org.javimmutable.collections.hash.set.SetSingleValueLeafNode Maven / Gradle / Ivy

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

import org.javimmutable.collections.Proc1;
import org.javimmutable.collections.Proc1Throws;
import org.javimmutable.collections.Sum1;
import org.javimmutable.collections.Sum1Throws;
import org.javimmutable.collections.common.CollisionSet;
import org.javimmutable.collections.iterators.GenericIterator;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
import java.util.Objects;

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

    SetSingleValueLeafNode(int hashCode,
                           @Nonnull T value)
    {
        this.hashCode = hashCode;
        this.value = value;
    }

    SetSingleValueLeafNode(@Nonnull CollisionSet collisionSet,
                           int hashCode,
                           @Nonnull CollisionSet.Node node)
    {
        assert collisionSet.size(node) == 1;
        this.hashCode = hashCode;
        this.value = collisionSet.iterator(node).next();
    }

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

    @Override
    public int size(@Nonnull CollisionSet collisionSet)
    {
        return 1;
    }

    @Override
    public boolean contains(@Nonnull CollisionSet collisionSet,
                            int hashCode,
                            @Nonnull T value)
    {
        return this.hashCode == hashCode && this.value.equals(value);
    }

    @Nonnull
    @Override
    public SetNode insert(@Nonnull CollisionSet collisionSet,
                             int hashCode,
                             @Nonnull T value)
    {
        final int thisHashCode = this.hashCode;
        final T thisValue = this.value;
        if (thisHashCode == hashCode) {
            if (thisValue.equals(value)) {
                return this;
            } else {
                final CollisionSet.Node thisNode = collisionSet.single(thisValue);
                return new SetMultiValueLeafNode<>(hashCode, collisionSet.insert(thisNode, value));
            }
        } else {
            final SetNode expanded = SetBranchNode.forLeafExpansion(collisionSet, thisHashCode, thisValue);
            return expanded.insert(collisionSet, hashCode, value);
        }
    }

    @Nonnull
    @Override
    public SetNode delete(@Nonnull CollisionSet collisionSet,
                             int hashCode,
                             @Nonnull T value)
    {
        if (this.hashCode == hashCode && this.value.equals(value)) {
            return SetEmptyNode.of();
        } else {
            return this;
        }
    }

    @Nonnull
    public SetNode liftNode(int index)
    {
        return new SetSingleValueLeafNode<>(hashCode << SetBranchNode.SHIFT | index, value);
    }

    @Override
    public boolean isEmpty(@Nonnull CollisionSet collisionSet)
    {
        return false;
    }

    @Nullable
    @Override
    public GenericIterator.State iterateOverRange(@Nonnull CollisionSet collisionSet,
                                                     @Nullable GenericIterator.State parent,
                                                     int offset,
                                                     int limit)
    {
        return GenericIterator.valueState(parent, value);
    }

    @Override
    public void forEach(@Nonnull CollisionSet collisionSet,
                        @Nonnull Proc1 proc)
    {
        proc.apply(value);
    }

    @Override
    public  void forEachThrows(@Nonnull CollisionSet collisionSet,
                                                    @Nonnull Proc1Throws proc)
        throws E
    {
        proc.apply(value);
    }

    @Override
    public  R reduce(@Nonnull CollisionSet collisionSet,
                        R sum,
                        @Nonnull Sum1 proc)
    {
        return proc.apply(sum, value);
    }

    @Override
    public  R reduceThrows(@Nonnull CollisionSet collisionSet,
                                                   R sum,
                                                   @Nonnull Sum1Throws proc)
        throws E
    {
        return proc.apply(sum, value);
    }

    @Override
    public boolean equals(Object o)
    {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        SetSingleValueLeafNode that = (SetSingleValueLeafNode)o;
        return hashCode == that.hashCode &&
               value.equals(that.value);
    }

    @Override
    public int hashCode()
    {
        return Objects.hash(hashCode, value);
    }

    @Override
    public String toString()
    {
        return "(0x" + Integer.toHexString(hashCode) + "," + value + ")";
    }
}