Update custom collections with new functionality

deck-of-cards-kata/src/main/java/bnymellon/codekatas/deckofcards/custom/collections/ImmutableCollection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 The Bank of New York Mellon.
+ * Copyright 2023 The Bank of New York Mellon.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -44,7 +44,11 @@ default ImmutableCollection<T> peek(Consumer<? super T> consumer)
  default <K> ImmutableBag<K> countBy(Function<? super T, ? extends K> function)
  {
  var counts = MutableBag.<K>empty();
- this.forEach(each -> counts.add(function.apply(each)));
- return counts.toImmutable();
+ return this.map(function, counts).toImmutable();
+ }
+
+ default <V> ImmutableBag<V> countByEach(Function<? super T, ? extends Iterable<V>> function)
+ {
+ return this.flatMap(function, MutableBag.empty()).toImmutable();
  }
 }

deck-of-cards-kata/src/main/java/bnymellon/codekatas/deckofcards/custom/collections/MutableBag.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 The Bank of New York Mellon.
+ * Copyright 2023 The Bank of New York Mellon.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -79,44 +79,27 @@ default MutableBag<T> peek(Consumer<? super T> consumer)
  default MutableBag<T> filter(Predicate<? super T> predicate)
  {
  var mutableBag = MutableBag.<T>empty();
- for (T each : this)
- {
- if (predicate.test(each))
- {
- mutableBag.add(each);
- }
- }
- return mutableBag;
+ return this.filter(predicate, mutableBag);
  }
 
  @Override
  default MutableBag<T> filterNot(Predicate<? super T> predicate)
  {
- var mutableBag = MutableBag.<T>empty();
- for (T each : this)
- {
- if (!predicate.test(each))
- {
- mutableBag.add(each);
- }
- }
- return mutableBag;
+ return this.filter(predicate.negate());
  }
 
  @Override
  default <V> MutableBag<V> map(Function<? super T, ? extends V> function)
  {
  var mutableBag = MutableBag.<V>empty();
- this.forEach(each -> mutableBag.add(function.apply(each)));
- return mutableBag;
+ return this.map(function, mutableBag);
  }
 
  @Override
  default <V> MutableBag<V> flatMap(Function<? super T, ? extends Iterable<V>> function)
  {
  var mutableBag = MutableBag.<V>empty();
- this.forEach(each -> mutableBag.addAllIterable(function.apply(each)));
- return mutableBag;
+ return this.flatMap(function, mutableBag);
  }
 
  default <K> ArrayListMultimap<K, T> groupBy(Function<? super T, ? extends K> function)

deck-of-cards-kata/src/main/java/bnymellon/codekatas/deckofcards/custom/collections/MutableCollection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 The Bank of New York Mellon.
+ * Copyright 2023 The Bank of New York Mellon.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,15 +29,12 @@ default boolean addAllIterable(Iterable<T> iterable)
  {
  return this.addAll(collection);
  }
- else
+ boolean result = false;
+ for (T each : iterable)
  {
- boolean result = false;
- for (T each : iterable)
- {
- result |= this.add(each);
- }
- return result;
+ result |= this.add(each);
  }
+ return result;
  }
 
  @Override
@@ -71,4 +68,9 @@ default <K> MutableBag<K> countBy(Function<? super T, ? extends K> function)
  this.forEach(each -> counts.add(function.apply(each)));
  return counts;
  }
+
+ default <V> MutableBag<V> countByEach(Function<? super T, ? extends Iterable<V>> function)
+ {
+ return this.flatMap(function, MutableBag.empty());
+ }
 }

deck-of-cards-kata/src/main/java/bnymellon/codekatas/deckofcards/custom/collections/MutableList.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 The Bank of New York Mellon.
+ * Copyright 2023 The Bank of New York Mellon.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -81,44 +81,27 @@ default MutableList<T> asUnmodifiable()
  default MutableList<T> filter(Predicate<? super T> predicate)
  {
  var mutableList = MutableList.<T>empty();
- for (T each : this)
- {
- if (predicate.test(each))
- {
- mutableList.add(each);
- }
- }
- return mutableList;
+ return this.filter(predicate, mutableList);
  }
 
