org.openstreetmap.atlas.proto.adapters.ProtoLongToLongMapAdapter Maven / Gradle / Ivy

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package org.openstreetmap.atlas.proto.adapters;

import org.openstreetmap.atlas.exception.CoreException;
import org.openstreetmap.atlas.proto.ProtoLongArray;
import org.openstreetmap.atlas.proto.ProtoLongToLongMap;
import org.openstreetmap.atlas.proto.ProtoSerializable;
import org.openstreetmap.atlas.utilities.maps.LongToLongMap;

import com.google.protobuf.InvalidProtocolBufferException;

/**
 * Implements the {@link ProtoAdapter} interface to connect {@link LongToLongMap} and
 * {@link ProtoLongToLongMap}.
 *
 * @author lcram
 */
public class ProtoLongToLongMapAdapter implements ProtoAdapter
{
    /*
     * If the maximum size of the LongToLongMap we are reading is less than this value, just use
     * this value instead of the actual max size. This ensures that calculations in LargeMap using
     * DEFAULT_HASH_MODULO_RATIO do not fail do to integer division truncation.
     */
    private static final int DEFAULT_MAX_SIZE = 1024;

    @Override
    public ProtoSerializable deserialize(final byte[] byteArray)
    {
        ProtoLongToLongMap protoLongToLongMap = null;
        try
        {
            protoLongToLongMap = ProtoLongToLongMap.parseFrom(byteArray);
        }
        catch (final InvalidProtocolBufferException exception)
        {
            throw new CoreException("Error encountered while parsing protobuf bytestream",
                    exception);
        }

        String deserializedName = null;
        if (protoLongToLongMap.hasName())
        {
            deserializedName = protoLongToLongMap.getName();
        }

        final int size = protoLongToLongMap.getKeys().getElementsCount() <= DEFAULT_MAX_SIZE
                ? DEFAULT_MAX_SIZE
                : protoLongToLongMap.getKeys().getElementsCount();
        final LongToLongMap longToLongMap = new LongToLongMap(deserializedName, size, size, size,
                size, size, size);

        for (int index = 0; index < protoLongToLongMap.getKeys().getElementsCount(); index++)
        {
            longToLongMap.put(protoLongToLongMap.getKeys().getElements(index),
                    protoLongToLongMap.getValues().getElements(index));
        }

        return longToLongMap;
    }

    @Override
    public byte[] serialize(final ProtoSerializable serializable)
    {
        if (!(serializable instanceof LongToLongMap))
        {
            throw new CoreException(
                    "Invalid ProtoSerializable type was provided to {}: cannot serialize {}",
                    this.getClass().getName(), serializable.getClass().getName());
        }
        final LongToLongMap longMap = (LongToLongMap) serializable;

        if (longMap.size() > Integer.MAX_VALUE)
        {
            throw new CoreException("Cannot serialize {}, size too large ({})",
                    longMap.getClass().getName(), longMap.size());
        }

        final ProtoLongToLongMap.Builder protoMapBuilder = ProtoLongToLongMap.newBuilder();
        final ProtoLongArray.Builder keysBuilder = ProtoLongArray.newBuilder();
        final ProtoLongArray.Builder valuesBuilder = ProtoLongArray.newBuilder();

        final Iterable iterable = () -> longMap.iterator();
        for (final Long key : iterable)
        {
            final Long value = longMap.get(key);
            keysBuilder.addElements(key);
            valuesBuilder.addElements(value);
        }
        protoMapBuilder.setKeys(keysBuilder);
        protoMapBuilder.setValues(valuesBuilder);
        if (longMap.getName() != null)
        {
            protoMapBuilder.setName(longMap.getName());
        }

        return protoMapBuilder.build().toByteArray();
    }
}