From 8f32b5e359e6a875c1b3ec7d8b9a42e47c60a0ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juan=20Antonio=20Bre=C3=B1a=20Moral?=
 <bren@juanantonio.info>
Date: Wed, 29 May 2024 16:07:09 +0000
Subject: [PATCH] Adding initial examples for streams

---
 .../info/jab/fp/stream/StreamExamples.java    | 39 +++++++++++
 .../gatherers/_10_collector_as_gatherer.java  | 48 -------------
 .../info/jab/fp/stream/gatherers/_11_map.java | 24 -------
 .../fp/stream/gatherers/_12_windowFixed.java  | 42 -----------
 .../jab/fp/stream/gatherers/_13_fold.java     | 31 --------
 .../jab/fp/stream/gatherers/_14_reduce.java   | 36 ----------
 .../gatherers/_15_print_characteristics.java  | 39 -----------
 .../fp/stream/gatherers/_18_findIndex.java    | 27 -------
 .../stream/gatherers/_1_starting_thread.java  | 29 --------
 .../gatherers/_20_gatherer_windowBy.java      | 54 --------------
 .../gatherers/_21_windowByWithCollector.java  | 70 -------------------
 .../fp/stream/gatherers/_2_take_while.java    | 27 -------
 .../jab/fp/stream/gatherers/_3_limit.java     | 34 ---------
 .../jab/fp/stream/gatherers/_4_groupBy2.java  | 45 ------------
 .../gatherers/_5_groupBy2_sequential.java     | 44 ------------
 .../fp/stream/gatherers/_6_filter_greedy.java | 27 -------
 .../_7_groupBy2_sequential_greedy.java        | 45 ------------
 17 files changed, 39 insertions(+), 622 deletions(-)
 create mode 100644 training/src/main/java/info/jab/fp/stream/StreamExamples.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_10_collector_as_gatherer.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_11_map.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_12_windowFixed.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_13_fold.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_14_reduce.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_15_print_characteristics.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_18_findIndex.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_1_starting_thread.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_20_gatherer_windowBy.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_21_windowByWithCollector.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_2_take_while.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_3_limit.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_4_groupBy2.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_5_groupBy2_sequential.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_6_filter_greedy.java
 delete mode 100644 training/src/main/java/info/jab/fp/stream/gatherers/_7_groupBy2_sequential_greedy.java

diff --git a/training/src/main/java/info/jab/fp/stream/StreamExamples.java b/training/src/main/java/info/jab/fp/stream/StreamExamples.java
new file mode 100644
index 0000000..f577187
--- /dev/null
+++ b/training/src/main/java/info/jab/fp/stream/StreamExamples.java
@@ -0,0 +1,39 @@
+package info.jab.fp.stream;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Gatherers;
+
+public class StreamExamples {
+    
+    public void example1() {
+          var text = """
+                item1
+                item2
+                --
+                item11
+                item12
+                """;
+
+        var result = text.lines()
+        .gather(Gatherers.windowFixed(2))
+        .toList();
+    }
+
+    public void example2() {
+        var text = """
+            item1
+            item2
+            --
+            item11
+            item12
+            """;
+      
+        var result = text.lines()
+            .gather(Gatherers.fold(() -> 0, (value, s) -> value + 1))
+            .findFirst().orElseThrow();
+      
+        System.out.println(result);
+    }
+
+}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_10_collector_as_gatherer.java b/training/src/main/java/info/jab/fp/stream/gatherers/_10_collector_as_gatherer.java
deleted file mode 100644
index 0dace92..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_10_collector_as_gatherer.java
+++ /dev/null
@@ -1,48 +0,0 @@
-import java.util.List;
-import java.util.stream.Collector;
-import java.util.stream.Collectors;
-import java.util.stream.Gatherer;
-import java.util.stream.Gatherers;
-
-<E, A, T> Gatherer<E, A, T> asGatherer(Collector<? super E, A, ? extends T> collector) {
-  var supplier = collector.supplier();
-  var accumulator = collector.accumulator();
-  var combiner = collector.combiner();
-  var finisher = collector.finisher();
-  return Gatherer.of(supplier,
-      Gatherer.Integrator.ofGreedy((state, element, _) -> {
-        accumulator.accept(state, element);
-        return true;
-      }),
-      combiner,
-      (state, downstream) -> downstream.push(finisher.apply(state)));
-}
-
-<E, A, T> Collector<E, A, T> asCollector(Gatherer<? super E, A, T> gatherer) {
-  var initializer = gatherer.initializer();
-  var integrator = gatherer.integrator();
-  var combiner = gatherer.combiner();
