[jira] [Updated] (TINKERPOP-1133) ScriptRecordReader should allow any class implementing RecordReader not just LineRecordReader

["Dylan Bethune-Waddell (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TINKERPOP-1133?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Dylan Bethune-Waddell updated TINKERPOP-1133:
---------------------------------------------
    Summary: ScriptRecordReader should allow any class implementing RecordReader not just LineRecordReader  (was: ScriptInputFormat should allow any class implementing RecordReader not just LineRecordReader)

> ScriptRecordReader should allow any class implementing RecordReader not just LineRecordReader
> ---------------------------------------------------------------------------------------------
>
>                 Key: TINKERPOP-1133
>                 URL: https://issues.apache.org/jira/browse/TINKERPOP-1133
>             Project: TinkerPop
>          Issue Type: Improvement
>          Components: documentation, hadoop, io
>    Affects Versions: 3.2.0-incubating, 3.1.2-incubating
>            Reporter: Dylan Bethune-Waddell
>            Priority: Minor
>
> I stuck a slightly modified {{XmlRecordReader}} class from the Apache Mahout project into {{org.apache.tinkerpop.gremlin.hadoop.structure.io.script.ScriptRecordReader}} to bulk load XML with ScriptInputFormat, which I have notes on here:
> https://github.com/dylanht/thamyris
> I'm not sure what other formats would need a custom record reader, but why not allow it and let any class that implements {{RecordReader}} feed the user's groovy script? I was thinking the config would be something like:
> {code}
> // Enum for <Format>RecordReaders TinkerPop provides, otherwise fully qualified class name
> gremlin.hadoop.scriptInputFormat.reader=XML // vs. LINE or a.b.myReader
> // omit closing angled bracket to start block split before attributes
> gremlin.hadoop.scriptInputFormat.xml.startTag=<myCustomer
> gremlin.hadoop.scriptInputFormat.xml.endTag=</myCustomer>
> // An idea for later, because the above has big issues with nested elements
> gremlin.hadoop.scriptInputFormat.xml.xpath=/top/customer[position()<3]
> {code}
> Hadoop's {{RecordReader}} interface has {{InterruptedException}} checked for several methods, whereas {{LineRecordReader}} doesn't throw it for the respective methods. That's fine if {{LineRecordReader}} is imported directly as it is now, or {{XmlRecordReader}} is a weird hidden inner class the way I had it before. But to initialize anything that implements {{RecordReader}}, it seems {{LineRecordReader}} and {{XmlRecordReader}} both have to end up in the org.apache.tinkerpop.gremlin.hadoop.structure.io.script package with something like this added in:
> {code}
> // same for nextKeyValue, getCurrentKey, getCurrentValue, getProgress
> public void initialize() throws IOException, InterruptedException {
>     // doesn't enclose things in a try/catch as is
>     try { // things } catch (InterruptedException e) {
>             Thread.currentThread().interrupt();
>             throw new RuntimeException(e.getMessage(), e);
>         }
> }
> {code}
> I don't know how good an idea pulling {{LineRecordReader}} and {{XmlRecordReader}} into that package is, or how to handle the InterruptedException, and if there are more useful "<Format>RecordReader" classes that could be implemented I would like to know about them, so I thought I would throw this up here before trying a PR. What do you think?
> References:
> https://github.com/apache/hadoop/blob/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/RecordReader.java
> https://github.com/apache/hadoop/blob/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/input/LineRecordReader.java



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