  @Override
  default MutableList<T> filterNot(Predicate<? super T> predicate)
  {
- var mutableList = MutableList.<T>empty();
- for (T each : this)
- {
- if (!predicate.test(each))
- {
- mutableList.add(each);
- }
- }
- return mutableList;
+ return this.filter(predicate.negate());
  }
 
  @Override
  default <V> MutableList<V> map(Function<? super T, ? extends V> function)
  {
  var mutableList = MutableList.<V>empty();
- this.forEach(each -> mutableList.add(function.apply(each)));
- return mutableList;
+ return this.map(function, mutableList);
  }
 
  @Override
  default <V> MutableList<V> flatMap(Function<? super T, ? extends Iterable<V>> function)
  {
  var mutableList = MutableList.<V>empty();
- this.forEach(each -> mutableList.addAllIterable(function.apply(each)));
- return mutableList;
+ return this.flatMap(function, mutableList);
  }
 
  @Override
@@ -135,6 +118,13 @@ default <K> MutableListMultimap<K, T> groupBy(Function<? super T, ? extends K> f
  return multimap;
  }
 
+ default <K> MutableListMultimap<K, T> groupByEach(Function<? super T, ? extends Iterable<K>> function)
+ {
+ var multimap = MutableListMultimap.<K, T>empty();
+ this.forEach(each -> function.apply(each).forEach(key -> multimap.put(key, each)));
+ return multimap;
+ }
+
  default <K> MutableListMultimap<K, T> groupByUnmodifiable(Function<? super T, ? extends K> function)
  {
  var multimap = this.<K>groupBy(function);

deck-of-cards-kata/src/main/java/bnymellon/codekatas/deckofcards/custom/collections/MutableSet.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 The Bank of New York Mellon.
+ * Copyright 2023 The Bank of New York Mellon.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -78,44 +78,27 @@ default java.util.Set<T> asUnmodifiable()
  default MutableSet<T> filter(Predicate<? super T> predicate)
  {
  var mutableSet = MutableSet.<T>empty();
- for (T each : this)
- {
- if (predicate.test(each))
- {
- mutableSet.add(each);
- }
- }
- return mutableSet;
+ return this.filter(predicate, mutableSet);
  }
 
  @Override
  default MutableSet<T> filterNot(Predicate<? super T> predicate)
  {
- var mutableSet = MutableSet.<T>empty();
- for (T each : this)
- {
- if (!predicate.test(each))
- {
- mutableSet.add(each);
- }
- }
- return mutableSet;
+ return this.filter(predicate.negate());
  }
 
  @Override
  default <V> MutableSet<V> map(Function<? super T, ? extends V> function)
  {
  var mutableSet = MutableSet.<V>empty();
- this.forEach(each -> mutableSet.add(function.apply(each)));
- return mutableSet;
+ return this.map(function, mutableSet);
  }
 
  @Override
  default <V> MutableSet<V> flatMap(Function<? super T, ? extends Iterable<V>> function)
  {
  var mutableSet = MutableSet.<V>empty();
- this.forEach(each -> mutableSet.addAllIterable(function.apply(each)));
- return mutableSet;
+ return this.flatMap(function, mutableSet);
  }
 
  default <K, V> MutableSetMultimap<K, T> groupBy(Function<? super T, ? extends K> function)

deck-of-cards-kata/src/main/java/bnymellon/codekatas/deckofcards/custom/collections/RichIterable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 The Bank of New York Mellon.
+ * Copyright 2023 The Bank of New York Mellon.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,19 +32,53 @@ public interface RichIterable<T> extends Iterable<T>
 
  boolean isEmpty();
 
+ default boolean notEmpty()
+ {
+ return !this.isEmpty();
+ }
+
  default Stream<T> stream()
  {
  throw new UnsupportedOperationException();
  }
 
  RichIterable<T> filter(Predicate<? super T> predicate);
 
+ default <R extends Collection<T>> R filter(Predicate<? super T> predicate, R target)
+ {
+ this.forEach(each ->
+ {
+ if (predicate.test(each))
+ {
+ target.add(each);
+ }
+ });
+ return target;
+ }
+
  RichIterable<T> filterNot(Predicate<? super T> predicate);
 
