1 files changed, 62 insertions, 0 deletions
diff --git a/base/src/main/java/bjc/utils/funcutils/GroupPartIteration.java b/base/src/main/java/bjc/utils/funcutils/GroupPartIteration.java
new file mode 100644
index 0000000..f3b2254
--- /dev/null
+++ b/base/src/main/java/bjc/utils/funcutils/GroupPartIteration.java
@@ -0,0 +1,62 @@
+package bjc.utils.funcutils;
+
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+import bjc.utils.funcdata.FunctionalList;
+import bjc.utils.funcdata.IList;
+
+/**
+ * Implements a single group partitioning pass on a list
+ *
+ * @author ben
+ *
+ * @param <E>
+ *                The type of element in the list being partitioned
+ */
+final class GroupPartIteration<E> implements Consumer<E> {
+	private final IList<IList<E>> returnedList;
+
+	public IList<E>		currentPartition;
+	private final IList<E>	rejectedItems;
+
+	private int		numberInCurrentPartition;
+	private final int	numberPerPartition;
+
+	private final Function<E, Integer> elementCounter;
+
+	public GroupPartIteration(final IList<IList<E>> returned, final IList<E> rejects, final int nPerPart,
+			final Function<E, Integer> eleCount) {
+		this.returnedList = returned;
+		this.rejectedItems = rejects;
+		this.numberPerPartition = nPerPart;
+		this.elementCounter = eleCount;
+
+		this.currentPartition = new FunctionalList<>();
+		this.numberInCurrentPartition = 0;
+	}
+
+	@Override
+	public void accept(final E value) {
+		final boolean shouldStartPartition = numberInCurrentPartition >= numberPerPartition;
+
+		if (shouldStartPartition) {
+			returnedList.add(currentPartition);
+
+			currentPartition = new FunctionalList<>();
+			numberInCurrentPartition = 0;
+		} else {
+			final int currentElementCount = elementCounter.apply(value);
+
+			final boolean shouldReject = numberInCurrentPartition
+					+ currentElementCount >= numberPerPartition;
+
+			if (shouldReject) {
+				rejectedItems.add(value);
+			} else {
+				currentPartition.add(value);
+				numberInCurrentPartition += currentElementCount;
+			}
+		}
+	}
+}