Add state reset on close of AbstractPaginatedDataItemReader

Resolves #1086

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/data/AbstractPaginatedDataItemReader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2023 the original author or authors.
+ * Copyright 2013-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -103,6 +103,14 @@ public abstract class AbstractPaginatedDataItemReader<T> extends AbstractItemCou
 
 	@Override
 	protected void doClose() throws Exception {
+		this.lock.lock();
+		try {
+			this.page = 0;
+			this.results = null;
+		}
+		finally {
+			this.lock.unlock();
+		}
 	}
 
 	@Override

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/MongoPagingItemReaderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2023 the original author or authors.
+ * Copyright 2013-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.batch.item.data;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -34,6 +35,7 @@ import org.springframework.data.mongodb.core.query.Query;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
@@ -347,4 +349,18 @@ class MongoPagingItemReaderTests {
 			.withMessage("Sorts must not be null");
 	}
 
+	@Test
+	void testClose() throws Exception {
+		// given
+		when(template.find(any(), any())).thenReturn(List.of("string"));
+		reader.read();
+
+		// when
+		reader.close();
+
+		// then
+		assertEquals(0, reader.page);
+		assertNull(reader.results);
+	}
+
 }