| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.phoenix.iterate; |
| |
| import static org.apache.phoenix.query.QueryConstants.AGG_TIMESTAMP; |
| import static org.apache.phoenix.query.QueryConstants.SINGLE_COLUMN; |
| import static org.apache.phoenix.query.QueryConstants.SINGLE_COLUMN_FAMILY; |
| |
| import java.sql.SQLException; |
| import java.util.List; |
| |
| import org.apache.hadoop.hbase.KeyValue; |
| import org.apache.hadoop.hbase.io.ImmutableBytesWritable; |
| import org.apache.phoenix.expression.aggregator.Aggregator; |
| import org.apache.phoenix.expression.aggregator.Aggregators; |
| import org.apache.phoenix.schema.tuple.Tuple; |
| import org.apache.phoenix.util.KeyValueUtil; |
| |
| /** |
| * |
| * Base class for result scanners that aggregate the row count value for rows with |
| * duplicate keys. This result scanner assumes that the results of the inner result |
| * scanner are returned in order of grouping keys. |
| * |
| */ |
| public abstract class BaseGroupedAggregatingResultIterator implements |
| AggregatingResultIterator { |
| private static final byte[] UNITIALIZED_KEY_BUFFER = new byte[0]; |
| protected final PeekingResultIterator resultIterator; |
| protected final Aggregators aggregators; |
| private ImmutableBytesWritable currentKey; |
| private ImmutableBytesWritable nextKey; |
| |
| public BaseGroupedAggregatingResultIterator( |
| PeekingResultIterator resultIterator, Aggregators aggregators) { |
| if (resultIterator == null) throw new NullPointerException(); |
| if (aggregators == null) throw new NullPointerException(); |
| this.resultIterator = resultIterator; |
| this.aggregators = aggregators; |
| this.currentKey = new ImmutableBytesWritable(UNITIALIZED_KEY_BUFFER); |
| this.nextKey = new ImmutableBytesWritable(UNITIALIZED_KEY_BUFFER); |
| } |
| |
| protected abstract ImmutableBytesWritable getGroupingKey(Tuple tuple, ImmutableBytesWritable ptr) throws SQLException; |
| protected abstract Tuple wrapKeyValueAsResult(KeyValue keyValue) throws SQLException; |
| |
| @Override |
| public Tuple next() throws SQLException { |
| Tuple result = resultIterator.next(); |
| if (result == null) { |
| return null; |
| } |
| if (currentKey.get() == UNITIALIZED_KEY_BUFFER) { |
| getGroupingKey(result, currentKey); |
| } |
| Aggregator[] rowAggregators = aggregators.getAggregators(); |
| aggregators.reset(rowAggregators); |
| while (true) { |
| aggregators.aggregate(rowAggregators, result); |
| Tuple nextResult = resultIterator.peek(); |
| if (nextResult == null || !currentKey.equals(getGroupingKey(nextResult, nextKey))) { |
| break; |
| } |
| result = resultIterator.next(); |
| } |
| |
| byte[] value = aggregators.toBytes(rowAggregators); |
| Tuple tuple = wrapKeyValueAsResult(KeyValueUtil.newKeyValue(currentKey, SINGLE_COLUMN_FAMILY, SINGLE_COLUMN, AGG_TIMESTAMP, value, 0, value.length)); |
| currentKey.set(nextKey.get(), nextKey.getOffset(), nextKey.getLength()); |
| return tuple; |
| } |
| |
| @Override |
| public void close() throws SQLException { |
| resultIterator.close(); |
| } |
| |
| @Override |
| public Aggregator[] aggregate(Tuple result) { |
| Aggregator[] rowAggregators = aggregators.getAggregators(); |
| aggregators.reset(rowAggregators); |
| aggregators.aggregate(rowAggregators, result); |
| return rowAggregators; |
| } |
| |
| @Override |
| public void explain(List<String> planSteps) { |
| resultIterator.explain(planSteps); |
| } |
| |
| } |