PointListSizedMarshaller.java

/*
 *      Copyright (C) 2012, 2016  higherfrequencytrading.com
 *      Copyright (C) 2016 Roman Leventov
 *
 *      This program is free software: you can redistribute it and/or modify
 *      it under the terms of the GNU Lesser General Public License as published by
 *      the Free Software Foundation, either version 3 of the License.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU Lesser General Public License for more details.
 *
 *      You should have received a copy of the GNU Lesser General Public License
 *      along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.openhft.chronicle.map.fromdocs;

import net.openhft.chronicle.bytes.Bytes;
import net.openhft.chronicle.core.io.IORuntimeException;
import net.openhft.chronicle.core.util.ReadResolvable;
import net.openhft.chronicle.hash.serialization.SizedReader;
import net.openhft.chronicle.hash.serialization.SizedWriter;
import net.openhft.chronicle.wire.WireIn;
import net.openhft.chronicle.wire.WireOut;
import org.jetbrains.annotations.NotNull;

import java.util.ArrayList;
import java.util.List;

public final class PointListSizedMarshaller
        implements SizedReader<List<Point>>, SizedWriter<List<Point>>,
        ReadResolvable<PointListSizedMarshaller> {

    static final PointListSizedMarshaller INSTANCE = new PointListSizedMarshaller();

    private PointListSizedMarshaller() {}

    /** A point takes 16 bytes in serialized form: 8 bytes for both x and y value */
    private static final long ELEMENT_SIZE = 16;

    @Override
    public long size(@NotNull List<Point> toWrite) {
        return toWrite.size() * ELEMENT_SIZE;
    }

    @Override
    public void write(Bytes out, long size, @NotNull List<Point> toWrite) {
        toWrite.forEach(point -> {
            out.writeDouble(point.x);
            out.writeDouble(point.y);
        });
    }

    @NotNull
    @Override
    public List<Point> read(@NotNull Bytes in, long size, List<Point> using) {
        if (size % ELEMENT_SIZE != 0) {
            throw new IORuntimeException("Bytes size should be a multiple of " + ELEMENT_SIZE +
                    ", " + size + " read");
        }
        long listSizeAsLong = size / ELEMENT_SIZE;
        if (listSizeAsLong > Integer.MAX_VALUE) {
            throw new IORuntimeException("List size couldn't be more than " + Integer.MAX_VALUE +
                    ", " + listSizeAsLong + " read");
        }
        int listSize = (int) listSizeAsLong;
        if (using == null) {
            using = new ArrayList<>(listSize);
            for (int i = 0; i < listSize; i++) {
                using.add(null);
            }
        } else if (using.size() < listSize) {
            while (using.size() < listSize) {
                using.add(null);
            }
        } else if (using.size() > listSize) {
            using.subList(listSize, using.size()).clear();
        }
        for (int i = 0; i < listSize; i++) {
            Point point = using.get(i);
            if (point == null)
                using.set(i, point = new Point());
            point.x = in.readDouble();
            point.y = in.readDouble();
        }
        return using;
    }

    @Override
    public void writeMarshallable(@NotNull WireOut wireOut) {
        // no fields to write
    }

    @Override
    public void readMarshallable(@NotNull WireIn wireIn) {
        // no fields to read
    }

    @Override
    public PointListSizedMarshaller readResolve() {
        return INSTANCE;
    }
}