relax type-constraint on LearnerConstructor

It seems that Java cannot easily convert method references to the interface which sometimes requires boilerplate code.
Since the type is constrained by the call-site (e.g. learners) anyway, just drop it.

Author: mtf90

algorithms/active/procedural/src/test/java/de/learnlib/algorithm/procedural/sba/OptimizationsTest.java

@@ -17,8 +17,6 @@
 
 import java.util.Arrays;
 
-import de.learnlib.algorithm.LearnerConstructor;
-import de.learnlib.algorithm.procedural.SymbolWrapper;
 import de.learnlib.algorithm.procedural.adapter.dfa.TTTAdapterDFA;
 import de.learnlib.algorithm.procedural.sba.manager.OptimizingATManager;
 import de.learnlib.oracle.equivalence.EQOracleChain;
@@ -55,9 +53,7 @@ public void testOptimizations() {
         final SimulatorEQOracle<Character> eqo2 = new SimulatorEQOracle<>(sba);
         final EQOracleChain<SBA<?, Character>, Character, Boolean> eqo = new EQOracleChain<>(Arrays.asList(eqo1, eqo2));
 
-        final LearnerConstructor<TTTAdapterDFA<SymbolWrapper<Character>>, SymbolWrapper<Character>, Boolean> cons =
-                TTTAdapterDFA::new;
-        final SBALearner<Character, ?> learner = new SBALearner<>(alphabet, mqo, cons);
+        final SBALearner<Character, ?> learner = new SBALearner<>(alphabet, mqo, TTTAdapterDFA::new);
 
         final Experiment<SBA<?, Character>> experiment = new Experiment<>(learner, eqo, alphabet);
 

algorithms/active/procedural/src/test/java/de/learnlib/algorithm/procedural/spmm/OptimizationsTest.java

@@ -17,8 +17,6 @@
 
 import java.util.Arrays;
 
-import de.learnlib.algorithm.LearnerConstructor;
-import de.learnlib.algorithm.procedural.SymbolWrapper;
 import de.learnlib.algorithm.procedural.adapter.mealy.TTTAdapterMealy;
 import de.learnlib.algorithm.procedural.spmm.manager.OptimizingATManager;
 import de.learnlib.oracle.equivalence.EQOracleChain;
@@ -56,10 +54,8 @@ public void testOptimizations() {
         final EQOracleChain<SPMM<?, Character, ?, Character>, Character, Word<Character>> eqo =
                 new EQOracleChain<>(Arrays.asList(eqo1, eqo2));
 
-        final LearnerConstructor<TTTAdapterMealy<SymbolWrapper<Character>, Character>, SymbolWrapper<Character>, Word<Character>>
-                cons = TTTAdapterMealy::new;
-        final SPMMLearner<Character, Character, TTTAdapterMealy<SymbolWrapper<Character>, Character>> learner =
-                new SPMMLearner<>(alphabet, spmm.getErrorOutput(), mqo, cons);
+        final SPMMLearner<Character, Character, ?> learner =
+                new SPMMLearner<>(alphabet, spmm.getErrorOutput(), mqo, TTTAdapterMealy::new);
 
         final Experiment<SPMM<?, Character, ?, Character>> experiment = new Experiment<>(learner, eqo, alphabet);
 

api/src/main/java/de/learnlib/algorithm/LearnerConstructor.java

@@ -19,8 +19,8 @@
 import net.automatalib.alphabet.Alphabet;
 
 /**
- * A simplified view on the constructor of a {@link LearningAlgorithm}, that only requires an {@link Alphabet}
- * definition and a {@link MembershipOracle}.
+ * A simplified view on the constructor of a learning algorithm that only requires an {@link Alphabet} definition and a
+ * {@link MembershipOracle}.
  *
  * @param <L>
  *         learner type
@@ -29,7 +29,7 @@
  * @param <D>
  *         output domain type
  */
-public interface LearnerConstructor<L extends LearningAlgorithm<?, I, D>, I, D> {
+public interface LearnerConstructor<L, I, D> {
 
     /**
      * Construct the learner instance.