Issue58.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;

import net.openhft.chronicle.bytes.Bytes;
import net.openhft.chronicle.hash.serialization.BytesReader;
import net.openhft.chronicle.hash.serialization.BytesWriter;
import net.openhft.chronicle.hash.serialization.impl.EnumMarshallable;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

import static java.util.stream.Collectors.toMap;

public class Issue58 {
    File mapFile = new File("string-to-uuid.dat");
    File reverseMapFile = new File("uuid-to-string.dat");

    public static void main(String... args) {
        Map<String, UUID> map = new HashMap<>();
        map.put("AA", UUID.randomUUID());
        map.put("AB", UUID.randomUUID());
        map.put("BA", UUID.randomUUID());
        map.put("BB", UUID.randomUUID());
        try {
            Issue58 test = new Issue58();
            test.writeMapAndReverseMap(map);
            test.test1(map);
            test.test2(map);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void writeMapAndReverseMap(Map<String, UUID> data) throws IOException {
        if (mapFile.exists())
            mapFile.delete();
        if (reverseMapFile.exists())
            reverseMapFile.delete();

        try (
                ChronicleMap<String, UUID> map = ChronicleMap.of(String.class, UUID.class)
                        .averageKeySize(2)
                        .valueMarshaller(UuidMarshaller.INSTANCE)
                        .constantValueSizeBySample(UUID.randomUUID())
                        .entries(data.size())
                        .createPersistedTo(mapFile);
                ChronicleMap<UUID, String> reverseMap = ChronicleMap.of(UUID.class, String.class)
                        .keyMarshaller(UuidMarshaller.INSTANCE)
                        .averageValueSize(2)
                        .constantKeySizeBySample(UUID.randomUUID())
                        .entries(data.size())
                        .createPersistedTo(reverseMapFile)
        ) {

            map.putAll(data);
            Map<UUID, String> reverse = data.keySet().stream()
                    .collect(toMap(k -> data.get(k), k -> k));
            reverseMap.putAll(reverse);
        }
}

    public void test1(Map<String, UUID> data) throws IOException {
        try (
                ChronicleMap<String, UUID> map = ChronicleMap.of(String.class, UUID.class)
                        .averageKeySize(2)
                        .valueMarshaller(UuidMarshaller.INSTANCE)
                        .constantValueSizeBySample(UUID.randomUUID())
                        .entries(data.size())
                        .createPersistedTo(mapFile);
                ChronicleMap<UUID, String> reverseMap = ChronicleMap.of(UUID.class, String.class)
                        .keyMarshaller(UuidMarshaller.INSTANCE)
                        .constantKeySizeBySample(UUID.randomUUID())
                        .averageValueSize(2)
                        .entries(data.size())
                        .createPersistedTo(reverseMapFile)
        ) {
            System.out.println("first test passes:");
            UUID uuid = data.get("BB");
            System.out.println("BB" + " == " + reverseMap.get(uuid));
            System.out.println(uuid + " == " + map.get("BB"));
        }
    }

    public void test2(Map<String, UUID> data) throws IOException {
        try (
                ChronicleMap<String, UUID> map = ChronicleMap.of(String.class, UUID.class)
                        .averageKeySize(2)
                        .valueMarshaller(UuidMarshaller.INSTANCE)
                        .constantValueSizeBySample(UUID.randomUUID())
                        .entries(data.size())
                        .createPersistedTo(mapFile);
                ChronicleMap<UUID, String> reverseMap = ChronicleMap.of(UUID.class, String.class)
                        .keyMarshaller(UuidMarshaller.INSTANCE)
                        .constantKeySizeBySample(UUID.randomUUID())
                        .averageValueSize(2)
                        .entries(data.size())
                        .createPersistedTo(reverseMapFile)
        ) {
            System.out.println("second identical test also passes:");
            UUID uuid = data.get("BB");
            System.out.println("BB" + " == " + reverseMap.get(uuid));
            System.out.println(uuid + " == " + map.get("BB")); //returns null
            System.out.println("despite all data being present:");
            map.entrySet().forEach(e -> System.out.println(e.getKey() + "->" + e.getValue()));
            reverseMap.forEach((k, v) -> System.out.println(k + " -> " + v));
        }
}

    static final class UuidMarshaller
            implements BytesReader<UUID>, BytesWriter<UUID>, EnumMarshallable<UuidMarshaller> {
        public static final UuidMarshaller INSTANCE = new UuidMarshaller();

        private UuidMarshaller() {}

        @Override
        public void write(Bytes bytes, @NotNull UUID uuid) {
            bytes.writeLong(uuid.getMostSignificantBits());
            bytes.writeLong(uuid.getLeastSignificantBits());
        }

        @NotNull
        @Override
        public UUID read(Bytes bytes, @Nullable UUID using) {
            return new UUID(bytes.readLong(), bytes.readLong());
        }

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