This manual is for an old version of Hazelcast Jet, use the latest stable version.

WriteHdfsP expects items of type Map.Entry<K,V> and writes the key and value parts to HDFS. Each processor instance creates a single file in the output path identified by the member ID and the processor ID. Unlike in MapReduce, the output files are not sorted by key and are written in the order they are received by the processor.

A similar transformation to ReadHdfsP can be done for WriteHdfsP to map the incoming items into the required format. For example:

Vertex sink = dag.newVertex("sink", WriteHdfsP.writeHdfs(jobConf, (String k) -> new Text(k),
                (Long c) -> new LongWritable(c)));

This will transform the key and value to their Writable equivalents which can be required for certain OutputFormat implementations.