[PIG-517] Custom Loader Function which takes in a constructor argument fails during typecast

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.2.0
• Fix Version/s: 0.2.0
• Assignee: Pradeep Kamath
• Reporter: Viraj Bhat
• Created: 04/Nov/08 19:26
• Updated: 24/Mar/10 22:04
• Resolved: 10/Nov/08 20:28

Description

I have a custom loader function, known as RegexLoader that parses a line of input into fields using regex and then sets the fields. This RegexLoader extends Utf8StorageConverter and implements the LoadFunc. It takes in a constructor argument a regex string supplied by the user.
The following piece of code, works when the loaded fields are not typecasted.

REGISTER pigudf2.0/java/build/loader.jar
fullfile = load 'phonenumber.txt'
               using loader.RegexLoader('4*8')
               as   (a,z,n) ;
-- project required fields
phonerecords = foreach fullfile {
          generate
           a                as area,
           z               as zone,
           n               as number;
        }
dump phonerecords;

But when the alias a is cast to int, the piece of script fails with the error java.io.IOException: Unable to open iterator for alias: phonerecords [Unable to store for alias: phonerecords [could not instantiate 'loader.RegexLoader' with arguments 'null']]

REGISTER pigudf2.0/java/build/loader.jar
fullfile = load 'phonenumber.txt'
             using loader.RegexLoader('4*8')
        as   (a,z,n) ;
-- project required fields
phonerecords = foreach fullfile {
          generate
           (int)a          as area,
           z               as zone,
           n               as number;
        }
dump phonerecords;

Full stack trace of the error:
==================================================================================================================
java.io.IOException: Unable to open iterator for alias: phonerecords [Unable to store for alias: phonerecords [could not instantiate 'loader.RegexLoader' with arguments 'null']]
at org.apache.pig.impl.PigContext.instantiateFuncFromSpec(PigContext.java:448)
at org.apache.pig.impl.PigContext.instantiateFuncFromSpec(PigContext.java:454)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POCast.instantiateFunc(POCast.java:67)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POCast.setLoadFSpec(POCast.java:73)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.LogToPhyTranslationVisitor.visit(LogToPhyTranslationVisitor.java:1157)
at org.apache.pig.impl.logicalLayer.LOCast.visit(LOCast.java:60)
at org.apache.pig.impl.logicalLayer.LOCast.visit(LOCast.java:28)
at org.apache.pig.impl.plan.DependencyOrderWalkerWOSeenChk.walk(DependencyOrderWalkerWOSeenChk.java:68)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.LogToPhyTranslationVisitor.visit(LogToPhyTranslationVisitor.java:805)
at org.apache.pig.impl.logicalLayer.LOForEach.visit(LOForEach.java:121)
at org.apache.pig.impl.logicalLayer.LOForEach.visit(LOForEach.java:40)
at org.apache.pig.impl.plan.DependencyOrderWalker.walk(DependencyOrderWalker.java:68)
at org.apache.pig.impl.plan.PlanVisitor.visit(PlanVisitor.java:51)
at org.apache.pig.backend.hadoop.executionengine.HExecutionEngine.compile(HExecutionEngine.java:232)
at org.apache.pig.PigServer.compilePp(PigServer.java:731)
at org.apache.pig.PigServer.executeCompiledLogicalPlan(PigServer.java:644)
at org.apache.pig.PigServer.store(PigServer.java:452)
at org.apache.pig.PigServer.store(PigServer.java:421)
at org.apache.pig.PigServer.openIterator(PigServer.java:384)
at org.apache.pig.tools.grunt.GruntParser.processDump(GruntParser.java:269)
at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:178)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:84)
at org.apache.pig.tools.grunt.Grunt.exec(Grunt.java:64)
at org.apache.pig.Main.main(Main.java:306)
Caused by: java.io.IOException: Unable to store for alias: phonerecords [could not instantiate 'loader.RegexLoader' with arguments 'null']
... 24 more
Caused by: java.lang.RuntimeException: could not instantiate 'loader.RegexLoader' with arguments 'null'
... 24 more
Caused by: java.lang.InstantiationException: loader.RegexLoader
at java.lang.Class.newInstance0(Class.java:340)
at java.lang.Class.newInstance(Class.java:308)
at org.apache.pig.impl.PigContext.instantiateFuncFromSpec(PigContext.java:418)
... 23 more
==================================================================================================================
Attaching the custom RegexLoader with this Jira