-  var finisher = gatherer.finisher();
-  return Collector.of(
-    initializer,
-    (state, element) -> integrator.integrate(state, element, __ -> { throw new IllegalStateException(); }),
-    combiner,
-     state -> {
-      var box = new Object() { T result; };
-      finisher.accept(state, value -> { box.result = value; return true; });
-      return box.result;
-    });
-}
-
-void main() {
-  var list = List.of(1, 2, 3, 4, 5);
-
-  var result = list.stream()
-      .gather(asGatherer(Collectors.toList()))
-      .findFirst().orElseThrow();
-  System.out.println(result);
-
-  var result2 = list.stream()
-      .collect(asCollector(Gatherers.fold(() -> 0, Integer::sum)));
-  System.out.println(result2);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_11_map.java b/training/src/main/java/info/jab/fp/stream/gatherers/_11_map.java
deleted file mode 100644
index fee1bab..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_11_map.java
+++ /dev/null
@@ -1,24 +0,0 @@
-import java.util.stream.Gatherer;
-
-Gatherer<String, ?, Integer> map() {
-  return Gatherer.of(Gatherer.Integrator.ofGreedy((_, element, downstream) -> {
-    return downstream.push(element.length());
-  }));
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.map(String::length)
-      .gather(map())
-      .toList();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_12_windowFixed.java b/training/src/main/java/info/jab/fp/stream/gatherers/_12_windowFixed.java
deleted file mode 100644
index 328a9ec..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_12_windowFixed.java
+++ /dev/null
@@ -1,42 +0,0 @@
-import java.util.ArrayList;
-import java.util.List;
-import java.util.stream.Gatherer;
-
-Gatherer<String, ?, List<String>> windowFixed() {
-  return Gatherer.ofSequential(
-      () -> new Object() { List<String> list = new ArrayList<>(); },
-      Gatherer.Integrator.ofGreedy((state, element, downstream) -> {
-        if (state.list.size() == 2) {
-          if (!downstream.push(state.list)) {
-            return false;
-          }
-          state.list = new ArrayList<>();
-        }
-        state.list.add(element);
-        return true;
-      }),
-      (state, downstream) -> {
-        if (!state.list.isEmpty()) {
-          downstream.push(state.list);
-        }
-        state.list = null;  // maybe ?
-      }
-  );
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.gather(Gatherers.windowFixed(2))
-      .gather(windowFixed())
-      .toList();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_13_fold.java b/training/src/main/java/info/jab/fp/stream/gatherers/_13_fold.java
deleted file mode 100644
index c7e08bd..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_13_fold.java
+++ /dev/null
@@ -1,31 +0,0 @@
-import java.util.stream.Gatherer;
-
-Gatherer<String, ?, Integer> fold() {
-  return Gatherer.ofSequential(
-      () -> new Object() { int counter; },
-      Gatherer.Integrator.ofGreedy((state, _, _) -> {
-        state.counter++;
-        return true;
-      }),
-      (state, downstream) -> {
-        downstream.push(state.counter);
-      }
-  );
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.gather(Gatherers.fold(() -> 0, (value, s) -> value + 1))
-      .gather(fold())
-      .findFirst().orElseThrow();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_14_reduce.java b/training/src/main/java/info/jab/fp/stream/gatherers/_14_reduce.java
deleted file mode 100644
index b36a705..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_14_reduce.java
+++ /dev/null
@@ -1,36 +0,0 @@
-import java.util.stream.Gatherer;
-
-Gatherer<String, ?, Integer> reduce() {
-  class Counter {
-    int counter;
-    Counter(int counter) {
-      this.counter = counter;
-    }
-  }
-  return Gatherer.of(
-      () -> new Counter(0),
-      Gatherer.Integrator.ofGreedy((state, _, _) -> {
-        state.counter++;
-        return true;
-      }),
-      (s1, s2) -> new Counter(s1.counter + s2.counter),
-      (state, downstream) -> downstream.push(state.counter)
-  );
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      .parallel()
-      .gather(reduce())
-      .findFirst().orElseThrow();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_15_print_characteristics.java b/training/src/main/java/info/jab/fp/stream/gatherers/_15_print_characteristics.java
deleted file mode 100644
index cea0793..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_15_print_characteristics.java
+++ /dev/null
@@ -1,39 +0,0 @@
-import java.util.EnumSet;
-import java.util.List;
-import java.util.Set;
-import java.util.function.Consumer;
-import java.util.stream.Collectors;
-import java.util.stream.Gatherer;
-import java.util.stream.Gatherers;
-import java.util.stream.Stream;
-
-import static java.util.stream.Collectors.joining;
-
-enum Characteristic {
-  SEQUENTIAL, STATELESS, GREEDY
-}
-
-Set<Characteristic> characteristics(Gatherer<?,?, ?> gatherer) {
