asterixdb/asterix-runtime/src/main/java/org/apache/asterix/runtime/evaluators/functions/CreatePolygonDescriptor.java

/*
 * 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.runtime.evaluators.functions;

import java.io.DataOutput;
import java.io.IOException;

import org.apache.asterix.common.exceptions.AsterixException;
import org.apache.asterix.dataflow.data.nontagged.serde.ADoubleSerializerDeserializer;
import org.apache.asterix.dataflow.data.nontagged.serde.APointSerializerDeserializer;
import org.apache.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
import org.apache.asterix.om.base.ANull;
import org.apache.asterix.om.functions.AsterixBuiltinFunctions;
import org.apache.asterix.om.functions.IFunctionDescriptor;
import org.apache.asterix.om.functions.IFunctionDescriptorFactory;
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.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
import org.apache.asterix.runtime.evaluators.common.AsterixListAccessor;
import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
import org.apache.hyracks.api.context.IHyracksTaskContext;
import org.apache.hyracks.api.dataflow.value.ISerializerDeserializer;
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;

public class CreatePolygonDescriptor extends AbstractScalarFunctionDynamicDescriptor {

    private static final long serialVersionUID = 1L;
    public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
        @Override
        public IFunctionDescriptor createFunctionDescriptor() {
            return new CreatePolygonDescriptor();
        }
    };

    @Override
    public IScalarEvaluatorFactory createEvaluatorFactory(final IScalarEvaluatorFactory[] args) {
        return new IScalarEvaluatorFactory() {

            private static final long serialVersionUID = 1L;

            @Override
            public IScalarEvaluator createScalarEvaluator(IHyracksTaskContext ctx) throws AlgebricksException {
                return new IScalarEvaluator() {

                    private final AsterixListAccessor listAccessor = new AsterixListAccessor();
                    private final ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
                    private final DataOutput out = resultStorage.getDataOutput();
                    private final IScalarEvaluatorFactory listEvalFactory = args[0];
                    private final IPointable inputArgList = new VoidPointable();
                    private final IScalarEvaluator evalList = listEvalFactory.createScalarEvaluator(ctx);
                    @SuppressWarnings("unchecked")
                    private final ISerializerDeserializer<ANull> nullSerde = AqlSerializerDeserializerProvider.INSTANCE
                            .getSerializerDeserializer(BuiltinType.ANULL);

                    @Override
                    public void evaluate(IFrameTupleReference tuple, IPointable result) throws AlgebricksException {
                        try {
                            resultStorage.reset();
                            evalList.evaluate(tuple, inputArgList);
                            byte[] listBytes = inputArgList.getByteArray();
                            int offset = inputArgList.getStartOffset();

                            if (listBytes[offset] != ATypeTag.SERIALIZED_ORDEREDLIST_TYPE_TAG) {
                                throw new AlgebricksException(AsterixBuiltinFunctions.CREATE_POLYGON.getName()
                                        + ": expects input type ORDEREDLIST, but got "
                                        + EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(listBytes[offset]));
                            }
                            try {
                                listAccessor.reset(listBytes, offset);
                            } catch (AsterixException e) {
                                throw new AlgebricksException(e);
                            }
                            try {
                                // First check the list consists of a valid items
                                for (int i = 0; i < listAccessor.size(); i++) {
                                    int itemOffset = listAccessor.getItemOffset(i);
                                    ATypeTag itemType = listAccessor.getItemType(itemOffset);
                                    if (itemType != ATypeTag.DOUBLE) {
                                        if (itemType == ATypeTag.NULL) {
                                            nullSerde.serialize(ANull.NULL, out);
                                            return;
                                        }
                                        throw new AlgebricksException(AsterixBuiltinFunctions.CREATE_POLYGON.getName()
                                                + ": expects type DOUBLE/NULL for the list item but got " + itemType);
                                    }

                                }
                                if (listAccessor.size() < 6) {
                                    throw new AlgebricksException(
                                            "A polygon instance must consists of at least 3 points");
                                } else if (listAccessor.size() % 2 != 0) {
                                    throw new AlgebricksException(
                                            "There must be an even number of double values in the list to form a polygon");
                                }
                                out.writeByte(ATypeTag.SERIALIZED_POLYGON_TYPE_TAG);
                                out.writeShort(listAccessor.size() / 2);

                                for (int i = 0; i < listAccessor.size() / 2; i++) {
                                    int firstDoubleOffset = listAccessor.getItemOffset(i * 2);
                                    int secondDobuleOffset = listAccessor.getItemOffset((i * 2) + 1);

                                    APointSerializerDeserializer.serialize(
                                            ADoubleSerializerDeserializer.getDouble(listBytes, firstDoubleOffset),
                                            ADoubleSerializerDeserializer.getDouble(listBytes, secondDobuleOffset),
                                            out);
                                }
                                result.set(resultStorage);
                            } catch (AsterixException ex) {
                                throw new AlgebricksException(ex);
                            }
                        } catch (IOException e1) {
                            throw new AlgebricksException(e1.getMessage());
                        }
                    }
                };
            }
        };
    }

    @Override
    public FunctionIdentifier getIdentifier() {
        return AsterixBuiltinFunctions.CREATE_POLYGON;
    }
}