introduced iteration control for neo4j template to cover non-lazy result iteration

spring-data-neo4j/src/main/java/org/springframework/data/graph/neo4j/template/IterationController.java

@@ -0,0 +1,12 @@
+package org.springframework.data.graph.neo4j.template;
+
+/**
+* @author mh
+* @since 22.02.11
+*/
+public interface IterationController {
+    public enum IterationControl {
+        LAZY, EAGER, EAGER_STOP_ON_NULL
+    }
+    IterationControl iterateAs();
+}

spring-data-neo4j/src/main/java/org/springframework/data/graph/neo4j/template/Neo4jTemplate.java

@@ -25,8 +25,12 @@ import org.neo4j.helpers.collection.IterableWrapper;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 
+import static org.springframework.data.graph.neo4j.template.IterationController.IterationControl.EAGER_STOP_ON_NULL;
+
 public class Neo4jTemplate implements Neo4jOperations {
 
     private final GraphDatabaseService graphDatabaseService;
@@ -214,12 +218,34 @@ public class Neo4jTemplate implements Neo4jOperations {
     private <T> Iterable<T> mapPaths(final Iterable<Path> paths, final PathMapper<T> pathMapper) {
         assert paths != null;
         assert pathMapper != null;
-        return new IterableWrapper<T, Path>(paths) {
-            @Override
-            protected T underlyingObjectToObject(Path path) {
-                return pathMapper.mapPath(path);
-            }
-        };
+        IterationController.IterationControl control = getIterationControl(pathMapper);
+        switch (control) {
+            case EAGER:
+            case EAGER_STOP_ON_NULL:
+                List<T> result=new ArrayList<T>();
+                for (Path path : paths) {
+                    T mapped = pathMapper.mapPath(path);
+                    if (mapped==null && control== EAGER_STOP_ON_NULL) break;
+                    result.add(mapped);
+                }
+                return result;
+            case LAZY:
+                return new IterableWrapper<T, Path>(paths) {
+                    @Override
+                    protected T underlyingObjectToObject(Path path) {
+                        return pathMapper.mapPath(path);
+                    }
+                };
+            default: throw new IllegalStateException("Unknown IterationControl "+control);
+        }
+    }
+
+    private <T> IterationController.IterationControl getIterationControl(PathMapper<T> pathMapper) {
+        if (pathMapper instanceof IterationController) {
+            IterationController.IterationControl result = ((IterationController) pathMapper).iterateAs();
+            if (result!=null) return result;
+        }
+        return IterationController.IterationControl.LAZY;
     }
 
     @Override

spring-data-neo4j/src/main/java/org/springframework/data/graph/neo4j/template/PathMapper.java

@@ -7,9 +7,10 @@ import org.neo4j.graphdb.Path;
  * @since 19.02.11
  */
 public interface PathMapper<T> {
+
     T mapPath(Path path);
 
-    public abstract class WithoutResult implements PathMapper<Void>{
+    public abstract class WithoutResult implements PathMapper<Void>, IterationController{
         public abstract void eachPath(Path path);
 
         @Override
@@ -17,5 +18,10 @@ public interface PathMapper<T> {
             eachPath(path);
             return null;
         }
+
+        @Override
+        public IterationControl iterateAs() {
+            return IterationController.IterationControl.EAGER;
+        }
     }
 }

spring-data-neo4j/src/test/java/org/springframework/data/graph/neo4j/template/NeoTraversalTest.java

@@ -38,7 +38,7 @@ public class NeoTraversalTest extends NeoApiTest {
                 String nodeName = (String) path.endNode().getProperty("name", "");
                 resultSet.add(nodeName);
             }
-        }, Traversal.description().filter(returnAllButStartNode()).relationships(HAS));
+        }, Traversal.description().relationships(HAS).filter(returnAllButStartNode()).prune(Traversal.pruneAfterDepth(2)));
         assertEquals("all members", new HashSet<String>(asList("grandpa", "grandma", "daughter", "son", "man", "wife", "family")), resultSet);
     }