Factored interface out of GenHolder

1 files changed, 45 insertions, 0 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/data/IHolder.java b/BJC-Utils2/src/main/java/bjc/utils/data/IHolder.java
new file mode 100644
index 0000000..aa7d5bd
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/data/IHolder.java
@@ -0,0 +1,45 @@
+package bjc.utils.data;
+
+import java.util.function.Function;
+
+/**
+ * Generic interface for things that store a single value in a roughly
+ * monadic fashion
+ * 
+ * @author ben
+ *
+ * @param <T>
+ *            The type of data being stored
+ */
+public interface IHolder<T> {
+
+	/**
+	 * Return the result of applying the given transformation to the held
+	 * value Doesn't change the held value
+	 * 
+	 * @param f
+	 *            The transformation to apply
+	 * @return A holder with the transformed value
+	 */
+	<NewT> IHolder<NewT> map(Function<T, NewT> f);
+
+	/**
+	 * Apply the given transformation to the held value. Returns the holder
+	 * for allowing chaining of transforms
+	 * 
+	 * @param f
+	 *            The transform to apply to the value
+	 * @return The holder
+	 */
+	IHolder<T> transform(Function<T, T> f);
+
+	/**
+	 * Returns a raw mapped value, not contained in a GenHolder
+	 * 
+	 * @param f
+	 *            The function to use for mapping the value
+	 * @return The mapped value outside of a GenHolder
+	 */
+	<E> E unwrap(Function<T, E> f);
+
+}
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