edu.mit.streamjit.impl.compiler2.MapConcreteStorage.java Source code

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/*
 * Copyright (c) 2013-2015 Massachusetts Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package edu.mit.streamjit.impl.compiler2;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.collect.Maps;
import edu.mit.streamjit.util.bytecode.methodhandles.Combinators;
import static edu.mit.streamjit.util.bytecode.methodhandles.LookupUtils.findVirtual;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * A ConcreteStorage implementation using a Map<Integer, T>.
 * @author Jeffrey Bosboom <jbosboom@csail.mit.edu>
 * @since 10/27/2013
 */
public final class MapConcreteStorage implements ConcreteStorage {
    private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
    private static final MethodHandle MAP_GET = findVirtual(Map.class, "get")
            .asType(MethodType.methodType(Object.class, Map.class, int.class));
    private static final MethodHandle MAP_PUT = findVirtual(Map.class, "put")
            .asType(MethodType.methodType(void.class, Map.class, int.class, Object.class));
    private static final MethodHandle ADJUST = findVirtual(LOOKUP, "adjust");
    private final Class<?> type;
    private final Map<Integer, Object> map = new ConcurrentHashMap<>();
    private final MethodHandle readHandle, writeHandle, adjustHandle;
    private final int minReadIndex, throughput;

    private MapConcreteStorage(Class<?> type, MethodHandle adjustHandle, int minReadIndex, int throughput) {
        this.type = type;
        this.readHandle = MAP_GET.bindTo(map).asType(MethodType.methodType(type, int.class));
        this.writeHandle = MAP_PUT.bindTo(map).asType(MethodType.methodType(void.class, int.class, type));
        this.adjustHandle = adjustHandle.bindTo(this);
        this.minReadIndex = minReadIndex;
        this.throughput = throughput;
    }

    public static MapConcreteStorage create(Storage s) {
        ImmutableSet<ActorGroup> relevantGroups = ImmutableSet.<ActorGroup>builder().addAll(s.upstreamGroups())
                .addAll(s.downstreamGroups()).build();
        return new MapConcreteStorage(s.type(), ADJUST, s.readIndices(Maps.asMap(relevantGroups, i -> 1)).first(),
                s.throughput());
    }

    public static MapConcreteStorage createNopAdjust(Storage s) {
        return new MapConcreteStorage(s.type(), Combinators.nop(Object.class), Integer.MAX_VALUE,
                Integer.MAX_VALUE);
    }
    //TODO: create(Storage s, Map<ActorGroup, Integer> schedule) if we want adjusting

    @Override
    public Class<?> type() {
        return type;
    }

    @Override
    public void adjust() {
        //This is pretty slow, but we need them in order so we don't overwrite.
        ImmutableSortedSet<Integer> indices = ImmutableSortedSet.copyOf(map.keySet());
        for (int i : indices) {
            int newReadIndex = i - throughput;
            Object item = map.remove(i);
            if (newReadIndex >= minReadIndex) {
                Object overwrote = map.put(newReadIndex, item);
                assert overwrote == null : newReadIndex;
            }
        }
    }

    @Override
    public void sync() {
    }

    @Override
    public MethodHandle readHandle() {
        return readHandle;
    }

    @Override
    public MethodHandle writeHandle() {
        return writeHandle;
    }

    @Override
    public MethodHandle adjustHandle() {
        return adjustHandle;
    }

    @Override
    public String toString() {
        return map.toString();
    }

    public static StorageFactory factory() {
        return MapConcreteStorage::create;
    }

    public static StorageFactory initFactory() {
        return MapConcreteStorage::createNopAdjust;
    }
}