-  return Stream.of(gatherer)
-      .<Characteristic>mapMulti((g, consumer) -> {
-        if (g.combiner() == Gatherer.defaultCombiner()) {
-          consumer.accept(Characteristic.SEQUENTIAL);
-        }
-        if (g.initializer() == Gatherer.defaultInitializer()) {
-          consumer.accept(Characteristic.STATELESS);
-        }
-        if (g.integrator() instanceof Gatherer.Integrator.Greedy<?,?,?>) {
-          consumer.accept(Characteristic.GREEDY);
-        }
-      })
-      .collect(Collectors.toCollection(() -> EnumSet.noneOf(Characteristic.class)));
-}
-
-void main() {
-  // Gatherers
-  System.out.println("fold: " + characteristics(Gatherers.fold(() -> null, (_, _) -> null)));
-  System.out.println("scan: " + characteristics(Gatherers.scan(() -> null, (_, _) -> null)));
-  System.out.println("mapConcurrent: " + characteristics(Gatherers.mapConcurrent(10, _ -> null)));
-  System.out.println("windowFixed: " + characteristics(Gatherers.windowFixed(2)));
-  System.out.println("windowSliding: " + characteristics(Gatherers.windowSliding(2)));
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_18_findIndex.java b/training/src/main/java/info/jab/fp/stream/gatherers/_18_findIndex.java
deleted file mode 100644
index cf31ed9..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_18_findIndex.java
+++ /dev/null
@@ -1,27 +0,0 @@
-import java.lang.foreign.Arena;
-import java.util.Objects;
-import java.util.function.Predicate;
-import java.util.stream.Gatherer;
-
-import static java.util.stream.Gatherer.Integrator.ofGreedy;
-
-<T> Gatherer<T, ?, Integer> findIndex(Predicate<? super T> predicate) {
-  Objects.requireNonNull(predicate);
-  return Gatherer.ofSequential(
-      () -> new Object() { int index; },
-      ofGreedy((state, element, downstream) -> {
-        var index = state.index++;
-        if (predicate.test(element)) {
-          return downstream.push(index);
-        }
-        return true;
-      }));
-}
-
-void main() {
-  var list = java.util.List.of("foo", "bar", "baz");
-  var findIndex = list.stream().gather(findIndex(s -> s.contains("o"))).findFirst().orElse(-1);
-  System.out.println(findIndex);
-  var findLastIndex = list.reversed().stream().gather(findIndex(s -> s.contains("o"))).findFirst().orElse(-1);
-  System.out.println(findLastIndex);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_1_starting_thread.java b/training/src/main/java/info/jab/fp/stream/gatherers/_1_starting_thread.java
deleted file mode 100644
index e35bfcd..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_1_starting_thread.java
+++ /dev/null
@@ -1,29 +0,0 @@
-import java.util.stream.Gatherer;
-
-Gatherer<String, ?, String> filter() {
-  return Gatherer.of((_, element, downstream) -> {
-    if (element.endsWith("1")) {
-      return downstream.push(element);
-    }
-    return true;
-  });
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.filter(s -> s.endsWith("1"))
-      .gather(filter())
-      .toList();
-
-  System.out.println(result);
-}
-
-
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_20_gatherer_windowBy.java b/training/src/main/java/info/jab/fp/stream/gatherers/_20_gatherer_windowBy.java
deleted file mode 100644
index fd822da..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_20_gatherer_windowBy.java
+++ /dev/null
@@ -1,54 +0,0 @@
-import java.util.ArrayList;
-import java.util.List;
-import java.util.function.BiFunction;
-import java.util.function.Predicate;
-import java.util.stream.Gatherer;
-
-record Section(String name, List<String> items) {}
-
-Gatherer<String, ?, Section> windowBy(Predicate<? super String> predicate,
-                                      BiFunction<? super String, ? super List<String>, ? extends Section> mapper) {
-  class State {
-    List<String> container;
-    String name;
-  }
-  return Gatherer.ofSequential(
-      State::new,
-      Gatherer.Integrator.ofGreedy((state, element, downstream) -> {
-        if (predicate.test(element)) {
-          if (state.container != null) {
-            if (!downstream.push(mapper.apply(state.name, state.container))) {
-              return false;
-            }
-          }
-          state.container = new ArrayList<>();
-          state.name = element;
-          return true;
-        }
-        if (state.container == null) {
-          throw new IllegalStateException();
-        }
-        state.container.add(element);
-        return true;
-      }),
-      (state, downstream) -> {
-        if (state.container != null) {
-          downstream.push(mapper.apply(state.name, state.container));
-        }
-      });
-}
-
-void main() {
-  var text = """
-      header
-      item1
-      item2
-      header2
-      item3
-      """;
-
-  var sections = text.lines()
-      .gather(windowBy(s -> s.startsWith("header"), Section::new))
-      .toList();
-  System.out.println(sections);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_21_windowByWithCollector.java b/training/src/main/java/info/jab/fp/stream/gatherers/_21_windowByWithCollector.java
