diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/IteratorItemReader.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/IteratorItemReader.java new file mode 100644 index 000000000..958bfbd44 --- /dev/null +++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/IteratorItemReader.java @@ -0,0 +1,73 @@ +/* + * Copyright 2006-2007 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; + +import java.util.Iterator; + +import org.springframework.batch.item.ItemReader; +import org.springframework.batch.item.ParseException; +import org.springframework.batch.item.UnexpectedInputException; +import org.springframework.util.Assert; + +/** + * An {@link ItemReader} that pulls data from a {@link Iterator} or + * {@link Iterable} using the constructors. + * + * @author Juliusz Brzostek + * @author Dave Syer + */ +public class IteratorItemReader implements ItemReader { + + /** + * Internal iterator + */ + private final Iterator iterator; + + /** + * Construct a new reader from this iterable (could be a collection), by + * extracting an instance of {@link Iterator} from it. + * + * @param iterable in instance of {@link Iterable} + * + * @see Iterable#iterator() + */ + public IteratorItemReader(Iterable iterable) { + Assert.notNull(iterable, "Iterable argument cannot be null!"); + this.iterator = iterable.iterator(); + } + + /** + * Construct a new reader from this iterator directly. + * @param iterator an instance of {@link Iterator} + */ + public IteratorItemReader(Iterator iterator) { + Assert.notNull(iterator, "Iterator argument cannot be null!"); + this.iterator = iterator; + } + + /** + * Implementation of {@link ItemReader#read()} that just iterates over the + * iterator provided. + */ + public T read() throws Exception, UnexpectedInputException, ParseException { + if (iterator.hasNext()) + return iterator.next(); + else + return null; // end of data + } + +} diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/IteratorItemReaderTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/IteratorItemReaderTests.java new file mode 100644 index 000000000..50ce249ea --- /dev/null +++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/IteratorItemReaderTests.java @@ -0,0 +1,41 @@ +/* + * Copyright 2006-2007 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; + +import java.util.Arrays; + +import junit.framework.TestCase; + +public class IteratorItemReaderTests extends TestCase{ + + public void testIterable() throws Exception { + IteratorItemReader reader = new IteratorItemReader(Arrays.asList(new String[] { "a", "b", "c" })); + assertEquals("a", reader.read()); + assertEquals("b", reader.read()); + assertEquals("c", reader.read()); + assertEquals(null, reader.read()); + } + + public void testIterator() throws Exception { + IteratorItemReader reader = new IteratorItemReader(Arrays.asList(new String[] { "a", "b", "c" }).iterator()); + assertEquals("a", reader.read()); + assertEquals("b", reader.read()); + assertEquals("c", reader.read()); + assertEquals(null, reader.read()); + } + +}