1 files changed, 81 insertions, 0 deletions
diff --git a/src/main/java/bjc/data/internals/BoundListHolder.java b/src/main/java/bjc/data/internals/BoundListHolder.java
new file mode 100644
index 0000000..8f8cab4
--- /dev/null
+++ b/src/main/java/bjc/data/internals/BoundListHolder.java
@@ -0,0 +1,81 @@
+package bjc.data.internals;
+
+import java.util.function.Function;
+import java.util.function.UnaryOperator;
+
+import bjc.data.IHolder;
+import bjc.data.ListHolder;
+import bjc.funcdata.IList;
+
+/**
+ * Holds a list, converted into a holder.
+ *
+ * @author Ben Culkin
+ */
+@SuppressWarnings("javadoc")
+public class BoundListHolder<ContainedType> implements IHolder<ContainedType> {
+	/* The list of contained holders. */
+	private final IList<IHolder<ContainedType>> heldHolders;
+
+	/**
+	 * Create a new list of holders.
+	 *
+	 * @param toHold
+	 *        The list of holders to, well, hold.
+	 */
+	public BoundListHolder(final IList<IHolder<ContainedType>> toHold) {
+		heldHolders = toHold;
+	}
+
+	@Override
+	public <BoundType> IHolder<BoundType> bind(final Function<ContainedType, IHolder<BoundType>> binder) {
+		if(binder == null) throw new NullPointerException("Binder must not be null");
+
+		final IList<IHolder<BoundType>> boundHolders = heldHolders.map((containedHolder) -> {
+			return containedHolder.bind(binder);
+		});
+
+		return new BoundListHolder<>(boundHolders);
+	}
+
+	@Override
+	public <NewType> Function<ContainedType, IHolder<NewType>> lift(final Function<ContainedType, NewType> func) {
+		if(func == null) throw new NullPointerException("Function to lift must not be null");
+
+		return (val) -> {
+			return new ListHolder<>(func.apply(val));
+		};
+	}
+
+	@Override
+	public <MappedType> IHolder<MappedType> map(final Function<ContainedType, MappedType> mapper) {
+		if(mapper == null) throw new NullPointerException("Mapper must not be null");
+
+		final IList<IHolder<MappedType>> mappedHolders = heldHolders.map((containedHolder) -> {
+			return containedHolder.map(mapper);
+		});
+
+		return new BoundListHolder<>(mappedHolders);
+	}
+
+	@Override
+	public IHolder<ContainedType> transform(final UnaryOperator<ContainedType> transformer) {
+		if(transformer == null) throw new NullPointerException("Transformer must not be null");
+
+		heldHolders.forEach((containedHolder) -> {
+			containedHolder.transform(transformer);
+		});
+
+		return this;
+	}
+
+	@Override
+	public <UnwrappedType> UnwrappedType unwrap(final Function<ContainedType, UnwrappedType> unwrapper) {
+		if(unwrapper == null) throw new NullPointerException("Unwrapper must not be null");
+
+		/*
+		 * @NOTE Is there another way we could want to do this?
+		 */
+		return heldHolders.randItem().unwrap(unwrapper);
+	}
+}