com.github.tonivade.purefun.data.ImmutableTreeMap Maven / Gradle / Ivy

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/*
 * Copyright (c) 2018-2020, Antonio Gabriel Muñoz Conejo 
 * Distributed under the terms of the MIT License
 */
package com.github.tonivade.purefun.data;

import static java.util.Collections.unmodifiableNavigableMap;
import static java.util.Collections.emptyNavigableMap;

import java.io.Serializable;
import java.util.Map;
import java.util.NavigableMap;
import java.util.Objects;
import java.util.TreeMap;
import java.util.function.BinaryOperator;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import com.github.tonivade.purefun.Equal;
import com.github.tonivade.purefun.Function1;
import com.github.tonivade.purefun.Matcher1;
import com.github.tonivade.purefun.Operator2;
import com.github.tonivade.purefun.Producer;
import com.github.tonivade.purefun.Tuple;
import com.github.tonivade.purefun.Tuple2;
import com.github.tonivade.purefun.type.Option;
import com.github.tonivade.purefun.type.Try;

public interface ImmutableTreeMap extends ImmutableMap {

  NavigableMap toNavigableMap();

  @Override
  ImmutableTreeMap put(K key, V value);

  @Override
  default ImmutableTreeMap putAll(ImmutableSet> other) {
    return ImmutableTreeMap.from(entries().appendAll(other));
  }

  @Override
  ImmutableTreeMap remove(K key);

  @Override
  ImmutableTreeMap merge(K key, V value, Operator2 merger);

  ImmutableTreeMap headMap(K toKey);
  ImmutableTreeMap tailMap(K fromKey);
  Option> headEntry();
  Option> tailEntry();
  Option> higherEntry(K key);
  Option> lowerEntry(K key);
  Option> floorEntry(K key);
  Option> ceilingEntry(K key);

  default Option headKey() {
    return headEntry().map(Tuple2::get1);
  }

  default Option tailKey() {
    return tailEntry().map(Tuple2::get1);
  }

  default Option higherKey(K key) {
    return higherEntry(key).map(Tuple2::get1);
  }

  default Option lowerKey(K key) {
    return lowerEntry(key).map(Tuple2::get1);
  }

  default Option floorKey(K key) {
    return floorEntry(key).map(Tuple2::get1);
  }

  default Option ceilingKey(K key) {
    return floorEntry(key).map(Tuple2::get1);
  }

  @Override
  default  ImmutableTreeMap map(Function1 keyMapper, Function1 valueMapper) {
    return ImmutableTreeMap.from(entries().map(tuple -> tuple.map(keyMapper, valueMapper)));
  }

  @Override
  default  ImmutableTreeMap mapKeys(Function1 mapper) {
    return ImmutableTreeMap.from(entries().map(tuple -> tuple.map1(mapper)));
  }

  @Override
  default  ImmutableTreeMap mapValues(Function1 mapper) {
    return ImmutableTreeMap.from(entries().map(tuple -> tuple.map2(mapper)));
  }

  @Override
  default ImmutableTreeMap filterKeys(Matcher1 filter) {
    return ImmutableTreeMap.from(entries().filter(tuple -> filter.match(tuple.get1())));
  }

  @Override
  default ImmutableTreeMap filterValues(Matcher1 filter) {
    return ImmutableTreeMap.from(entries().filter(tuple -> filter.match(tuple.get2())));
  }

  @Override
  default ImmutableTreeMap putIfAbsent(K key, V value) {
    if (containsKey(key)) {
      return this;
    }
    return put(key, value);
  }

  @Override
  default V getOrDefault(K key, Producer supplier) {
    return get(key).getOrElse(supplier);
  }

