Java Emitter类代码示例

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process (SAMRecordWritable input, Emitter<Pair<String, Integer >> emitter) {
    // emit each position this read overlaps

    SAMRecord record = input.get();
    Integer startPosition = record.getAlignmentStart();

    if (!record.getReadUnmappedFlag() && startPosition != null) {
        int lastInterval = -1;
        for (int i = startPosition; i < record.getAlignmentEnd(); i++) {
            int nextInterval = i / intervalSize;
            // Emit each read once for every interval it covers
            if (nextInterval != lastInterval) {
                lastInterval = nextInterval;
                emitter.emit(
                        // emit contig, interval
                        new Pair<String, Integer>(
                                record.getReferenceName(),
                                nextInterval)
                );
                // Skip length of interval or to the last base
                i = Math.min(record.getAlignmentEnd(), i + intervalSize);
            }
        }
    }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(String line, Emitter<GenericData.Record> emitter) {
  Matcher matcher = pattern.matcher(line);
  if (matcher.matches()) {
    // parse line into components
    recBuilder.set("host", asString(matcher.group(1)));
    recBuilder.set("rfc931_identity", asString(matcher.group(2)));
    recBuilder.set("username", asString(matcher.group(3)));
    recBuilder.set("datetime", asString(matcher.group(4)));
    recBuilder.set("request", asString(matcher.group(5)));
    recBuilder.set("http_status_code", asInt(matcher.group(6)));
    recBuilder.set("response_size", asInt(matcher.group(7)));
    recBuilder.set("referrer", asString(matcher.group(8)));
    recBuilder.set("user_agent", asString(matcher.group(9)));
    emitter.emit(recBuilder.build());
  } else {
    System.err.println("No match: " + line);
  }

}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(Pair<Integer, Iterable<Pair<Long, Pair<float[], LongSet>>>> input,
                    Emitter<Pair<Long, NumericIDValue>> emitter) {
  Preconditions.checkState(input.first() == getPartition(),
      "Key must match partition: %s != %s", input.first(), getPartition());
  for (Pair<Long, Pair<float[], LongSet>> value : input.second()) {
    long userID = value.first();
    float[] userFeatures = value.second().first();
    LongSet knownItemIDs = value.second().second();
    Iterable<NumericIDValue> recs = TopN.selectTopN(
        new RecommendIterator(userFeatures, partialY.entrySet().iterator(), knownItemIDs),
        numRecs);
    for (NumericIDValue rec : recs) {
      emitter.emit(Pair.of(userID, rec));
    }
  }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(String line, Emitter<Pair<Long, String>> emitter) {
  String[] columns = DelimitedDataUtils.decode(line);

  String userID = columns[0];
  String itemID = columns[1];
  long numericUserID = StringLongMapping.toLong(userID);
  long numericItemID = StringLongMapping.toLong(itemID);

  if (!Long.toString(numericUserID).equals(userID)) {
    emitter.emit(Pair.of(numericUserID, userID));
  }
  if (!Long.toString(numericItemID).equals(itemID)) {
    emitter.emit(Pair.of(numericItemID, itemID));
  }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(String line, Emitter<Pair<Long, NumericIDValue>> emitter) {
  String[] columns = DelimitedDataUtils.decode(line);

  long userID = StringLongMapping.toLong(columns[0]);
  long itemID = StringLongMapping.toLong(columns[1]);

  float pref;
  if (columns.length > 2) {
    String valueToken = columns[2];
    pref = valueToken.isEmpty() ? Float.NaN : LangUtils.parseFloat(valueToken);
  } else {
    pref = 1.0f;
  }

  emitter.emit(Pair.of(userID, new NumericIDValue(itemID, pref)));
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(Pair<K, Iterable<Pair<Double, T>>> input,
    Emitter<Pair<K, Pair<Double, T>>> emitter) {
  SortedMap<Double, T> reservoir = Maps.newTreeMap();
  for (Pair<Double, T> p : input.second()) {
    if (reservoir.size() < sampleSize) { 
      reservoir.put(p.first(), ptype.getDetachedValue(p.second()));        
    } else if (p.first() > reservoir.firstKey()) {
      reservoir.remove(reservoir.firstKey());
      reservoir.put(p.first(), ptype.getDetachedValue(p.second()));  
    }
  }
  for (Map.Entry<Double, T> e : reservoir.entrySet()) {
    emitter.emit(Pair.of(input.first(), Pair.of(e.getKey(), e.getValue())));
  }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(Record record,
    Emitter<Pair<Integer, Pair<Long, InternalStats>>> emitter) {
  for (int idx = 0; idx < record.getSpec().size(); idx++) {
    if (!ignoredColumns.contains(idx)) {
      InternalStats ss = stats.get(idx);
      if (ss == null) {
        ss = new InternalStats();
        stats.put(idx, ss);
      }
      if (categoricalColumns.contains(idx)) {
        ss.addCategorical(record.getAsString(idx));
      } else {
        ss.addNumeric(record.getAsDouble(idx));
      }
    }
  }
  count++;
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(
    Pair<Tuple3<String, Long, String>,
        Iterable<Pair<Long,
            Pair<Tuple3<String, Long, String>, SpecificRecord>>>> input,
    Emitter<Pair<Tuple3<String, Long, String>, SpecificRecord>> emitter) {
  for (Pair<Long,
      Pair<Tuple3<String, Long, String>, SpecificRecord>> pair : input.second()) {
    emitter.emit(pair.second());
  }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(
    VariantContextWritable input, Emitter<Pair<Variant, Collection<Genotype>>> emitter) {
  VariantContext bvc = input.get();
  List<org.bdgenomics.adam.models.VariantContext> avcList =
      JavaConversions.seqAsJavaList(vcc.convert(bvc));
  for (org.bdgenomics.adam.models.VariantContext avc : avcList) {
    Variant variant = avc.variant().variant();
    Collection<Genotype> genotypes = JavaConversions.asJavaCollection(avc.genotypes());
    emitter.emit(Pair.of(variant, genotypes));
  }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process (SAMRecordWritable input, Emitter <Pair<Long, Pair<Integer, SAMRecordWritable>>> emitter) {
    // emit each position this read overlaps

