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

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/*
 * Copyright (c) 2018-2021, Antonio Gabriel Muñoz Conejo 
 * Distributed under the terms of the MIT License
 */
package com.github.tonivade.purefun.data;

import static java.util.Collections.unmodifiableNavigableSet;
import static java.util.stream.Collectors.collectingAndThen;

import java.io.Serializable;
import java.util.Arrays;
import java.util.Iterator;
import java.util.NavigableSet;
import java.util.Objects;
import java.util.TreeSet;
import java.util.stream.Collector;
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.Kind;
import com.github.tonivade.purefun.Matcher1;
import com.github.tonivade.purefun.type.Option;
import com.github.tonivade.purefun.type.Try;

public interface ImmutableTree extends Sequence {

  NavigableSet toNavigableSet();

  @Override
  ImmutableTree append(E element);
  @Override
  ImmutableTree remove(E element);
  @Override
  ImmutableTree appendAll(Sequence other);
  @Override
  ImmutableTree removeAll(Sequence other);

  @Override
  ImmutableTree reverse();

  Option head();
  Option tail();
  ImmutableTree headTree(E value);
  ImmutableTree tailTree(E value);
  Option higher(E value);
  Option lower(E value);
  Option ceiling(E value);
  Option floor(E value);

  @Override
  default  ImmutableTree map(Function1 mapper) {
    return ImmutableTree.from(stream().map(mapper::apply));
  }

  @Override
  default  ImmutableTree flatMap(Function1> mapper) {
    return ImmutableTree.from(stream().flatMap(mapper.andThen(SequenceOf::narrowK).andThen(Sequence::stream)::apply));
  }

  @Override
  default ImmutableTree filter(Matcher1 matcher) {
    return ImmutableTree.from(stream().filter(matcher::match));
  }

  @Override
  default ImmutableTree filterNot(Matcher1 matcher) {
    return filter(matcher.negate());
  }

  static  ImmutableTree from(Iterable iterable) {
    return from(Sequence.asStream(iterable.iterator()));
  }

  static  ImmutableTree from(Stream stream) {
    return new JavaBasedImmutableTree<>(stream.collect(Collectors.toCollection(TreeSet::new)));
  }

  @SafeVarargs
  static  ImmutableTree of(T... elements) {
    return new JavaBasedImmutableTree<>(new TreeSet<>(Arrays.asList(elements)));
  }

  @SuppressWarnings("unchecked")
  static  ImmutableTree empty() {
    return (ImmutableTree) JavaBasedImmutableTree.EMPTY;
  }

  static  Collector> toImmutableTree() {
    return collectingAndThen(Collectors.toCollection(TreeSet::new), JavaBasedImmutableTree::new);
  }

  final class JavaBasedImmutableTree implements ImmutableTree, Serializable {

    private static final long serialVersionUID = -328223831102407507L;
    
    private static final ImmutableTree EMPTY = new JavaBasedImmutableTree<>(new TreeSet<>());

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

    private final NavigableSet backend;

    private JavaBasedImmutableTree(TreeSet backend) {
      this.backend = unmodifiableNavigableSet(backend);
    }

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

    @Override
    public boolean contains(E element) {
      return backend.contains(element);
    }

    @Override
    public ImmutableTree reverse() {
      return this;
    }

    @Override
    public ImmutableTree append(E element) {
      TreeSet newSet = copy();
      newSet.add(element);
      return new JavaBasedImmutableTree<>(newSet);
    }

    @Override
    public ImmutableTree remove(E element) {
      TreeSet newSet = copy();
      newSet.remove(element);
      return new JavaBasedImmutableTree<>(newSet);
    }

    @Override
    public ImmutableTree appendAll(Sequence other) {
      TreeSet newSet = copy();
      newSet.addAll(other.toCollection());
      return new JavaBasedImmutableTree<>(newSet);
    }

    @Override
    public ImmutableTree removeAll(Sequence other) {
      TreeSet newSet = copy();
      newSet.removeAll(other.toCollection());
      return new JavaBasedImmutableTree<>(newSet);
    }

    @Override
    public Option head() {
      return Try.of(backend::first).toOption();
    }

    @Override
    public Option tail() {
      return Try.of(backend::last).toOption();
    }

    @Override
    public ImmutableTree headTree(E toElement) {
      return new JavaBasedImmutableTree<>(new TreeSet<>(backend.headSet(toElement, false)));
    }

    @Override
    public ImmutableTree tailTree(E fromElement) {
      return new JavaBasedImmutableTree<>(new TreeSet<>(backend.tailSet(fromElement, false)));
    }

    @Override
    public Option higher(E value) {
      return Option.of(() -> backend.higher(value));
    }

    @Override
    public Option lower(E value) {
      return Option.of(() -> backend.lower(value));
    }

    @Override
    public Option ceiling(E value) {
      return Option.of(() -> backend.ceiling(value));
    }

    @Override
    public Option floor(E value) {
      return Option.of(() -> backend.floor(value));
    }

    @Override
    public Iterator iterator() {
      return backend.iterator();
    }

    @Override
    public NavigableSet toNavigableSet() {
      return new TreeSet<>(backend);
    }

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

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

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

    private TreeSet copy() {
      return new TreeSet<>(backend);
    }
  }
}