Rename package root

The package root is now bjc, not io.github.bculkin2442.

1 files changed, 60 insertions, 0 deletions

diff --git a/src/main/java/bjc/data/GeneratingIterator.java b/src/main/java/bjc/data/GeneratingIterator.java
new file mode 100644
index 0000000..9adda6f
--- /dev/null
+++ b/src/main/java/bjc/data/GeneratingIterator.java
@@ -0,0 +1,60 @@
+package bjc.data;
+
+import java.util.Iterator;
+import java.util.function.Predicate;
+import java.util.function.UnaryOperator;
+
+/**
+ * An iterator that generates a series of elements from a single element.
+ * 
+ * @author bjculkin
+ *
+ * @param <E>
+ *        The type of element generated.
+ */
+public class GeneratingIterator<E> implements Iterator<E> {
+	/* Our current state. */
+	private E state;
+	/* The function to use to transition states. */
+	private UnaryOperator<E> transtion;
+	/* The predicate to indicate where to stop. */
+	private Predicate<E> stpper;
+
+	/**
+	 * Create a new generative iterator.
+	 * 
+	 * @param initial
+	 *        The initial state of the generator.
+	 * 
+	 * @param transition
+	 *        The function to apply to the state.
+	 * 
+	 * @param stopper
+	 *        The predicate applied to the current state to determine when
+	 *        to stop.
+	 */
+	public GeneratingIterator(E initial, UnaryOperator<E> transition, Predicate<E> stopper) {
+		state = initial;
+		transtion = transition;
+		stpper = stopper;
+	}
+
+	@Override
+	public boolean hasNext() {
+		return stpper.test(state);
+	}
+
+	/*
+	 * @NOTE
+	 *
+	 * As this currently is, it only works correctly assuming that next() is
+	 * only called when hasNext() is true. Should we safeguard against
+	 * people who are not doing the right thing?
+	 */
+	@Override
+	public E next() {
+		state = transtion.apply(state);
+
+		return state;
+	}
+}