1 files changed, 89 insertions, 0 deletions
diff --git a/src/main/java/bjc/optics/AdapterX.java b/src/main/java/bjc/optics/AdapterX.java
new file mode 100644
index 0000000..f037508
--- /dev/null
+++ b/src/main/java/bjc/optics/AdapterX.java
@@ -0,0 +1,89 @@
+/* 
+ * esodata - data structures of varying utility
+ * 
+ * Copyright 2022, Ben Culkin
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *   
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package bjc.optics;
+
+import java.util.function.Function;
+
+/**
+ * An adapter that maps between two sets of types
+ * 
+ * @author bjcul
+ *
+ * @param <F1> The type of the first source
+ * @param <F2> The type of the second source
+ * @param <T1> The type of the first destination
+ * @param <T2> The type of the second destination
+ */
+public interface AdapterX<F1, F2, T1, T2> extends Optic<F1, F2, T1, T2> {
+
+	/**
+	 * Create a source from a destination
+	 * 
+	 * @param source The destination to use
+	 * 
+	 * @return A source corresponding to the destination
+	 */
+	F1 from(T1 source);
+
+	/**
+	 * Create a destination from a source
+	 * 
+	 * @param source The source to use
+	 * 
+	 * @return A destination corresponding to the source
+	 */
+	T2 to(F2 source);
+
+	/**
+	 * Create an adapter from its component parts
+	 * 
+	 * @param <F1> The type of the first source
+	 * @param <F2> The type of the second source
+	 * @param <T1> The type of the first destination
+	 * @param <T2> The type of the second destination
+	 * 
+	 * @param f    The 'from' function
+	 * @param g    The 'to' function
+	 * 
+	 * @return The adapter constructed from the given parts.
+	 */
+	public static <F1, F2, T1, T2> AdapterX<F1, F2, T1, T2> of(Function<T1, F1> f, Function<F2, T2> g) {
+		return new FunctionalAdapterX<>(f, g);
+	}
+}
+
+final class FunctionalAdapterX<W1, W2, P1, P2> implements AdapterX<W1, W2, P1, P2> {
+	private final Function<P1, W1> f;
+	private final Function<W2, P2> g;
+
+	public FunctionalAdapterX(Function<P1, W1> f, Function<W2, P2> g) {
+		this.f = f;
+		this.g = g;
+	}
+
+	@Override
+	public W1 from(P1 source) {
+		return f.apply(source);
+	}
+
+	@Override
+	public P2 to(W2 source) {
+		return g.apply(source);
+	}
+}