From 44fc2b1069ab5295985d530ed5bc9cbd95b93cb7 Mon Sep 17 00:00:00 2001
From: Adam Richeimer <adamzr@gmail.com>
Date: Mon, 15 Sep 2014 18:15:04 -0700
Subject: [PATCH] Change ClassifierCompositeItemWriter to honor item order

The ClassifierCompositeItemWriter loops through the items passed to the
write method twice.  The first time to classifier each item.  The second
tiem to perform the actual writes (this prevents the unnecessicary IO if
an error occurs during classification).  A HashMap was previously used
to hold the classified items (key to the writer : item) however this
causes the items to be written out of order.  This update changes it to
a LinkedHashMap to honor the order the items come in.
---
 .../batch/item/support/ClassifierCompositeItemWriter.java     | 4 ++--
 .../item/support/ClassifierCompositeItemWriterTests.java      | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/ClassifierCompositeItemWriter.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/ClassifierCompositeItemWriter.java
index b8ab7e146..75a5d46d8 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/ClassifierCompositeItemWriter.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/ClassifierCompositeItemWriter.java
@@ -17,7 +17,7 @@
 package org.springframework.batch.item.support;
 
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -52,7 +52,7 @@ public class ClassifierCompositeItemWriter<T> implements ItemWriter<T> {
     @Override
 	public void write(List<? extends T> items) throws Exception {
 
-		Map<ItemWriter<? super T>, List<T>> map = new HashMap<ItemWriter<? super T>, List<T>>();
+		Map<ItemWriter<? super T>, List<T>> map = new LinkedHashMap<ItemWriter<? super T>, List<T>>();
 
 		for (T item : items) {
 			ItemWriter<? super T> key = classifier.classify(item);
diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/ClassifierCompositeItemWriterTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/ClassifierCompositeItemWriterTests.java
index de1cf6395..0405c940b 100644
--- a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/ClassifierCompositeItemWriterTests.java
+++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/ClassifierCompositeItemWriterTests.java
@@ -55,9 +55,9 @@ public class ClassifierCompositeItemWriterTests {
 		map.put("foo", fooWriter );
 		map.put("*", defaultWriter);
 		writer.setClassifier(new PatternMatchingClassifier<ItemWriter<? super String>>(map));
-		writer.write(Arrays.asList("foo", "foo", "bar"));
+		writer.write(Arrays.asList("foo", "foo", "one", "two", "three"));
 		assertEquals("[foo, foo]", foos.toString());
-		assertEquals("[bar]", defaults.toString());
+		assertEquals("[one, two, three]", defaults.toString());
 	}
 
 }