Github user wjsl commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/50#discussion_r44312285
--- Diff:
iterator-test-harness/src/main/java/org/apache/accumulo/iteratortest/IteratorTestUtil.java
---
@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.accumulo.iteratortest;
+
+import java.util.Objects;
+
+import org.apache.accumulo.core.data.Key;
+import org.apache.accumulo.core.data.Value;
+import org.apache.accumulo.core.iterators.SortedKeyValueIterator;
+import org.apache.accumulo.core.iterators.SortedMapIterator;
+import
org.apache.accumulo.core.iterators.system.ColumnFamilySkippingIterator;
+import org.apache.accumulo.iteratortest.testcases.IteratorTestCase;
+
+/**
+ * A collection of methods that are helpful to the development of {@link
IteratorTestCase}s.
+ */
+public class IteratorTestUtil {
+
+ public static SortedKeyValueIterator<Key,Value>
instantiateIterator(IteratorTestInput input) {
+ try {
+ return
Objects.requireNonNull(input.getIteratorClass()).newInstance();
+ } catch (InstantiationException | IllegalAccessException e) {
+ throw new RuntimeException(e);
+ }
+ }
+
+ public static SortedKeyValueIterator<Key,Value>
createSource(IteratorTestInput input) {
+ return new ColumnFamilySkippingIterator(new
SortedMapIterator(Objects.requireNonNull(input).getInput()));
--- End diff --
Might be good to make another iterator here (or wrapping the SMI) that
re-uses the Key and Value instances returned by the getters. Storing the output
of a source in a list or map without making a copy is a common pitfall.
I had a small iterator benchmark that I modified to printout the identify
of each Key and Value, and currently notice the same Value instance has the
potential to be re-used. I will try to verify if Keys exhibit the same
behavior-- I have heard anecdotes that they do.
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