I'm trying to create a mapreduce chain composed of two steps. The first reduce emit key-value pairs as (key, value) where value is a list of custom object and the second mapper should read the output of the first reducer. The list is a custom ArrayWritable. Here is the relevant code:
class MyArrayWritable extends ArrayWritable {
public MyArrayWritable() {
super(Custom.class);
}
public MyArrayWritable(Writable[] values) {
super(Custom.class, values);
}
@Override
public Custom[] get() {
return (Custom[]) super.get();
}
@Override
public String toString() {
return Arrays.toString(get());
}
@Override
public void write(DataOutput arg0) throws IOException {
super.write(arg0);
}
}
Second mapper (takes custom arraywritable as value):
public static class SecondMapper extends Mapper<Text, MyArrayWritable, Text, IntWritable> {
public void map(Text key, MyArrayWritable value, Context context) throws IOException, InterruptedException {
//other code
context.write(key, myNewWritableArray);
}
}
When the second job starts, I get this error: Error: java.lang.RuntimeException: java.lang.NoSuchMethodException: Detector$MyArrayWritable.< init >()
How can I solve it? I've have already implemented the default constructor inside MyArrayWritable
