The instances of Hadoop MapReduce
key types should have the ability to compare against each other for sorting purposes. In order to be used as a
key type in a MapReduce computation, a Hadoop
Writable data type should implement the
org.apache.hadoop.io.WritableComparable<T> interface. The
WritableComparable interface extends the
org.apache.hadoop.io.Writable interface and adds the
compareTo() method to perform the comparisons.
In this recipe, we modify the
LogWritable data type of the Implementing a custom Hadoop Writable data type recipe to implement the
The following are the steps to implement a custom Hadoop
WritableComparable data type for the HTTP server log entries, ...