bugfix AqlExecutionExplainEntity indexes

Author: michele

src/main/java/com/arangodb/entity/AqlExecutionExplainEntity.java

@@ -82,7 +82,7 @@ public static class ExecutionNode {
 		private Boolean isConst;
 		private Boolean canThrow;
 		private String expressionType;
-		private IndexEntity indexes;
+        private Collection<IndexEntity> indexes;
 		private ExecutionExpression expression;
 		private ExecutionCollection condition;
 		private Boolean reverse;
@@ -163,7 +163,7 @@ public String getExpressionType() {
 			return expressionType;
 		}
 
-		public IndexEntity getIndexes() {
+        public Collection<IndexEntity> getIndexes() {
 			return indexes;
 		}
 

src/test/java/com/arangodb/ArangoDatabaseTest.java

@@ -913,6 +913,34 @@ public void explainQuery() {
         assertThat(plan.getNodes().size(), is(greaterThan(0)));
     }
 
+    @Test
+    public void explainQueryWithIndexNode() {
+        ArangoCollection character = db.collection("got_characters");
+        ArangoCollection actor = db.collection("got_actors");
+
+        if (!character.exists())
+            character.create();
+
+        if (!actor.exists())
+            actor.create();
+
+        String query = "" +
+                "FOR `character` IN `got_characters` " +
+                "   FOR `actor` IN `got_actors` " +
+                "       FILTER `character`.`actor` == `actor`.`_id` " +
+                "       RETURN `character`";
+
+        final ExecutionPlan plan = db.explainQuery(query, null, null).getPlan();
+        plan.getNodes().stream()
+                .filter(it -> "IndexNode".equals(it.getType()))
+                .flatMap(it -> it.getIndexes().stream())
+                .forEach(it -> {
+                    assertThat(it.getType(), is(IndexType.primary));
+                    assertThat(it.getSelectivityEstimate(), is(1.0));
+                    assertThat(it.getFields(), contains("_key"));
+                });
+    }
+
     @Test
     public void parseQuery() {
         final AqlParseEntity parse = arangoDB.db().parseQuery("for i in 1..1 return i");