+ default <R extends Collection<T>> R filterNot(Predicate<? super T> predicate, R target)
+ {
+ return this.filter(predicate.negate(), target);
+ }
+
  <V> RichIterable<V> map(Function<? super T, ? extends V> function);
 
+ default <V, R extends Collection<V>> R map(Function<? super T, ? extends V> function, R target)
+ {
+ this.forEach(each -> target.add(function.apply(each)));
+ return target;
+ }
+
  <V> RichIterable<V> flatMap(Function<? super T, ? extends Iterable<V>> function);
 
+ default <V, R extends MutableCollection<V>> R flatMap(Function<? super T, ? extends Iterable<V>> function, R target)
+ {
+ this.forEach(each -> target.addAllIterable(function.apply(each)));
+ return target;
+ }
+
  default RichIterable<T> peek(Consumer<? super T> consumer)
  {
  this.forEach(consumer);
@@ -80,6 +114,11 @@ default boolean anyMatch(Predicate<? super T> predicate)
  return false;
  }
 
+ default <V> boolean containsBy(Function<? super T, ? extends V> function, V value)
+ {
+ return this.anyMatch(each -> value.equals(function.apply(each)));
+ }
+
  default boolean allMatch(Predicate<? super T> predicate)
  {
  for (T each : this)
@@ -147,10 +186,19 @@ default MutableSet<T> toSet()
  return this.toCollection(MutableSet::empty, Collection::add);
  }
 
+ default MutableBag<T> toBag()
+ {
+ return this.toCollection(MutableBag::empty, Collection::add);
+ }
+
  default <R extends Collection<T>> R toCollection(Supplier<R> supplier, BiConsumer<R, T> addMethod)
  {
  R collection = supplier.get();
  this.forEach(each -> addMethod.accept(collection, each));
  return collection;
  }
+
+ <K> Bag<K> countBy(Function<? super T, ? extends K> function);
+
+ <V> Bag<V> countByEach(Function<? super T, ? extends Iterable<V>> function);
 }

deck-of-cards-kata/src/test/java/bnymellon/codekatas/deckofcards/custom/collections/MutableListTest.java

@@ -22,6 +22,7 @@
 import java.util.Set;
 import java.util.stream.Collector;
 import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
@@ -412,4 +413,43 @@ public void addAllIterable()
  list2.addAllIterable(expected::iterator);
  Assertions.assertEquals(expected, list2);
  }
+
+ @Test
+ public void countByEach()
+ {
+ MutableList<MutableList<Integer>> list = MutableList.of(MutableList.of(1, 2), MutableList.of(1, 2, 3));
+ MutableBag<Integer> counts = list.countByEach(each -> each);
+ Assertions.assertEquals(2, counts.getOccurrences(1));
+ Assertions.assertEquals(2, counts.getOccurrences(2));
+ Assertions.assertEquals(1, counts.getOccurrences(3));
+ }
+
+ @Test
+ public void groupByEach()
+ {
+ MutableList<Integer> list = MutableList.of(1, 2, 3);
+ MutableListMultimap<Integer, Integer> multimap = list.groupByEach(each -> IntStream.range(0, each).boxed().toList());
+ Assertions.assertEquals(List.of(1, 2, 3), multimap.get(0));
+ Assertions.assertEquals(List.of(2, 3), multimap.get(1));
+ Assertions.assertEquals(List.of(3), multimap.get(2));
+ }
+
+ @Test
+ public void toBag()
+ {
+ MutableList<Integer> list = MutableList.of(1, 2, 2, 3, 3, 3);
+ MutableBag<Integer> bag = list.toBag();
+
+ Assertions.assertEquals(MutableBag.of(1, 2, 2, 3, 3, 3), bag);
+ }
+
+ @Test
+ public void containsBy()
+ {
+ MutableList<Integer> hasEvens = MutableList.of(1, 2, 3);
+ MutableList<Integer> onlyOdds = MutableList.of(1, 3);
+
+ Assertions.assertTrue(hasEvens.containsBy(each -> each % 2, 0));
+ Assertions.assertFalse(onlyOdds.containsBy(each -> each % 2, 0));
+ }
 }