deleted file mode 100644
index f411a46..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_21_windowByWithCollector.java
+++ /dev/null
@@ -1,70 +0,0 @@
-import java.util.List;
-import java.util.Objects;
-import java.util.function.BiFunction;
-import java.util.function.Predicate;
-import java.util.stream.Collector;
-import java.util.stream.Collectors;
-import java.util.stream.Gatherer;
-
-record Section(String name, List<String> items) {}
-
-<T, R, R2> Gatherer<T, ?, R2> windowBy(Predicate<? super T> predicate,
-                                       Collector<? super T, ?, ? extends R> collector,
-                                       BiFunction<? super T, ? super R, ? extends R2> mapper) {
-  return _windowBy(predicate, collector, mapper);
-}
-
-<T, A, R, R2> Gatherer<T, ?, R2> _windowBy(Predicate<? super T> predicate,
-                                           Collector<? super T, A, ? extends R> collector,
-                                           BiFunction<? super T, ? super R, ? extends R2> mapper) {
-  Objects.requireNonNull(predicate);
-  Objects.requireNonNull(collector);
-  Objects.requireNonNull(mapper);
-  var supplier = collector.supplier();
-  var accumulator = collector.accumulator();
-  var finisher = collector.finisher();
-  class State {
-    A container;
-    T element;
-  }
-  return Gatherer.ofSequential(
-      State::new,
-      Gatherer.Integrator.ofGreedy((state, element, downstream) -> {
-        if (predicate.test(element)) {
-          if (state.container != null) {
-            if (!downstream.push(mapper.apply(state.element, finisher.apply(state.container)))) {
-              return false;
-            }
-          }
-          state.container = supplier.get();
-          state.element = element;
-          return true;
-        }
-        if (state.container == null) {
-          throw new IllegalStateException("");
-        }
-        accumulator.accept(state.container, element);
-        return true;
-      }),
-      (state, downstream) -> {
-        if (state.container != null) {
-          downstream.push(mapper.apply(state.element, finisher.apply(state.container)));
-        }
-      }
-  );
-}
-
-void main() {
-  var text = """
-      header
-      item1
-      item2
-      header2
-      item3
-      """;
-
-  var sections = text.lines()
-      .gather(windowBy(s -> s.startsWith("header"), Collectors.toList(), Section::new))
-      .toList();
-  System.out.println(sections);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_2_take_while.java b/training/src/main/java/info/jab/fp/stream/gatherers/_2_take_while.java
deleted file mode 100644
index 1ffe110..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_2_take_while.java
+++ /dev/null
@@ -1,27 +0,0 @@
-import java.util.stream.Gatherer;
-
-Gatherer<String, ?, String> takeWhile() {
-  return Gatherer.of((_, element, downstream) -> {
-    if (element.startsWith("item")) {
-      return downstream.push(element);
-    }
-    return false;
-  });
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.takeWhile(s -> s.startsWith("item"))
-      .gather(takeWhile())
-      .toList();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_3_limit.java b/training/src/main/java/info/jab/fp/stream/gatherers/_3_limit.java
deleted file mode 100644
index bddfe2b..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_3_limit.java
+++ /dev/null
@@ -1,34 +0,0 @@
-import java.util.stream.Gatherer;
-
-Gatherer<String, ?, String> limit() {
-  class Counter {
-    int counter;
-    Counter(int counter) { this.counter = counter; }
-  }
-  return Gatherer.ofSequential(
-      () -> new Counter(0),
-      (counter, element, downstream) -> {
-        if (counter.counter++ == 3) {
-          return false;
-        }
-        return downstream.push(element);
-      }
-  );
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.limit(3)
-      .gather(limit())
-      .toList();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_4_groupBy2.java b/training/src/main/java/info/jab/fp/stream/gatherers/_4_groupBy2.java
deleted file mode 100644
index aa71f07..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_4_groupBy2.java
+++ /dev/null
@@ -1,45 +0,0 @@
-import java.util.ArrayList;
-import java.util.List;
-import java.util.stream.Gatherer;
-import java.util.stream.Gatherers;
-
-Gatherer<String, ?, List<String>> groupBy2() {
-  class State {
-    ArrayList<String> list = new ArrayList<>();
-  }
-  return Gatherer.of(
-      State::new,
-      (state, element, downstream) -> {
-        var list = state.list;
-        list.add(element);
-        if (state.list.size() == 2) {
-          state.list = new ArrayList<>();
-          return downstream.push(list);
-        }
-        return true;
-      },
-      (_, _) -> { throw new UnsupportedOperationException(); },   // oops !
