package com.ikai.mapperdemo.mappers;
import java.util.Date;
import java.util.logging.Logger;
import org.apache.hadoop.io.NullWritable;
import com.google.appengine.api.datastore.Entity;
import com.google.appengine.api.datastore.Key;
import com.google.appengine.tools.mapreduce.AppEngineMapper;
import com.google.appengine.tools.mapreduce.DatastoreMutationPool;
/**
*
* The functionality of this is exactly the same as in {@link NaiveToLowercaseMapper}.
* The advantage here is that since a {@link DatastoreMutationPool} is used, mutations
* can be done in batch, saving API calls.
*
* @author Ikai Lan
*
*/
public class PooledToLowercaseMapper extends
AppEngineMapper<Key, Entity, NullWritable, NullWritable> {
private static final Logger log = Logger
.getLogger(PooledToLowercaseMapper.class.getName());
@Override
public void map(Key key, Entity value, Context context) {
log.info("Mapping key: " + key);
if (value.hasProperty("comment")) {
String comment = (String) value.getProperty("comment");
comment = comment.toLowerCase();
value.setProperty("comment", comment);
value.setProperty("updatedAt", new Date());
DatastoreMutationPool mutationPool = this.getAppEngineContext(
context).getMutationPool();
mutationPool.put(value);
}
}
}