Removed redundant logical checks from MongoItemReaderBuilder and MongoItemReader

to prevent false alarm for not providing the limit for query or pagesize for the reader

Issue #3673

Author: parikshitdutta

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

@@ -79,6 +79,7 @@
  * @author Michael Minella
  * @author Takaaki Iida
  * @author Mahmoud Ben Hassine
+ * @author Parikshit Dutta
  */
 public class MongoItemReader<T> extends AbstractPaginatedDataItemReader<T> implements InitializingBean {
 
@@ -241,10 +242,6 @@ public void afterPropertiesSet() throws Exception {
 		if (queryString != null) {
 			Assert.state(sort != null, "A sort is required.");
 		}
-
-		if (query != null && query.getLimit() != 0) {
-			log.warn("PageSize in Query object was ignored. Please set it by MongoItemReader.setPageSize().");
-		}
 	}
 
 	private String replacePlaceholders(String input, List<Object> values) {

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

@@ -34,6 +34,7 @@
  * @author Glenn Renfro
  * @author Mahmoud Ben Hassine
  * @author Drummond Dawson
+ * @author Parikshit Dutta
  * @since 4.0
  * @see MongoItemReader
  */
@@ -286,9 +287,6 @@ public MongoItemReader<T> build() {
 		if(StringUtils.hasText(this.jsonQuery)) {
 			Assert.notNull(this.sorts, "sorts map is required.");
 		}
-		else {
-			Assert.state(this.query.getLimit() != 0, "PageSize in Query object was ignored.");
-		}
 
 		MongoItemReader<T> reader = new MongoItemReader<>();
 		reader.setTemplate(this.template);

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2018 the original author or authors.
+ * Copyright 2013-2020 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.
@@ -38,6 +38,10 @@
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.when;
 
+/**
+ * @author Michael Minella
+ * @author Parikshit Dutta
+ */
 public class MongoItemReaderTests {
 
 	private MongoItemReader<String> reader;
@@ -310,7 +314,46 @@ public void testQueryObjectWithPageSize() throws Exception {
 		assertEquals(100, actualQuery.getLimit());
 		assertEquals(0, actualQuery.getSkip());
 	}
-	
+
+	@Test
+	public void testQueryObjectWithoutLimit() throws Exception {
+		reader = new MongoItemReader<>();
+		reader.setTemplate(template);
+
+		reader.setQuery(new Query());
+		reader.setTargetType(String.class);
+		reader.setPageSize(100);
+
+		reader.afterPropertiesSet();
+
+		ArgumentCaptor<Query> queryContainer = ArgumentCaptor.forClass(Query.class);
+		when(template.find(queryContainer.capture(), eq(String.class))).thenReturn(new ArrayList<>());
+
+		assertFalse(reader.doPageRead().hasNext());
+
+		Query actualQuery = queryContainer.getValue();
+		assertEquals(100, actualQuery.getLimit());
+	}
+
+	@Test
+	public void testQueryObjectWithoutLimitAndPageSize() throws Exception {
+		reader = new MongoItemReader<>();
+		reader.setTemplate(template);
+
+		reader.setQuery(new Query());
+		reader.setTargetType(String.class);
+
+		reader.afterPropertiesSet();
+
+		ArgumentCaptor<Query> queryContainer = ArgumentCaptor.forClass(Query.class);
+		when(template.find(queryContainer.capture(), eq(String.class))).thenReturn(new ArrayList<>());
+
+		assertFalse(reader.doPageRead().hasNext());
+
+		Query actualQuery = queryContainer.getValue();
+		assertEquals(10, actualQuery.getLimit());
+	}
+
 	@Test
 	public void testQueryObjectWithCollection() throws Exception {
 		reader = new MongoItemReader<>();

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2018 the original author or authors.
+ * Copyright 2017-2020 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.
@@ -41,6 +41,7 @@
 /**
  * @author Glenn Renfro
  * @author Drummond Dawson
+ * @author Parikshit Dutta
  */
 public class MongoItemReaderBuilderTests {
 	@Mock
@@ -145,6 +146,41 @@ public void testVarargs() throws Exception {
 		assertEquals("collection", collectionContainer.getValue());
 	}
 
+	@Test
+	public void testWithoutQueryLimit() throws Exception {
+		MongoItemReader<String> reader = new MongoItemReaderBuilder<String>().template(this.template)
+				.targetType(String.class)
+				.query(new Query())
+				.sorts(this.sortOptions)
+				.name("mongoReaderTest")
+				.pageSize(50)
+				.build();
+
+		when(template.find(this.queryContainer.capture(), eq(String.class))).thenReturn(new ArrayList<>());
+
+		assertNull("reader should not return result", reader.read());
+
+		Query query = this.queryContainer.getValue();
+		assertEquals(50, query.getLimit());
+	}
+
+	@Test
+	public void testWithoutQueryLimitAndPageSize() throws Exception {
+		MongoItemReader<String> reader = new MongoItemReaderBuilder<String>().template(this.template)
+				.targetType(String.class)
+				.query(new Query())
+				.sorts(this.sortOptions)
+				.name("mongoReaderTest")
+				.build();
+
+		when(template.find(this.queryContainer.capture(), eq(String.class))).thenReturn(new ArrayList<>());
+
+		assertNull("reader should not return result", reader.read());
+
+		Query query = this.queryContainer.getValue();
+		assertEquals(10, query.getLimit());
+	}
+
 	@Test
 	public void testNullTemplate() {
 		validateExceptionMessage(new MongoItemReaderBuilder<String>().targetType(String.class)