Add ResourcesItemReaderBuilder with support for a file pattern

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

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2026 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.
+ *  You may obtain a copy of the License at
+ *
+ *          https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.springframework.batch.infrastructure.item.file.builder;
+
+import java.io.IOException;
+
+import org.jspecify.annotations.Nullable;
+
+import org.springframework.batch.infrastructure.item.ExecutionContext;
+import org.springframework.batch.infrastructure.item.ItemStreamSupport;
+import org.springframework.batch.infrastructure.item.file.ResourcesItemReader;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
+import org.springframework.core.io.support.ResourcePatternResolver;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * A builder implementation for the {@link ResourcesItemReader}.
+ *
+ * @author Sanghyuk Jung
+ * @since 6.1
+ * @see ResourcesItemReader
+ */
+public class ResourcesItemReaderBuilder {
+
+	private Resource @Nullable [] resources;
+
+	private @Nullable String filesPattern;
+
+	private @Nullable String name;
+
+	/**
+	 * The name used to calculate the key within the {@link ExecutionContext}.
+	 * @param name name of the reader instance
+	 * @return this instance for method chaining.
+	 * @see ItemStreamSupport#setName(String)
+	 */
+	public ResourcesItemReaderBuilder name(String name) {
+		this.name = name;
+
+		return this;
+	}
+
+	/**
+	 * The array of resources that the {@link ResourcesItemReader} will serve up as items.
+	 * @param resources the array of resources to use.
+	 * @return this instance for method chaining.
+	 * @see ResourcesItemReader#setResources(Resource[])
+	 */
+	public ResourcesItemReaderBuilder resources(Resource... resources) {
+		this.resources = resources;
+
+		return this;
+	}
+
+	/**
+	 * The location pattern of files that the {@link ResourcesItemReader} will serve up as
+	 * items. This is an Ant-style pattern that supports wildcards like `*`, `**` and
+	 * `?`(for example `/data/*.csv`or `data/**\/user?.txt`).
+	 * @param filesPattern the location pattern of files to use.
+	 * @return this instance for method chaining.
+	 */
+	public ResourcesItemReaderBuilder filesPattern(String filesPattern) {
+		this.filesPattern = filesPattern;
+
+		return this;
+	}
+
+	/**
+	 * Builds the {@link ResourcesItemReader}.
+	 * @return a {@link ResourcesItemReader}
+	 */
+	public ResourcesItemReader build() {
+		Assert.isTrue(this.resources != null || this.filesPattern != null,
+				"resources array or filesPattern is required.");
+
+		ResourcesItemReader reader = new ResourcesItemReader();
+
+		if (this.resources != null) {
+			reader.setResources(this.resources);
+		}
+		else if (this.filesPattern != null) {
+			ResourcePatternResolver patternResolver = new PathMatchingResourcePatternResolver();
+			try {
+				Resource[] resources = patternResolver.getResources("file:" + this.filesPattern);
+				reader.setResources(resources);
+			}
+			catch (IOException e) {
+				throw new IllegalArgumentException("Unable to initialize resources by the pattern " + this.filesPattern,
+						e);
+			}
+		}
+
+		if (StringUtils.hasText(this.name)) {
+			reader.setName(this.name);
+		}
+
+		return reader;
+	}
+
+}

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

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2026 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.
+ *  You may obtain a copy of the License at
+ *
+ *          https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.springframework.batch.infrastructure.item.file.builder;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.infrastructure.item.ExecutionContext;
+import org.springframework.batch.infrastructure.item.file.ResourcesItemReader;
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+/**
+ * @author Sanghyuk Jung
+ */
+class ResourcesItemReaderBuilderTests {
+
+	@Test
+	void testResources() throws Exception {
+		Resource resource1 = new ByteArrayResource("foo".getBytes());
+		Resource resource2 = new ByteArrayResource("bar".getBytes());
+
+		ResourcesItemReader reader = new ResourcesItemReaderBuilder().resources(resource1, resource2)
+			.name("resourcesReader")
+			.build();
+
+		reader.open(new ExecutionContext());
+		assertEquals(resource1, reader.read());
+		assertEquals(resource2, reader.read());
+		assertNull(reader.read());
+		reader.close();
+	}
+
+	@Test
+	void testFilesPattern() throws Exception {
+		String basePath = new ClassPathResource("", this.getClass()).getFile().getPath();
+
+		ResourcesItemReader reader = new ResourcesItemReaderBuilder().filesPattern(basePath + "/resource?.txt")
+			.name("resourcesReader")
+			.build();
+
+		reader.open(new ExecutionContext());
+		Set<String> fileNames = new HashSet<>();
+		for (Resource resource = reader.read(); resource != null; resource = reader.read()) {
+			fileNames.add(resource.getFilename());
+		}
+		assertEquals(Set.of("resource1.txt", "resource2.txt"), fileNames);
+		reader.close();
+	}
+
+	@Test
+	void testName() throws Exception {
+		ResourcesItemReader reader = new ResourcesItemReaderBuilder().resources(new ByteArrayResource("foo".getBytes()))
+			.name("fooReader")
+			.build();
+
+		reader.open(new ExecutionContext());
+		reader.read();
+		ExecutionContext executionContext = new ExecutionContext();
+		reader.update(executionContext);
+		assertEquals(1, executionContext.getInt("fooReader.COUNT"));
+		reader.close();
+	}
+
+	@Test
+	void testMissingResourcesAndFilesPattern() {
+		Exception exception = assertThrows(IllegalArgumentException.class,
+				() -> new ResourcesItemReaderBuilder().build());
+		assertEquals("resources array or filesPattern is required.", exception.getMessage());
+	}
+
+}

spring-batch-infrastructure/src/test/resources/org/springframework/batch/infrastructure/item/file/builder/resource1.txt

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+1

spring-batch-infrastructure/src/test/resources/org/springframework/batch/infrastructure/item/file/builder/resource2.txt

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+2