Code/net/minecraft/world/level/block/state/StateHolder.java

package net.minecraft.world.level.block.state;

import com.mojang.serialization.Codec;
import com.mojang.serialization.MapCodec;
import it.unimi.dsi.fastutil.objects.Reference2ObjectArrayMap;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Map.Entry;
import java.util.function.Function;
import java.util.stream.Collectors;
import javax.annotation.Nullable;
import net.minecraft.world.level.block.state.properties.Property;

public abstract class StateHolder<O, S> {
    public static final String NAME_TAG = "Name";
    public static final String PROPERTIES_TAG = "Properties";
    private static final Function<Entry<Property<?>, Comparable<?>>, String> PROPERTY_ENTRY_TO_STRING_FUNCTION = new Function<Entry<Property<?>, Comparable<?>>, String>() {
        public String apply(@Nullable Entry<Property<?>, Comparable<?>> p_61155_) {
            if (p_61155_ == null) {
                return "<NULL>";
            } else {
                Property<?> property = p_61155_.getKey();
                return property.getName() + "=" + this.getName(property, p_61155_.getValue());
            }
        }

        private <T extends Comparable<T>> String getName(Property<T> p_61152_, Comparable<?> p_61153_) {
            return p_61152_.getName((T)p_61153_);
        }
    };
    protected final O owner;
    private final Reference2ObjectArrayMap<Property<?>, Comparable<?>> values;
    private Map<Property<?>, S[]> neighbours;
    protected final MapCodec<S> propertiesCodec;

    protected StateHolder(O p_61117_, Reference2ObjectArrayMap<Property<?>, Comparable<?>> p_331170_, MapCodec<S> p_61119_) {
        this.owner = p_61117_;
        this.values = p_331170_;
        this.propertiesCodec = p_61119_;
    }

    public <T extends Comparable<T>> S cycle(Property<T> p_61123_) {
        return this.setValue(p_61123_, findNextInCollection(p_61123_.getPossibleValues(), this.getValue(p_61123_)));
    }

    protected static <T> T findNextInCollection(List<T> p_366325_, T p_61132_) {
        int i = p_366325_.indexOf(p_61132_) + 1;
        return i == p_366325_.size() ? p_366325_.getFirst() : p_366325_.get(i);
    }

    @Override
    public String toString() {
        StringBuilder stringbuilder = new StringBuilder();
        stringbuilder.append(this.owner);
        if (!this.getValues().isEmpty()) {
            stringbuilder.append('[');
            stringbuilder.append(this.getValues().entrySet().stream().map(PROPERTY_ENTRY_TO_STRING_FUNCTION).collect(Collectors.joining(",")));
            stringbuilder.append(']');
        }

        return stringbuilder.toString();
    }

    @Override
    public final boolean equals(Object p_397228_) {
        return super.equals(p_397228_);
    }

    @Override
    public int hashCode() {
        return super.hashCode();
    }

    public Collection<Property<?>> getProperties() {
        return Collections.unmodifiableCollection(this.values.keySet());
    }

    public boolean hasProperty(Property<?> p_61139_) {
        return this.values.containsKey(p_61139_);
    }

    public <T extends Comparable<T>> T getValue(Property<T> p_61144_) {
        Comparable<?> comparable = this.values.get(p_61144_);
        if (comparable == null) {
            throw new IllegalArgumentException("Cannot get property " + p_61144_ + " as it does not exist in " + this.owner);
        } else {
            return p_61144_.getValueClass().cast(comparable);
        }
    }

    public <T extends Comparable<T>> Optional<T> getOptionalValue(Property<T> p_61146_) {
        return Optional.ofNullable(this.getNullableValue(p_61146_));
    }

    public <T extends Comparable<T>> T getValueOrElse(Property<T> p_364529_, T p_364048_) {
        return Objects.requireNonNullElse(this.getNullableValue(p_364529_), p_364048_);
    }

    @Nullable
    private <T extends Comparable<T>> T getNullableValue(Property<T> p_361815_) {
        Comparable<?> comparable = this.values.get(p_361815_);
        return comparable == null ? null : p_361815_.getValueClass().cast(comparable);
    }

    public <T extends Comparable<T>, V extends T> S setValue(Property<T> p_61125_, V p_61126_) {
        Comparable<?> comparable = this.values.get(p_61125_);
        if (comparable == null) {
            throw new IllegalArgumentException("Cannot set property " + p_61125_ + " as it does not exist in " + this.owner);
        } else {
            return this.setValueInternal(p_61125_, p_61126_, comparable);
        }
    }

    public <T extends Comparable<T>, V extends T> S trySetValue(Property<T> p_263324_, V p_263334_) {
        Comparable<?> comparable = this.values.get(p_263324_);
        return (S)(comparable == null ? this : this.setValueInternal(p_263324_, p_263334_, comparable));
    }

    private <T extends Comparable<T>, V extends T> S setValueInternal(Property<T> p_361946_, V p_367503_, Comparable<?> p_369806_) {
        if (p_369806_.equals(p_367503_)) {
            return (S)this;
        } else {
            int i = p_361946_.getInternalIndex((T)p_367503_);
            if (i < 0) {
                throw new IllegalArgumentException(
                    "Cannot set property " + p_361946_ + " to " + p_367503_ + " on " + this.owner + ", it is not an allowed value"
                );
            } else {
                return (S)this.neighbours.get(p_361946_)[i];
            }
        }
    }

    public void populateNeighbours(Map<Map<Property<?>, Comparable<?>>, S> p_61134_) {
        if (this.neighbours != null) {
            throw new IllegalStateException();
        } else {
            Map<Property<?>, S[]> map = new Reference2ObjectArrayMap<>(this.values.size());

            for (Entry<Property<?>, Comparable<?>> entry : this.values.entrySet()) {
                Property<?> property = entry.getKey();
                map.put(property, (S[])property.getPossibleValues().stream().map(p_360554_ -> p_61134_.get(this.makeNeighbourValues(property, p_360554_))).toArray());
            }

            this.neighbours = map;
        }
    }

    private Map<Property<?>, Comparable<?>> makeNeighbourValues(Property<?> p_61141_, Comparable<?> p_61142_) {
        Map<Property<?>, Comparable<?>> map = new Reference2ObjectArrayMap<>(this.values);
        map.put(p_61141_, p_61142_);
        return map;
    }

    public Map<Property<?>, Comparable<?>> getValues() {
        return this.values;
    }

    protected static <O, S extends StateHolder<O, S>> Codec<S> codec(Codec<O> p_61128_, Function<O, S> p_61129_) {
        return p_61128_.dispatch(
            "Name",
            p_61121_ -> p_61121_.owner,
            p_327407_ -> {
                S s = p_61129_.apply((O)p_327407_);
                return s.getValues().isEmpty()
                    ? MapCodec.unit(s)
                    : s.propertiesCodec.codec().lenientOptionalFieldOf("Properties").xmap(p_187544_ -> p_187544_.orElse(s), Optional::of);
            }
        );
    }
}