| /* |
| * 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.druid.query.aggregation; |
| |
| import org.apache.druid.guice.annotations.PublicApi; |
| import org.apache.druid.segment.BaseNullableColumnValueSelector; |
| import org.apache.druid.segment.ColumnSelectorFactory; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * Null-aware numeric {@link Aggregator}. |
| * |
| * The result of this aggregator will be null if all the values to be aggregated are null values or no values are |
| * aggregated at all. If any of the values are non-null, the result will be the aggregated value of the delegate |
| * aggregator. |
| * |
| * When wrapped by this class, the underlying aggregator's required storage space is increased by one byte. The extra |
| * byte is a boolean that stores whether or not any non-null values have been seen. The extra byte is placed before |
| * the underlying aggregator's normal state. (Buffer layout = [nullability byte] [delegate storage bytes]) |
| * |
| * Used by {@link NullableNumericAggregatorFactory#factorize(ColumnSelectorFactory)} to wrap non-null aware |
| * aggregators. This class is only used when SQL compatible null handling is enabled. |
| * |
| * @see NullableNumericAggregatorFactory#factorize(ColumnSelectorFactory) |
| */ |
| @PublicApi |
| public final class NullableNumericAggregator implements Aggregator |
| { |
| private final Aggregator delegate; |
| private final BaseNullableColumnValueSelector selector; |
| private boolean isNullResult = true; |
| |
| public NullableNumericAggregator(Aggregator delegate, BaseNullableColumnValueSelector selector) |
| { |
| this.delegate = delegate; |
| this.selector = selector; |
| } |
| |
| @Override |
| public void aggregate() |
| { |
| boolean isNotNull = !selector.isNull(); |
| if (isNotNull) { |
| if (isNullResult) { |
| isNullResult = false; |
| } |
| delegate.aggregate(); |
| } |
| } |
| |
| @Override |
| @Nullable |
| public Object get() |
| { |
| if (isNullResult) { |
| return null; |
| } |
| return delegate.get(); |
| } |
| |
| @Override |
| public float getFloat() |
| { |
| if (isNullResult) { |
| throw new IllegalStateException("Cannot return float for Null Value"); |
| } |
| return delegate.getFloat(); |
| } |
| |
| @Override |
| public long getLong() |
| { |
| if (isNullResult) { |
| throw new IllegalStateException("Cannot return long for Null Value"); |
| } |
| return delegate.getLong(); |
| } |
| |
| @Override |
| public double getDouble() |
| { |
| if (isNullResult) { |
| throw new IllegalStateException("Cannot return double for Null Value"); |
| } |
| return delegate.getDouble(); |
| } |
| |
| @Override |
| public boolean isNull() |
| { |
| return isNullResult || delegate.isNull(); |
| } |
| |
| @Override |
| public void close() |
| { |
| delegate.close(); |
| } |
| } |