/*
* Druid - a distributed column store.
* Copyright (C) 2012, 2013 Metamarkets Group Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package io.druid.query.select;
import com.google.common.base.Function;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.metamx.common.ISE;
import com.metamx.common.guava.Sequence;
import io.druid.query.QueryRunnerHelper;
import io.druid.query.Result;
import io.druid.segment.Cursor;
import io.druid.segment.DimensionSelector;
import io.druid.segment.LongColumnSelector;
import io.druid.segment.ObjectColumnSelector;
import io.druid.segment.Segment;
import io.druid.segment.StorageAdapter;
import io.druid.segment.column.Column;
import io.druid.segment.data.IndexedInts;
import io.druid.segment.filter.Filters;
import org.joda.time.DateTime;
import java.util.List;
import java.util.Map;
/**
*/
public class SelectQueryEngine
{
public Sequence<Result<SelectResultValue>> process(final SelectQuery query, final Segment segment)
{
final StorageAdapter adapter = segment.asStorageAdapter();
if (adapter == null) {
throw new ISE(
"Null storage adapter found. Probably trying to issue a query against a segment being memory unmapped."
);
}
final Iterable<String> dims;
if (query.getDimensions() == null || query.getDimensions().isEmpty()) {
dims = adapter.getAvailableDimensions();
} else {
dims = query.getDimensions();
}
final Iterable<String> metrics;
if (query.getMetrics() == null || query.getMetrics().isEmpty()) {
metrics = adapter.getAvailableMetrics();
} else {
metrics = query.getMetrics();
}
return QueryRunnerHelper.makeCursorBasedQuery(
adapter,
query.getQuerySegmentSpec().getIntervals(),
Filters.convertDimensionFilters(query.getDimensionsFilter()),
query.getGranularity(),
new Function<Cursor, Result<SelectResultValue>>()
{
@Override
public Result<SelectResultValue> apply(Cursor cursor)
{
final SelectResultValueBuilder builder = new SelectResultValueBuilder(
cursor.getTime(),
query.getPagingSpec()
.getThreshold()
);
final LongColumnSelector timestampColumnSelector = cursor.makeLongColumnSelector(Column.TIME_COLUMN_NAME);
final Map<String, DimensionSelector> dimSelectors = Maps.newHashMap();
for (String dim : dims) {
final DimensionSelector dimSelector = cursor.makeDimensionSelector(dim);
dimSelectors.put(dim, dimSelector);
}
final Map<String, ObjectColumnSelector> metSelectors = Maps.newHashMap();
for (String metric : metrics) {
final ObjectColumnSelector metricSelector = cursor.makeObjectColumnSelector(metric);
metSelectors.put(metric, metricSelector);
}
int startOffset;
if (query.getPagingSpec().getPagingIdentifiers() == null) {
startOffset = 0;
} else {
Integer offset = query.getPagingSpec().getPagingIdentifiers().get(segment.getIdentifier());
startOffset = (offset == null) ? 0 : offset;
}
cursor.advanceTo(startOffset);
int offset = 0;
while (!cursor.isDone() && offset < query.getPagingSpec().getThreshold()) {
final Map<String, Object> theEvent = Maps.newLinkedHashMap();
theEvent.put(EventHolder.timestampKey, new DateTime(timestampColumnSelector.get()));
for (Map.Entry<String, DimensionSelector> dimSelector : dimSelectors.entrySet()) {
final String dim = dimSelector.getKey();
final DimensionSelector selector = dimSelector.getValue();
if (selector == null) {
theEvent.put(dim, null);
} else {
final IndexedInts vals = selector.getRow();
if (vals.size() == 1) {
final String dimVal = selector.lookupName(vals.get(0));
theEvent.put(dim, dimVal);
} else {
List<String> dimVals = Lists.newArrayList();
for (int i = 0; i < vals.size(); ++i) {
dimVals.add(selector.lookupName(vals.get(i)));
}
theEvent.put(dim, dimVals);
}
}
}
for (Map.Entry<String, ObjectColumnSelector> metSelector : metSelectors.entrySet()) {
final String metric = metSelector.getKey();
final ObjectColumnSelector selector = metSelector.getValue();
if (selector == null) {
theEvent.put(metric, null);
} else {
theEvent.put(metric, selector.get());
}
}
builder.addEntry(
new EventHolder(
segment.getIdentifier(),
startOffset + offset,
theEvent
)
);
cursor.advance();
offset++;
}
return builder.build();
}
}
);
}
}