diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/builder/SingleItemPeekableItemReaderBuilder.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/builder/SingleItemPeekableItemReaderBuilder.java new file mode 100644 index 000000000..347b92bc7 --- /dev/null +++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/builder/SingleItemPeekableItemReaderBuilder.java @@ -0,0 +1,61 @@ +/* + * Copyright 2017 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 + * + * http://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.item.support.builder; + +import org.springframework.batch.item.ItemReader; +import org.springframework.batch.item.support.SingleItemPeekableItemReader; +import org.springframework.util.Assert; + +/** + * Creates a fully qualified SingleItemPeekeableItemReader. + * + * @author Glenn Renfro + * + * @since 4.0 + */ +public class SingleItemPeekableItemReaderBuilder { + + private ItemReader delegate; + + /** + * The item reader to use as a delegate. Items are read from the delegate and passed + * to the caller in + * {@link org.springframework.batch.item.support.SingleItemPeekableItemReader#read()}. + * + * @param delegate the delegate to set + * @return this instance for method chaining + * @see SingleItemPeekableItemReader#setDelegate(ItemReader) + */ + public SingleItemPeekableItemReaderBuilder delegate(ItemReader delegate) { + this.delegate = delegate; + + return this; + } + + /** + * Returns a fully constructed {@link SingleItemPeekableItemReader}. + * + * @return a new {@link SingleItemPeekableItemReader} + */ + public SingleItemPeekableItemReader build() { + Assert.notNull(this.delegate, "A delegate is required"); + + SingleItemPeekableItemReader reader = new SingleItemPeekableItemReader<>(); + reader.setDelegate(this.delegate); + return reader; + } +} diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/builder/SingleItemPeekableItemReaderBuilderTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/builder/SingleItemPeekableItemReaderBuilderTests.java new file mode 100644 index 000000000..31fd147f6 --- /dev/null +++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/builder/SingleItemPeekableItemReaderBuilderTests.java @@ -0,0 +1,68 @@ +/* + * Copyright 2017 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 + * + * http://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.item.support.builder; + +import java.util.Arrays; + +import org.junit.Test; + +import org.springframework.batch.item.sample.Foo; +import org.springframework.batch.item.support.ListItemReader; +import org.springframework.batch.item.support.SingleItemPeekableItemReader; + +import static org.junit.Assert.assertEquals; +import static org.junit.Assert.fail; + +/** + * @author Glenn Renfro + */ +public class SingleItemPeekableItemReaderBuilderTests { + + /** + * Test method to validate builder creates a + * {@link org.springframework.batch.item.support.SingleItemPeekableItemReader#peek()} + * with expected peek and read behavior. + */ + @Test + public void testPeek() throws Exception { + SingleItemPeekableItemReader reader = new SingleItemPeekableItemReaderBuilder() + .delegate( + new ListItemReader(Arrays.asList("a", "b"))) + .build(); + assertEquals("a", reader.peek()); + assertEquals("a", reader.read()); + assertEquals("b", reader.read()); + assertEquals(null, reader.peek()); + assertEquals(null, reader.read()); + } + + /** + * Test method to validate that an {@link IllegalArgumentException} is thrown if the + * delegate is not set in the builder. + */ + @Test + public void testValidation() { + try { + new SingleItemPeekableItemReaderBuilder().build(); + fail("A delegate is required"); + } + catch (IllegalArgumentException iae) { + assertEquals("A delegate is required", iae.getMessage()); + } + } + +}