Java tutorial
/* * Licensed to Metamarkets Group Inc. (Metamarkets) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. Metamarkets 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 io.druid.query.aggregation.hyperloglog; import io.druid.data.input.InputRow; import io.druid.hll.HyperLogLogCollector; import io.druid.hll.HyperLogLogHash; import io.druid.java.util.common.ISE; import io.druid.segment.serde.ComplexMetricExtractor; import org.apache.commons.codec.binary.Base64; import java.nio.ByteBuffer; public class PreComputedHyperUniquesSerde extends HyperUniquesSerde { public PreComputedHyperUniquesSerde(HyperLogLogHash hyperLogLogHash) { super(hyperLogLogHash); } @Override public ComplexMetricExtractor getExtractor() { return new ComplexMetricExtractor() { @Override public Class<HyperLogLogCollector> extractedClass() { return HyperLogLogCollector.class; } @Override public HyperLogLogCollector extractValue(InputRow inputRow, String metricName) { Object rawValue = inputRow.getRaw(metricName); if (rawValue == null) { return HyperLogLogCollector.makeLatestCollector(); } else if (rawValue instanceof HyperLogLogCollector) { return (HyperLogLogCollector) rawValue; } else if (rawValue instanceof byte[]) { return HyperLogLogCollector.makeLatestCollector().fold(ByteBuffer.wrap((byte[]) rawValue)); } else if (rawValue instanceof String) { return HyperLogLogCollector.makeLatestCollector() .fold(ByteBuffer.wrap(Base64.decodeBase64((String) rawValue))); } throw new ISE("Object is not of a type[%s] that can be deserialized to HyperLogLog.", rawValue.getClass()); } }; } }