Fix SimpleBinaryBufferedReaderFactory for longer endings

Resolves #811

Author: hpoettker

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/SimpleBinaryBufferedReaderFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2023 the original author or authors.
+ * Copyright 2006-2024 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.
@@ -123,25 +123,24 @@ private boolean isEndOfLine(StringBuilder buffer, StringBuilder candidate, int n
 			}
 
 			char c = (char) next;
-			if (ending.charAt(0) == c || candidate.length() > 0) {
+			if (ending.charAt(0) == c || !candidate.isEmpty()) {
 				candidate.append(c);
 			}
-
-			if (candidate.length() == 0) {
+			else {
 				buffer.append(c);
 				return false;
 			}
 
-			boolean end = ending.equals(candidate.toString());
-			if (end) {
+			if (ending.contentEquals(candidate)) {
 				candidate.delete(0, candidate.length());
+				return true;
 			}
-			else if (candidate.length() >= ending.length()) {
-				buffer.append(candidate);
-				candidate.delete(0, candidate.length());
+			while (!ending.startsWith(candidate.toString())) {
+				buffer.append(candidate.charAt(0));
+				candidate.delete(0, 1);
 			}
 
-			return end;
+			return false;
 
 		}
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/SimpleBinaryBufferedReaderFactoryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2022 the original author or authors.
+ * Copyright 2006-2024 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.
@@ -21,6 +21,8 @@
 import java.io.BufferedReader;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.springframework.core.io.ByteArrayResource;
 
 /**
@@ -75,16 +77,27 @@ void testCreateWithLineEndingAtEnd() throws Exception {
 		assertNull(reader.readLine());
 	}
 
-	@Test
-	void testCreateWithFalseLineEnding() throws Exception {
+	@ParameterizedTest
+	@ValueSource(strings = { "||", "|||" })
+	void testCreateWithFalseLineEnding(String lineEnding) throws Exception {
 		SimpleBinaryBufferedReaderFactory factory = new SimpleBinaryBufferedReaderFactory();
-		factory.setLineEnding("||");
+		factory.setLineEnding(lineEnding);
 		@SuppressWarnings("resource")
-		BufferedReader reader = factory.create(new ByteArrayResource("a|b||".getBytes()), "UTF-8");
+		BufferedReader reader = factory.create(new ByteArrayResource(("a|b" + lineEnding).getBytes()), "UTF-8");
 		assertEquals("a|b", reader.readLine());
 		assertNull(reader.readLine());
 	}
 
+	@Test
+	void testCreateWithFalseMixedCharacterLineEnding() throws Exception {
+		SimpleBinaryBufferedReaderFactory factory = new SimpleBinaryBufferedReaderFactory();
+		factory.setLineEnding("#@");
+		@SuppressWarnings("resource")
+		BufferedReader reader = factory.create(new ByteArrayResource(("a##@").getBytes()), "UTF-8");
+		assertEquals("a#", reader.readLine());
+		assertNull(reader.readLine());
+	}
+
 	@Test
 	void testCreateWithIncompleteLineEnding() throws Exception {
 		SimpleBinaryBufferedReaderFactory factory = new SimpleBinaryBufferedReaderFactory();