    SAMRecord record = input.get();
    Integer startPosition = record.getAlignmentStart();

    Long lastTask = null;
    if (!record.getReadUnmappedFlag() && startPosition != null) {
        for (int i = startPosition; i < startPosition + record.getReadBases().length; ++i) {
            Long nextTask = positionToTaskMapping.get(new Pair<String, Integer>(record.getReferenceName(), i));

            // If we haven't mapped this position to a task, do so evenly
            if (nextTask == null) {
                nextTask = record.getReferenceName().hashCode() + (long) (i / intervalSize);
            }

            if (nextTask != lastTask) {
                lastTask = nextTask;
                emitter.emit(
                        // emit contig, interval and record
                        new Pair<Long, Pair<Integer, SAMRecordWritable>>(
                                lastTask,
                                new Pair(input.get().getAlignmentStart(), input)
                ));
            }
            // Skip length of interval or to the last base
            i = Math.min(record.getAlignmentEnd(), i + intervalSize);
        }
    }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(
    Pair<String, Iterable<StandardEvent>> keyAndEvents,
    Emitter<Session> emitter) {
  final Iterator<StandardEvent> events = keyAndEvents.second().iterator();
  if (!events.hasNext()) {
    return;
  }

  // Initialize the values needed to create a session for this group
  final StandardEvent firstEvent = events.next();
  long startTime = firstEvent.getTimestamp();
  long endTime = firstEvent.getTimestamp();
  int numEvents = 1;

  // Inspect each event and keep track of start time, end time, and count
  while (events.hasNext()) {
    final StandardEvent event = events.next();
    startTime = Math.min(startTime, event.getTimestamp());
    endTime = Math.max(endTime, event.getTimestamp());
    numEvents += 1;
  }

  // Create a session. Use the first event for fields that do not change
  emitter.emit(Session.newBuilder()             // same on all events:
      .setUserId(firstEvent.getUserId())        // the user id (grouped by)
      .setSessionId(firstEvent.getSessionId())  // session id (grouped by)
      .setIp(firstEvent.getIp())                // the source IP address
      .setStartTimestamp(startTime)
      .setDuration(endTime - startTime)
      .setSessionEventCount(numEvents)
      .build());
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(Pair<Long, Pair<float[], LongSet>> input,
                    Emitter<Pair<Integer, Pair<Long, Pair<float[], LongSet>>>> emitter) {
  for (int i = 0; i < numReducers; i++) {
    emitter.emit(Pair.of(i, input));
  }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(Pair<Long, Iterable<NumericIDValue>> input, Emitter<String> emitter) {
  StringLongMapping mapping = idMapping.getIDMapping();
  Iterable<NumericIDValue> recs = TopN.selectTopN(input.second().iterator(), numRecs);
  String userID = mapping.toString(input.first());
  for (NumericIDValue rec : recs) {
    emitter.emit(DelimitedDataUtils.encode(userID,
                                           mapping.toString(rec.getID()),
                                           Float.toString(rec.getValue())));
  }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void process(Pair<Long, float[]> input, Emitter<String> emitter) {
  if (input.first() % convergenceSamplingModulus == 0) {
    String userID = input.first().toString();
    float[] xu = input.second();
    for (LongObjectMap.MapEntry<float[]> entry : yState.getY().entrySet()) {
      long itemID = entry.getKey();
      if (itemID % convergenceSamplingModulus == 0) {
        float estimate = (float) SimpleVectorMath.dot(xu, entry.getValue());
        emitter.emit(DelimitedDataUtils.encode(userID, itemID, estimate));
      }
    }
  }
}
 

import org.apache.crunch.Emitter; //导入依赖的package包/类
@Override
public void cleanup(Emitter<Pair<Long, NumericIDValue>> emitter) {
  if (previousUserPrefs != null) {
    Preconditions.checkNotNull(previousUserID);
    output(previousUserID, previousUserPrefs, null, null, emitter);
  }
  super.cleanup(emitter);
}