Move transaction check to superclass

src/main/java/de/maltemoeser/bcgraph/traversal/evaluator/MaximumHeightEvaluator.java

@@ -8,7 +8,7 @@
 /**
  * An evaluator rule that stops once the path's end node exceeds a certain block height.
  */
-public class MaximumHeightEvaluator implements Evaluator {
+public class MaximumHeightEvaluator extends TransactionEvaluator implements Evaluator {
 
     protected int height;
 
@@ -17,13 +17,7 @@ public MaximumHeightEvaluator(int height) {
     }
 
     @Override
-    public Evaluation evaluate(Path path) {
-        BCTransaction transaction = new BCTransaction(path.endNode());
-
-        if (!transaction.isTransaction()) {
-            throw new UnsupportedOperationException("MaximumHeightEvaluator can only be used on transaction nodes.");
-        }
-
+    public Evaluation doEvaluate(Path path) {
         if (transaction.getHeight() > height) {
             return Evaluation.EXCLUDE_AND_PRUNE;
         } else {

src/main/java/de/maltemoeser/bcgraph/traversal/evaluator/MinimumHeightEvaluator.java

@@ -1,14 +1,13 @@
 package de.maltemoeser.bcgraph.traversal.evaluator;
 
-import de.maltemoeser.bcgraph.entities.BCTransaction;
 import org.neo4j.graphdb.Path;
 import org.neo4j.graphdb.traversal.Evaluation;
 import org.neo4j.graphdb.traversal.Evaluator;
 
 /**
  * An evaluator rule that stops once the path's end node falls below a certain block height.
  */
-public class MinimumHeightEvaluator implements Evaluator {
+public class MinimumHeightEvaluator extends TransactionEvaluator implements Evaluator {
 
     protected int height;
 
@@ -17,13 +16,7 @@ public MinimumHeightEvaluator(int height) {
     }
 
     @Override
-    public Evaluation evaluate(Path path) {
-        BCTransaction transaction = new BCTransaction(path.endNode());
-
-        if (!transaction.isTransaction()) {
-            throw new UnsupportedOperationException("MinimumHeightEvaluator can only be used on transaction nodes.");
-        }
-
+    public Evaluation doEvaluate(Path path) {
         if (transaction.getHeight() < height) {
             return Evaluation.EXCLUDE_AND_PRUNE;
         } else {

src/main/java/de/maltemoeser/bcgraph/traversal/evaluator/TransactionEvaluator.java

@@ -0,0 +1,23 @@
+package de.maltemoeser.bcgraph.traversal.evaluator;
+
+import de.maltemoeser.bcgraph.entities.BCTransaction;
+import org.neo4j.graphdb.Path;
+import org.neo4j.graphdb.traversal.Evaluation;
+
+
+public abstract class TransactionEvaluator {
+
+    BCTransaction transaction;
+
+    public Evaluation evaluate(Path path) {
+        transaction = new BCTransaction(path.endNode());
+
+        if (!transaction.isTransaction()) {
+            throw new UnsupportedOperationException("A TransactionEvaluator can only be used with transaction nodes.");
+        }
+
+        return doEvaluate(path);
+    }
+
+    public abstract Evaluation doEvaluate(Path path);
+}