1 files changed, 135 insertions, 0 deletions
diff --git a/base/src/main/java/bjc/utils/data/Pair.java b/base/src/main/java/bjc/utils/data/Pair.java
new file mode 100644
index 0000000..e6796ba
--- /dev/null
+++ b/base/src/main/java/bjc/utils/data/Pair.java
@@ -0,0 +1,135 @@
+package bjc.utils.data;
+
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+/**
+ * A pair of values, with nothing special about them.
+ *
+ * @author ben
+ *
+ * @param <LeftType>
+ *                The type of the left value
+ * @param <RightType>
+ *                The type of the right value
+ */
+public class Pair<LeftType, RightType> implements IPair<LeftType, RightType> {
+	// The left value
+	private LeftType leftValue;
+
+	// The right value
+	private RightType rightValue;
+
+	/**
+	 * Create a new pair with both sides set to null
+	 */
+	public Pair() {
+
+	}
+
+	/**
+	 * Create a new pair with both sides set to the specified values
+	 *
+	 * @param left
+	 *                The value of the left side
+	 * @param right
+	 *                The value of the right side
+	 */
+	public Pair(final LeftType left, final RightType right) {
+		leftValue = left;
+		rightValue = right;
+	}
+
+	@Override
+	public <BoundLeft, BoundRight> IPair<BoundLeft, BoundRight> bind(
+			final BiFunction<LeftType, RightType, IPair<BoundLeft, BoundRight>> binder) {
+		if (binder == null) throw new NullPointerException("Binder must not be null.");
+
+		return binder.apply(leftValue, rightValue);
+	}
+
+	@Override
+	public <BoundLeft> IPair<BoundLeft, RightType> bindLeft(
+			final Function<LeftType, IPair<BoundLeft, RightType>> leftBinder) {
+		if (leftBinder == null) throw new NullPointerException("Binder must not be null");
+
+		return leftBinder.apply(leftValue);
+	}
+
+	@Override
+	public <BoundRight> IPair<LeftType, BoundRight> bindRight(
+			final Function<RightType, IPair<LeftType, BoundRight>> rightBinder) {
+		if (rightBinder == null) throw new NullPointerException("Binder must not be null");
+
+		return rightBinder.apply(rightValue);
+	}
+
+	@Override
+	public <OtherLeft, OtherRight, CombinedLeft, CombinedRight> IPair<CombinedLeft, CombinedRight> combine(
+			final IPair<OtherLeft, OtherRight> otherPair,
+			final BiFunction<LeftType, OtherLeft, CombinedLeft> leftCombiner,
+			final BiFunction<RightType, OtherRight, CombinedRight> rightCombiner) {
+		return otherPair.bind((otherLeft, otherRight) -> {
+			final CombinedLeft left = leftCombiner.apply(leftValue, otherLeft);
+			final CombinedRight right = rightCombiner.apply(rightValue, otherRight);
+
+			return new Pair<>(left, right);
+		});
+	}
+
+	@Override
+	public <NewLeft> IPair<NewLeft, RightType> mapLeft(final Function<LeftType, NewLeft> mapper) {
+		if (mapper == null) throw new NullPointerException("Mapper must not be null");
+
+		return new Pair<>(mapper.apply(leftValue), rightValue);
+	}
+
+	@Override
+	public <NewRight> IPair<LeftType, NewRight> mapRight(final Function<RightType, NewRight> mapper) {
+		if (mapper == null) throw new NullPointerException("Mapper must not be null");
+
+		return new Pair<>(leftValue, mapper.apply(rightValue));
+	}
+
+	@Override
+	public <MergedType> MergedType merge(final BiFunction<LeftType, RightType, MergedType> merger) {
+		if (merger == null) throw new NullPointerException("Merger must not be null");
+
+		return merger.apply(leftValue, rightValue);
+	}
+
+	@Override
+	public String toString() {
+		return String.format("Pair [leftValue='%s', rightValue='%s']", leftValue, rightValue);
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+
+		result = prime * result + (leftValue == null ? 0 : leftValue.hashCode());
+		result = prime * result + (rightValue == null ? 0 : rightValue.hashCode());
+
+		return result;
+	}
+
+	@Override
+	public boolean equals(final Object obj) {
+		if (this == obj) return true;
+		if (obj == null) return false;
+		if (!(obj instanceof Pair<?, ?>)) return false;
+
+		final Pair<?, ?> other = (Pair<?, ?>) obj;
+
+		if (leftValue == null) {
+			if (other.leftValue != null) return false;
+		} else if (!leftValue.equals(other.leftValue)) return false;
+
+		if (rightValue == null) {
+			if (other.rightValue != null) return false;
+		} else if (!rightValue.equals(other.rightValue)) return false;
+
+		return true;
+	}
+}