/**
* This software is licensed to you under the Apache License, Version 2.0 (the
* "Apache License").
*
* LinkedIn's contributions are made under the Apache License. If you contribute
* to the Software, the contributions will be deemed to have been made under the
* Apache License, unless you expressly indicate otherwise. Please do not make any
* contributions that would be inconsistent with the Apache License.
*
* You may obtain a copy of the Apache License at http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, this software
* distributed under the Apache License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the Apache
* License for the specific language governing permissions and limitations for the
* software governed under the Apache License.
*
* © 2012 LinkedIn Corp. All Rights Reserved.
*/
package com.senseidb.search.req.mapred.functions;
import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
import java.util.List;
import org.json.JSONException;
import org.json.JSONObject;
import com.senseidb.search.req.mapred.CombinerStage;
import com.senseidb.search.req.mapred.FacetCountAccessor;
import com.senseidb.search.req.mapred.FieldAccessor;
import com.senseidb.search.req.mapred.SenseiMapReduce;
import com.senseidb.util.JSONUtil.FastJSONArray;
import com.senseidb.util.JSONUtil.FastJSONObject;
public class DistinctCountMapReduce implements SenseiMapReduce<LongOpenHashSet, Integer> {
private String column;
@Override
public void init(JSONObject params) {
column = params.optString("column");
if (column == null) {
throw new IllegalStateException("Column parameter shouldn't be null");
}
}
@Override
public LongOpenHashSet map(int[] docId, int docIdCount, long[] uids, FieldAccessor accessor, FacetCountAccessor facetCountAccessor) {
LongOpenHashSet hashSet = new LongOpenHashSet(docIdCount);
for (int i =0; i < docIdCount; i++) {
hashSet.add(accessor.getLong(column, docId[i]));
}
return hashSet;
}
@Override
public List<LongOpenHashSet> combine(List<LongOpenHashSet> mapResults, CombinerStage combinerStage) {
if (mapResults.isEmpty()) {
return mapResults;
}
LongOpenHashSet ret = mapResults.get(0);
for (int i = 1; i < mapResults.size(); i++) {
ret.addAll(mapResults.get(i));
}
mapResults.clear();
mapResults.add(ret);
return mapResults;
}
@Override
public Integer reduce(List<LongOpenHashSet> combineResults) {
if (combineResults.isEmpty()) {
return 0;
}
LongOpenHashSet ret = combineResults.get(0);
for (int i = 1; i < combineResults.size(); i++) {
ret.addAll(combineResults.get(i));
}
return ret.size();
}
@Override
public JSONObject render(Integer reduceResult) {
// TODO Auto-generated method stub
try {
return new FastJSONObject().put("distinctCount", reduceResult);
} catch (JSONException ex) {
throw new RuntimeException(ex);
}
}
@Override
public String[] getColumns() {
return new String[]{column};
}
}