feat: gumtree simple is now the default matcher.

Author: jrfaller

core/src/main/java/com/github/gumtreediff/matchers/CompositeMatchers.java

@@ -21,6 +21,7 @@
 package com.github.gumtreediff.matchers;
 
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
@@ -39,7 +40,6 @@
 import com.github.gumtreediff.matchers.optimizations.LeafMoveMatcherThetaE;
 import com.github.gumtreediff.matchers.optimizations.UnmappedLeavesMatcherThetaC;
 import com.github.gumtreediff.tree.Tree;
-import com.google.common.collect.Sets;
 
 /**
  * A class defining the CompositeMatcher class, which is a pipeline of matchers.
@@ -73,28 +73,28 @@ public List<Matcher> matchers() {
 
         @Override
         public Set<ConfigurationOptions> getApplicableOptions() {
-            Set<ConfigurationOptions> allOptions = Sets.newHashSet();
+            Set<ConfigurationOptions> allOptions = new HashSet<>();
             for (Matcher matcher : matchers)
                 allOptions.addAll(matcher.getApplicableOptions());
 
             return allOptions;
         }
     }
 
-    @Register(id = "gumtree", priority = Registry.Priority.MAXIMUM)
-    public static class ClassicGumtree extends CompositeMatcher {
-        public ClassicGumtree() {
-            super(new GreedySubtreeMatcher(), new GreedyBottomUpMatcher());
-        }
-    }
-
     @Register(id = "gumtree-simple", priority = Registry.Priority.HIGH)
     public static class SimpleGumtree extends CompositeMatcher {
         public SimpleGumtree() {
             super(new GreedySubtreeMatcher(), new SimpleBottomUpMatcher());
         }
     }
 
+    @Register(id = "gumtree-classic", priority = Registry.Priority.HIGH)
+    public static class ClassicGumtree extends CompositeMatcher {
+        public ClassicGumtree() {
+            super(new GreedySubtreeMatcher(), new GreedyBottomUpMatcher());
+        }
+    }
+
     @Register(id = "gumtree-simple-stable", priority = Registry.Priority.HIGH)
     public static class SimpleGumtreeStable extends CompositeMatcher {
         public SimpleGumtreeStable() {