messages...
Feb 6, 2013 10:42:07 AM SEVERE: Here:          Extract Data Elements XPath[1] (Process)
          subprocess 'Main Process'
            +- Read Web Page[1] (Read Document)
            +- Remove Document Parts[1] (Remove Document Parts)
      ==>  +- Extract Information[1] (Extract Information)

I don't see the error if I remove the html tags from the component using the "extract text only" flag on the Read Document component.  But of course that breaks the parsing in my XPaths.  I need the tags to be able to grab the elements/data that I'm looking for.

MariusHelf

Hm, did you also upgrade the text processing extension, or only RapidMiner core? You can check that under Help -> About installed extensions...


Best regards,
Marius