From 0511c58b13b0604baefefc3333997ddae946100c Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sun, 24 Sep 2017 00:12:25 -0700
Subject: [PATCH] Remove the Pattern's dependency on java.util.function

---
 .../org/nwapw/abacus/lexing/pattern/Pattern.java |  7 +++----
 .../abacus/lexing/pattern/Transformation.java    | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 4 deletions(-)
 create mode 100644 core/src/main/java/org/nwapw/abacus/lexing/pattern/Transformation.java

diff --git a/core/src/main/java/org/nwapw/abacus/lexing/pattern/Pattern.java b/core/src/main/java/org/nwapw/abacus/lexing/pattern/Pattern.java
index b578d01..2090203 100644
--- a/core/src/main/java/org/nwapw/abacus/lexing/pattern/Pattern.java
+++ b/core/src/main/java/org/nwapw/abacus/lexing/pattern/Pattern.java
@@ -6,7 +6,6 @@ import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Stack;
-import java.util.function.Function;
 
 /**
  * A pattern that can be compiled from a string and used in lexing.
@@ -36,8 +35,8 @@ public class Pattern<T> {
      * A map of regex operator to functions that modify a PatternChain
      * with the appropriate operation.
      */
-    private Map<Character, Function<PatternChain<T>, PatternChain<T>>> operations =
-            new HashMap<Character, Function<PatternChain<T>, PatternChain<T>>>() {{
+    private Map<Character, Transformation<T>> operations =
+            new HashMap<Character, Transformation<T>>() {{
                 put('+', Pattern.this::transformPlus);
                 put('*', Pattern.this::transformStar);
                 put('?', Pattern.this::transformQuestion);
@@ -207,7 +206,7 @@ public class Pattern<T> {
             if (operations.containsKey(currentChar)) {
                 if (currentChain == null) return null;
 
-                currentChain = operations.get(currentChar).apply(currentChain);
+                currentChain = operations.get(currentChar).transform(currentChain);
                 fullChain.append(currentChain);
                 currentChain = null;
                 index++;
diff --git a/core/src/main/java/org/nwapw/abacus/lexing/pattern/Transformation.java b/core/src/main/java/org/nwapw/abacus/lexing/pattern/Transformation.java
new file mode 100644
index 0000000..5bab0e8
--- /dev/null
+++ b/core/src/main/java/org/nwapw/abacus/lexing/pattern/Transformation.java
@@ -0,0 +1,16 @@
+package org.nwapw.abacus.lexing.pattern;
+
+/**
+ * An interface that transforms a pattern chain into a different pattern chain.
+ * @param <T> the type used to identify the nodes in the pattern chain.
+ */
+public interface Transformation<T> {
+
+    /**
+     * Performs the actual transformation.
+     * @param from the original chain.
+     * @return the resulting chain.
+     */
+    PatternChain<T> transform(PatternChain<T> from);
+
+}