Change visibility of properties to protected in JdbcPagingItemReaderBuilder

There are cases, when you want to extend the JdbcPagingItemReader
by adding some custom fields and behaviours, but want to stay in
the normal way of creating this class via a Builder class.

If you want to do it, you currently have to reimplement the whole
class just for adding some fields because there is no non-ugly way
to access the fields. This commit makes those properties protected,
so one can override the default build() method behaviour in the
derived class and still have access to the properties.

Issue #4331

Author: Ditscheridou

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/database/builder/JdbcPagingItemReaderBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2022 the original author or authors.
+ * Copyright 2017-2023 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.
@@ -56,33 +56,33 @@
  */
 public class JdbcPagingItemReaderBuilder<T> {
 
-	private DataSource dataSource;
+	protected DataSource dataSource;
 
-	private int fetchSize = JdbcPagingItemReader.VALUE_NOT_SET;
+	protected int fetchSize = JdbcPagingItemReader.VALUE_NOT_SET;
 
-	private PagingQueryProvider queryProvider;
+	protected PagingQueryProvider queryProvider;
 
-	private RowMapper<T> rowMapper;
+	protected RowMapper<T> rowMapper;
 
-	private Map<String, Object> parameterValues;
+	protected Map<String, Object> parameterValues;
 
-	private int pageSize = 10;
+	protected int pageSize = 10;
 
-	private String groupClause;
+	protected String groupClause;
 
-	private String selectClause;
+	protected String selectClause;
 
-	private String fromClause;
+	protected String fromClause;
 
-	private String whereClause;
+	protected String whereClause;
 
-	private Map<String, Order> sortKeys;
+	protected Map<String, Order> sortKeys;
 
-	private boolean saveState = true;
+	protected boolean saveState = true;
 
-	private String name;
+	protected String name;
 
-	private int maxItemCount = Integer.MAX_VALUE;
+	protected int maxItemCount = Integer.MAX_VALUE;
 
 	private int currentItemCount;
 
@@ -329,7 +329,7 @@ public JdbcPagingItemReader<T> build() {
 		return reader;
 	}
 
-	private PagingQueryProvider determineQueryProvider(DataSource dataSource) {
+	protected PagingQueryProvider determineQueryProvider(DataSource dataSource) {
 
 		try {
 			DatabaseType databaseType = DatabaseType.fromMetaData(dataSource);
@@ -394,5 +394,4 @@ private PagingQueryProvider determineQueryProvider(DataSource dataSource) {
 			throw new IllegalArgumentException("Unable to determine PagingQueryProvider type", e);
 		}
 	}
-
 }