Code/net/minecraft/server/dedicated/Settings.java

package net.minecraft.server.dedicated;

import com.google.common.base.MoreObjects;
import com.mojang.logging.LogUtils;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.Writer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CodingErrorAction;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Objects;
import java.util.Properties;
import java.util.function.Function;
import java.util.function.IntFunction;
import java.util.function.Supplier;
import java.util.function.UnaryOperator;
import javax.annotation.Nullable;
import net.minecraft.core.RegistryAccess;
import org.slf4j.Logger;

public abstract class Settings<T extends Settings<T>> {
    private static final Logger LOGGER = LogUtils.getLogger();
    protected final Properties properties;

    public Settings(Properties p_139801_) {
        this.properties = p_139801_;
    }

    public static Properties loadFromFile(Path p_139840_) {
        try {
            try {
                Properties properties3;
                try (InputStream inputstream = Files.newInputStream(p_139840_)) {
                    CharsetDecoder charsetdecoder = StandardCharsets.UTF_8
                        .newDecoder()
                        .onMalformedInput(CodingErrorAction.REPORT)
                        .onUnmappableCharacter(CodingErrorAction.REPORT);
                    Properties properties2 = new Properties();
                    properties2.load(new InputStreamReader(inputstream, charsetdecoder));
                    properties3 = properties2;
                }

                return properties3;
            } catch (CharacterCodingException charactercodingexception) {
                LOGGER.info("Failed to load properties as UTF-8 from file {}, trying ISO_8859_1", p_139840_);

                Properties properties1;
                try (Reader reader = Files.newBufferedReader(p_139840_, StandardCharsets.ISO_8859_1)) {
                    Properties properties = new Properties();
                    properties.load(reader);
                    properties1 = properties;
                }

                return properties1;
            }
        } catch (IOException ioexception) {
            LOGGER.error("Failed to load properties from file: {}", p_139840_, ioexception);
            return new Properties();
        }
    }

    public void store(Path p_139877_) {
        try (Writer writer = Files.newBufferedWriter(p_139877_, StandardCharsets.UTF_8)) {
            this.properties.store(writer, "Minecraft server properties");
        } catch (IOException ioexception) {
            LOGGER.error("Failed to store properties to file: {}", p_139877_);
        }
    }

    private static <V extends Number> Function<String, V> wrapNumberDeserializer(Function<String, V> p_139842_) {
        return p_139845_ -> {
            try {
                return p_139842_.apply(p_139845_);
            } catch (NumberFormatException numberformatexception) {
                return null;
            }
        };
    }

    protected static <V> Function<String, V> dispatchNumberOrString(IntFunction<V> p_139851_, Function<String, V> p_139852_) {
        return p_139856_ -> {
            try {
                return p_139851_.apply(Integer.parseInt(p_139856_));
            } catch (NumberFormatException numberformatexception) {
                return p_139852_.apply(p_139856_);
            }
        };
    }

    @Nullable
    private String getStringRaw(String p_139879_) {
        return (String)this.properties.get(p_139879_);
    }

    @Nullable
    protected <V> V getLegacy(String p_139815_, Function<String, V> p_139816_) {
        String s = this.getStringRaw(p_139815_);
        if (s == null) {
            return null;
        } else {
            this.properties.remove(p_139815_);
            return p_139816_.apply(s);
        }
    }

    protected <V> V get(String p_139822_, Function<String, V> p_139823_, Function<V, String> p_139824_, V p_139825_) {
        String s = this.getStringRaw(p_139822_);
        V v = MoreObjects.firstNonNull(s != null ? p_139823_.apply(s) : null, p_139825_);
        this.properties.put(p_139822_, p_139824_.apply(v));
        return v;
    }

    protected <V> Settings<T>.MutableValue<V> getMutable(String p_139869_, Function<String, V> p_139870_, Function<V, String> p_139871_, V p_139872_) {
        String s = this.getStringRaw(p_139869_);
        V v = MoreObjects.firstNonNull(s != null ? p_139870_.apply(s) : null, p_139872_);
        this.properties.put(p_139869_, p_139871_.apply(v));
        return new MutableValue<>(p_139869_, v, p_139871_);
    }

    protected <V> V get(String p_139827_, Function<String, V> p_139828_, UnaryOperator<V> p_139829_, Function<V, String> p_139830_, V p_139831_) {
        return this.get(p_139827_, p_139849_ -> {
            V v = p_139828_.apply(p_139849_);
            return v != null ? p_139829_.apply(v) : null;
        }, p_139830_, p_139831_);
    }

    protected <V> V get(String p_139818_, Function<String, V> p_139819_, V p_139820_) {
        return this.get(p_139818_, p_139819_, Objects::toString, p_139820_);
    }

    protected <V> Settings<T>.MutableValue<V> getMutable(String p_139865_, Function<String, V> p_139866_, V p_139867_) {
        return this.getMutable(p_139865_, p_139866_, Objects::toString, p_139867_);
    }

    protected String get(String p_139812_, String p_139813_) {
        return this.get(p_139812_, Function.identity(), Function.identity(), p_139813_);
    }

    @Nullable
    protected String getLegacyString(String p_139804_) {
        return this.getLegacy(p_139804_, Function.identity());
    }

    protected int get(String p_139806_, int p_139807_) {
        return this.get(p_139806_, wrapNumberDeserializer(Integer::parseInt), p_139807_);
    }

    protected Settings<T>.MutableValue<Integer> getMutable(String p_139862_, int p_139863_) {
        return this.getMutable(p_139862_, wrapNumberDeserializer(Integer::parseInt), p_139863_);
    }

    protected int get(String p_139833_, UnaryOperator<Integer> p_139834_, int p_139835_) {
        return this.get(p_139833_, wrapNumberDeserializer(Integer::parseInt), p_139834_, Objects::toString, p_139835_);
    }

    protected long get(String p_139809_, long p_139810_) {
        return this.get(p_139809_, wrapNumberDeserializer(Long::parseLong), p_139810_);
    }

    protected boolean get(String p_139837_, boolean p_139838_) {
        return this.get(p_139837_, Boolean::valueOf, p_139838_);
    }

    protected Settings<T>.MutableValue<Boolean> getMutable(String p_139874_, boolean p_139875_) {
        return this.getMutable(p_139874_, Boolean::valueOf, p_139875_);
    }

    @Nullable
    protected Boolean getLegacyBoolean(String p_139860_) {
        return this.getLegacy(p_139860_, Boolean::valueOf);
    }

    protected Properties cloneProperties() {
        Properties properties = new Properties();
        properties.putAll(this.properties);
        return properties;
    }

    protected abstract T reload(RegistryAccess p_139857_, Properties p_139858_);

    public class MutableValue<V> implements Supplier<V> {
        private final String key;
        private final V value;
        private final Function<V, String> serializer;

        MutableValue(final String p_139886_, final V p_139887_, final Function<V, String> p_139888_) {
            this.key = p_139886_;
            this.value = p_139887_;
            this.serializer = p_139888_;
        }

        @Override
        public V get() {
            return this.value;
        }

        public T update(RegistryAccess p_139896_, V p_139897_) {
            Properties properties = Settings.this.cloneProperties();
            properties.put(this.key, this.serializer.apply(p_139897_));
            return Settings.this.reload(p_139896_, properties);
        }
    }
}