org.javimmutable.collections.hash.map.MapMultiKeyLeafNode Maven / Gradle / Ivy

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// Burton Computer Corporation
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package org.javimmutable.collections.hash.map;

import org.javimmutable.collections.Func1;
import org.javimmutable.collections.Holder;
import org.javimmutable.collections.Holders;
import org.javimmutable.collections.JImmutableMap;
import org.javimmutable.collections.Proc2;
import org.javimmutable.collections.Proc2Throws;
import org.javimmutable.collections.Sum2;
import org.javimmutable.collections.Sum2Throws;
import org.javimmutable.collections.common.CollisionMap;
import org.javimmutable.collections.iterators.GenericIterator;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;

/**
 * HamtNode that stores only one value.  Any assign that would progress down the tree
 * below this node replaces it with a normal node instead.  These exist to shorten the
 * height of the overall tree structure when hashCodes are dispersed.
 */
@Immutable
public class MapMultiKeyLeafNode
    implements MapNode
{
    private final int hashCode;
    @Nonnull
    private final CollisionMap.Node value;

    MapMultiKeyLeafNode(int hashCode,
                        @Nonnull CollisionMap.Node value)
    {
        this.hashCode = hashCode;
        this.value = value;
    }

    static  MapNode createLeaf(@Nonnull CollisionMap collisionMap,
                                           int hashCode,
                                           @Nonnull CollisionMap.Node value)
    {
        if (collisionMap.size(value) == 1) {
            return new MapSingleKeyLeafNode<>(collisionMap, hashCode, value);
        } else {
            assert collisionMap.size(value) > 1;
            return new MapMultiKeyLeafNode<>(hashCode, value);
        }
    }

    @Override
    public boolean isLeaf()
    {
        return true;
    }

    @Override
    public int size(@Nonnull CollisionMap collisionMap)
    {
        return collisionMap.size(value);
    }

    @Override
    public Holder find(@Nonnull CollisionMap collisionMap,
                          int hashCode,
                          @Nonnull K hashKey)
    {
        if (hashCode == this.hashCode) {
            return collisionMap.findValue(value, hashKey);
        } else {
            return Holders.of();
        }
    }

    @Override
    public V getValueOr(@Nonnull CollisionMap collisionMap,
                        int hashCode,
                        @Nonnull K hashKey,
                        V defaultValue)
    {
        if (hashCode == this.hashCode) {
            return collisionMap.getValueOr(value, hashKey, defaultValue);
        } else {
            return defaultValue;
        }
    }

    @Nonnull
    @Override
    public MapNode assign(@Nonnull CollisionMap collisionMap,
                                int hashCode,
                                @Nonnull K hashKey,
                                @Nullable V value)
    {
        final int thisHashCode = this.hashCode;
        final CollisionMap.Node thisValue = this.value;
        if (hashCode == thisHashCode) {
            final CollisionMap.Node newValue = collisionMap.update(thisValue, hashKey, value);
            if (newValue == thisValue) {
                return this;
            } else {
                return new MapMultiKeyLeafNode<>(hashCode, newValue);
            }
        } else {
            final MapNode expanded = MapBranchNode.forLeafExpansion(collisionMap, thisHashCode, thisValue);
            return expanded.assign(collisionMap, hashCode, hashKey, value);
        }
    }

    @Nonnull
    @Override
    public MapNode update(@Nonnull CollisionMap collisionMap,
                                int hashCode,
                                @Nonnull K hashKey,
                                @Nonnull Func1, V> generator)
    {
        final int thisHashCode = this.hashCode;
        final CollisionMap.Node thisValue = this.value;
        if (hashCode == thisHashCode) {
            final CollisionMap.Node newValue = collisionMap.update(value, hashKey, generator);
            if (newValue == thisValue) {
                return this;
            } else {
                return new MapMultiKeyLeafNode<>(hashCode, newValue);
            }
        } else {
            final MapNode expanded = MapBranchNode.forLeafExpansion(collisionMap, thisHashCode, thisValue);
            return expanded.update(collisionMap, hashCode, hashKey, generator);
        }
    }

    @Nonnull
    @Override
    public MapNode delete(@Nonnull CollisionMap collisionMap,
                                int hashCode,
                                @Nonnull K hashKey)
    {
        final int thisHashCode = this.hashCode;
        final CollisionMap.Node thisValue = this.value;
        if (hashCode == thisHashCode) {
            final CollisionMap.Node newValue = collisionMap.delete(thisValue, hashKey);
            if (newValue == thisValue) {
                return this;
            } else {
                final int newSize = collisionMap.size(newValue);
                if (newSize == 0) {
                    return MapEmptyNode.of();
                } else if (newSize == 1) {
                    return new MapSingleKeyLeafNode<>(collisionMap, hashCode, newValue);
                } else {
                    return new MapMultiKeyLeafNode<>(hashCode, newValue);
                }
            }
        } else {
            return this;
        }
    }

    @Override
    @Nonnull
    public MapNode liftNode(int index)
    {
        return new MapMultiKeyLeafNode<>(hashCode << MapBranchNode.SHIFT | index, value);
    }

    @Override
    public boolean isEmpty(@Nonnull CollisionMap collisionMap)
    {
        return collisionMap.size(value) == 0;
    }

    @Nullable
    @Override
    public GenericIterator.State> iterateOverRange(@Nonnull CollisionMap collisionMap,
                                                                             @Nullable GenericIterator.State> parent,
                                                                             int offset,
                                                                             int limit)
    {
        return collisionMap.iterateOverRange(value, parent, offset, limit);
    }

    @Override
    public void forEach(@Nonnull CollisionMap collisionMap,
                        @Nonnull Proc2 proc)
    {
        collisionMap.forEach(value, proc);
    }

    @Override
    public  void forEachThrows(@Nonnull CollisionMap collisionMap,
                                                    @Nonnull Proc2Throws proc)
        throws E
    {
        collisionMap.forEachThrows(value, proc);
    }

    @Override
    public  R reduce(@Nonnull CollisionMap collisionMap,
                        R sum,
                        @Nonnull Sum2 proc)
    {
        return collisionMap.reduce(value, sum, proc);
    }

    @Override
    public  R reduceThrows(@Nonnull CollisionMap collisionMap,
                                                   R sum,
                                                   @Nonnull Sum2Throws proc)
        throws E
    {
        return collisionMap.reduceThrows(value, sum, proc);
    }

    @Override
    public void checkInvariants(@Nonnull CollisionMap collisionMap)
    {
        if (collisionMap.size(value) < 2) {
            throw new IllegalStateException(String.format("expected size greater than one: size=%d", collisionMap.size(value)));
        }
    }

    @Override
    public String toString()
    {
        final StringBuilder sb = new StringBuilder();
        sb.append("(0x");
        sb.append(Integer.toHexString(hashCode));
        sb.append(",");
        sb.append(value);
        sb.append(")");
        return sb.toString();
    }
}