  @Override
  default boolean isEmpty() {
    return size() == 0;
  }

  @SafeVarargs
  static  ImmutableTreeMap of(Tuple2... entries) {
    return from(ImmutableSet.of(entries));
  }

  static  Tuple2 entry(K key, V value) {
    return Tuple2.of(key, value);
  }

  static  ImmutableTreeMap from(NavigableMap map) {
    return new JavaBasedImmutableTreeMap<>(map);
  }

  static  ImmutableTreeMap empty() {
    return new JavaBasedImmutableTreeMap<>(emptyNavigableMap());
  }

  static  ImmutableTreeMap from(Stream> entries) {
    return from(ImmutableSet.from(entries));
  }

  static  ImmutableTreeMap from(ImmutableSet> entries) {
    return new JavaBasedImmutableTreeMap<>(entries.stream()
        .collect(Collectors.toMap(Tuple2::get1, Tuple2::get2, ImmutableTreeModule.throwingMerge(), TreeMap::new)));
  }

  static , V> Builder builder() {
    return new Builder<>();
  }

  final class Builder, V> {

    private final NavigableMap map = new TreeMap<>();

    private Builder() { }

    public Builder put(K key, V value) {
      map.put(key, value);
      return this;
    }

    public ImmutableTreeMap build() {
      return ImmutableTreeMap.from(map);
    }
  }

  final class JavaBasedImmutableTreeMap implements ImmutableTreeMap, Serializable {

    private static final long serialVersionUID = 8618845296089216532L;

    private static final Equal> EQUAL = 
        Equal.>of().comparing(a -> a.backend);

    private final NavigableMap backend;

    private JavaBasedImmutableTreeMap(NavigableMap backend) {
      this.backend = unmodifiableNavigableMap(backend);
    }

    @Override
    public Map toMap() {
      return toNavigableMap();
    }

    @Override
    public NavigableMap toNavigableMap() {
      return new TreeMap<>(backend);
    }

    @Override
    public ImmutableTreeMap put(K key, V value) {
      NavigableMap newMap = toNavigableMap();
      newMap.put(key, value);
      return new JavaBasedImmutableTreeMap<>(newMap);
    }

    @Override
    public ImmutableTreeMap remove(K key) {
      NavigableMap newMap = toNavigableMap();
      newMap.remove(key);
      return new JavaBasedImmutableTreeMap<>(newMap);
    }

    @Override
    public Option get(K key) {
      return Option.of(() -> backend.get(key));
    }

    @Override
    public ImmutableTreeMap merge(K key, V value, Operator2 merger) {
      NavigableMap newMap = toNavigableMap();
      newMap.merge(key, value, merger::apply);
      return new JavaBasedImmutableTreeMap<>(newMap);
    }

    @Override
    public ImmutableTreeMap headMap(K toKey) {
      return new JavaBasedImmutableTreeMap<>(backend.headMap(toKey, false));
    }

    @Override
    public ImmutableTreeMap tailMap(K fromKey) {
      return new JavaBasedImmutableTreeMap<>(backend.tailMap(fromKey, false));
    }

    @Override
    public Option> headEntry() {
      return Try.of(() -> Tuple.from(backend.firstEntry())).toOption();
    }

    @Override
    public Option> tailEntry() {
      return Try.of(() -> Tuple.from(backend.lastEntry())).toOption();
    }

    @Override
    public Option> higherEntry(K key) {
      return Try.of(() -> Tuple.from(backend.higherEntry(key))).toOption();
    }

    @Override
    public Option> lowerEntry(K key) {
      return Try.of(() -> Tuple.from(backend.lowerEntry(key))).toOption();
    }

    @Override
    public Option> floorEntry(K key) {
      return Try.of(() -> Tuple.from(backend.floorEntry(key))).toOption();
    }

    @Override
    public Option> ceilingEntry(K key) {
      return Try.of(() -> Tuple.from(backend.ceilingEntry(key))).toOption();
    }

    @Override
    public Sequence values() {
      return ImmutableList.from(backend.values());
    }

    @Override
    public ImmutableSet keys() {
      return ImmutableSet.from(backend.keySet());
    }

    @Override
    public ImmutableSet> entries() {
      return ImmutableSet.from(backend.entrySet()).map(Tuple::from);
    }

    @Override
    public int size() {
      return backend.size();
    }

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

    @Override
    public boolean equals(Object obj) {
      return EQUAL.applyTo(this, obj);
    }

    @Override
    public String toString() {
      return "ImmutableTreeMap(" + backend + ")";
    }
  }
}

interface ImmutableTreeModule {

  static  BinaryOperator throwingMerge() {
    return (a, b) -> { throw new IllegalArgumentException("conflict detected"); };
  }
}