-      (state, downstream) -> {
-        if (!state.list.isEmpty()) {
-          downstream.push(state.list);
-        }
-      }
-  );
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.gather(Gatherers.windowFixed(2)
-      .gather(groupBy2())
-      .toList();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_5_groupBy2_sequential.java b/training/src/main/java/info/jab/fp/stream/gatherers/_5_groupBy2_sequential.java
deleted file mode 100644
index be9c443..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_5_groupBy2_sequential.java
+++ /dev/null
@@ -1,44 +0,0 @@
-import java.util.ArrayList;
-import java.util.List;
-import java.util.stream.Gatherer;
-import java.util.stream.Gatherers;
-
-Gatherer<String, ?, List<String>> groupBy2() {
-  class State {
-    ArrayList<String> list = new ArrayList<>();
-  }
-  return Gatherer.ofSequential(   // inherently sequential
-      State::new,
-      (state, element, downstream) -> {
-        var list = state.list;
-        list.add(element);
-        if (state.list.size() == 2) {
-          state.list = new ArrayList<>();
-          return downstream.push(list);
-        }
-        return true;
-      },
-      (state, downstream) -> {
-        if (!state.list.isEmpty()) {
-          downstream.push(state.list);
-        }
-      }
-  );
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.gather(Gatherers.windowFixed(2)
-      .gather(groupBy2())
-      .toList();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_6_filter_greedy.java b/training/src/main/java/info/jab/fp/stream/gatherers/_6_filter_greedy.java
deleted file mode 100644
index 59c0c35..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_6_filter_greedy.java
+++ /dev/null
@@ -1,27 +0,0 @@
-import java.util.stream.Gatherer;
-
-Gatherer<String, ?, String> filter() {
-  return Gatherer.of(Gatherer.Integrator.ofGreedy((_, element, downstream) -> {  // ofGreedy: optimization
-    if (element.endsWith("1")) {
-      return downstream.push(element);
-    }
-    return true;
-  }));
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.filter(s -> s.endsWith("1"))
-      .gather(filter())
-      .toList();
-
-  System.out.println(result);
-}
diff --git a/training/src/main/java/info/jab/fp/stream/gatherers/_7_groupBy2_sequential_greedy.java b/training/src/main/java/info/jab/fp/stream/gatherers/_7_groupBy2_sequential_greedy.java
deleted file mode 100644
index 6f26552..0000000
--- a/training/src/main/java/info/jab/fp/stream/gatherers/_7_groupBy2_sequential_greedy.java
+++ /dev/null
@@ -1,45 +0,0 @@
-import java.util.ArrayList;
-import java.util.List;
-import java.util.stream.Gatherer;
-import java.util.stream.Gatherer.Integrator;
-import java.util.stream.Gatherers;
-
-Gatherer<String, ?, List<String>> groupBy2() {
-  class State {
-    ArrayList<String> list = new ArrayList<>();
-  }
-  return Gatherer.ofSequential(   // inherently sequential
-      State::new,
-      Integrator.ofGreedy((state, element, downstream) -> {
-        var list = state.list;
-        list.add(element);
-        if (state.list.size() == 2) {
-          state.list = new ArrayList<>();
-          return downstream.push(list);
-        }
-        return true;
-      }),
-      (state, downstream) -> {
-        if (!state.list.isEmpty()) {
-          downstream.push(state.list);
-        }
-      }
-  );
-}
-
-void main() {
-  var text = """
-      item1
-      item2
-      --
-      item11
-      item12
-      """;
-
-  var result = text.lines()
-      //.gather(Gatherers.windowFixed(2)
-      .gather(groupBy2())
-      .toList();
-
-  System.out.println(result);
-}