content: /*
   * 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.asterix.geo.aggregates;
  
  import java.io.ByteArrayInputStream;
  import java.io.DataInput;
  import java.io.DataInputStream;
  import java.io.IOException;
  
  import org.apache.asterix.dataflow.data.nontagged.serde.AGeometrySerializerDeserializer;
  import org.apache.asterix.formats.nontagged.SerializerDeserializerProvider;
  import org.apache.asterix.om.base.AGeometry;
  import org.apache.asterix.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.EnumDeserializer;
  import org.apache.asterix.runtime.aggregates.std.AbstractAggregateFunction;
  import org.apache.asterix.runtime.exceptions.UnsupportedItemTypeException;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
  import org.apache.hyracks.api.context.IEvaluatorContext;
  import org.apache.hyracks.api.dataflow.value.ISerializerDeserializer;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.api.exceptions.SourceLocation;
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.data.std.primitive.VoidPointable;
  import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  import org.locationtech.jts.geom.Coordinate;
  import org.locationtech.jts.geom.Geometry;
  import org.locationtech.jts.geom.GeometryFactory;
  
  /**
   * STUnion aggregates a set of objects into one object. If the input is a set of overlapping polygons, their union is
   * computed and returned as a multipolygon. Similarly, if the input is a set of points or linestring, a multipoint or
   * multilinestring is created. Is the result contains geometries of different types, e.g., points and linestring, the
   * output is a GeometryCollection.
   */
  public class STUnionAggregateFunction extends AbstractAggregateFunction {
      @SuppressWarnings("unchecked")
      private ISerializerDeserializer<AGeometry> geometrySerde =
              SerializerDeserializerProvider.INSTANCE.getSerializerDeserializer(BuiltinType.AGEOMETRY);
      private IPointable inputVal = new VoidPointable();
      private IScalarEvaluator eval;
      protected Geometry geometry;
      protected GeometryFactory geometryFactory;
  
      private ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
  
      public STUnionAggregateFunction(IScalarEvaluatorFactory[] args, IEvaluatorContext context, SourceLocation sourceLoc)
              throws HyracksDataException {
          super(sourceLoc);
          eval = args[0].createScalarEvaluator(context);
      }
  
      @Override
      public void init() throws HyracksDataException {
          // Initialize the resulting geometry with an empty point.
          geometryFactory = new GeometryFactory();
          geometry = geometryFactory.createPoint((Coordinate) null);
      }
  
      @Override
      public void step(IFrameTupleReference tuple) throws HyracksDataException {
          eval.evaluate(tuple, inputVal);
          byte[] data = inputVal.getByteArray();
          int offset = inputVal.getStartOffset();
          int len = inputVal.getLength();
          ATypeTag typeTag =
                  EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(inputVal.getByteArray()[inputVal.getStartOffset()]);
          // Ignore SYSTEM_NULL.
          if (typeTag == ATypeTag.NULL || typeTag == ATypeTag.MISSING) {
              processNull();
          } else if (typeTag == ATypeTag.GEOMETRY) {
              DataInput dataIn = new DataInputStream(new ByteArrayInputStream(data, offset + 1, len - 1));
              Geometry geometry1 = AGeometrySerializerDeserializer.INSTANCE.deserialize(dataIn).getGeometry();
              geometry = geometry.union(geometry1);
          }
      }
  
      @Override
      public void finish(IPointable resultPointable) throws HyracksDataException {
          resultStorage.reset();
          try {
              geometrySerde.serialize(new AGeometry(geometry), resultStorage.getDataOutput());
          } catch (IOException e) {
              throw HyracksDataException.create(e);
          }
          resultPointable.set(resultStorage);
      }
  
      @Override
      public void finishPartial(IPointable resultPointable) throws HyracksDataException {
          finish(resultPointable);
      }
  
      protected void processNull() throws UnsupportedItemTypeException {
          throw new UnsupportedItemTypeException(sourceLoc, BuiltinFunctions.ST_UNION,
                  ATypeTag.SERIALIZED_SYSTEM_NULL_TYPE_TAG);
      }
  }
  