1 files changed, 104 insertions, 0 deletions
diff --git a/BJC-Utils2/src/main/java/bjc/utils/data/BoundLazyPair.java b/BJC-Utils2/src/main/java/bjc/utils/data/BoundLazyPair.java
new file mode 100644
index 0000000..41ab99b
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/data/BoundLazyPair.java
@@ -0,0 +1,104 @@
+package bjc.utils.data;
+
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+class BoundLazyPair<OldLeft, OldRight, NewLeft, NewRight>
+		implements IPair<NewLeft, NewRight> {
+	private Supplier<OldLeft>										leftSupplier;
+	private Supplier<OldRight>										rightSupplier;
+
+	private BiFunction<OldLeft, OldRight, IPair<NewLeft, NewRight>>	binder;
+
+	private IPair<NewLeft, NewRight>								boundPair;
+
+	private boolean													pairBound;
+
+	public BoundLazyPair(Supplier<OldLeft> leftSupp,
+			Supplier<OldRight> rightSupp,
+			BiFunction<OldLeft, OldRight, IPair<NewLeft, NewRight>> bindr) {
+		leftSupplier = leftSupp;
+		rightSupplier = rightSupp;
+		binder = bindr;
+	}
+
+	@Override
+	public <BoundLeft> IPair<BoundLeft, NewRight> bindLeft(
+			Function<NewLeft, IPair<BoundLeft, NewRight>> leftBinder) {
+		Supplier<NewLeft> leftSupp = () -> {
+			IPair<NewLeft, NewRight> newPair = boundPair;
+
+			if (!pairBound) {
+				newPair = binder.apply(leftSupplier.get(),
+						rightSupplier.get());
+			}
+
+			return newPair.getLeft();
+		};
+
+		return new HalfBoundLazyPair<>(leftSupp, leftBinder);
+	}
+
+	@Override
+	public <BoundRight> IPair<NewLeft, BoundRight> bindRight(
+			Function<NewRight, IPair<NewLeft, BoundRight>> rightBinder) {
+		Supplier<NewRight> rightSupp = () -> {
+			IPair<NewLeft, NewRight> newPair = boundPair;
+
+			if (!pairBound) {
+				newPair = binder.apply(leftSupplier.get(),
+						rightSupplier.get());
+			}
+
+			return newPair.getRight();
+		};
+
+		return new HalfBoundLazyPair<>(rightSupp, rightBinder);
+	}
+
+	@Override
+	public <BoundLeft, BoundRight> IPair<BoundLeft, BoundRight> bind(
+			BiFunction<NewLeft, NewRight, IPair<BoundLeft, BoundRight>> bindr) {
+		IHolder<IPair<NewLeft, NewRight>> newPair = new Identity<>(
+				boundPair);
+		IHolder<Boolean> newPairMade = new Identity<>(pairBound);
+
+		Supplier<NewLeft> leftSupp = () -> {
+			if (!newPairMade.getValue()) {
+				newPair.replace(binder.apply(leftSupplier.get(),
+						rightSupplier.get()));
+
+				newPairMade.replace(false);
+			}
+
+			return newPair.unwrap((pair) -> pair.getLeft());
+		};
+
+		Supplier<NewRight> rightSupp = () -> {
+			if (!newPairMade.getValue()) {
+				newPair.replace(binder.apply(leftSupplier.get(),
+						rightSupplier.get()));
+
+				newPairMade.replace(false);
+			}
+
+			return newPair.unwrap((pair) -> pair.getRight());
+		};
+
+		return new BoundLazyPair<>(leftSupp, rightSupp, bindr);
+	}
+
+	@Override
+	public <MergedType> MergedType merge(
+			BiFunction<NewLeft, NewRight, MergedType> merger) {
+		if (!pairBound) {
+			boundPair = binder.apply(leftSupplier.get(),
+					rightSupplier.get());
+
+			pairBound = true;
+		}
+
+		return boundPair.merge(merger);
+	}
+}
+\ No newline at end of file