BATCH-2691: use constructor injection for required dependencies

Author: fmbenhassine

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/json/JsonItemReader.java

@@ -22,7 +22,6 @@
 import org.springframework.batch.item.ItemStreamReader;
 import org.springframework.batch.item.file.ResourceAwareItemReaderItemStream;
 import org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader;
-import org.springframework.beans.factory.InitializingBean;
 import org.springframework.core.io.Resource;
 import org.springframework.util.Assert;
 
@@ -50,7 +49,7 @@
  * @since 4.1
  */
 public class JsonItemReader<T> extends AbstractItemCountingItemStreamItemReader<T> implements
-		ResourceAwareItemReaderItemStream<T>, InitializingBean {
+		ResourceAwareItemReaderItemStream<T> {
 
 	private static final Log LOGGER = LogFactory.getLog(JsonItemReader.class);
 
@@ -60,6 +59,18 @@ public class JsonItemReader<T> extends AbstractItemCountingItemStreamItemReader<
 
 	private boolean strict = true;
 
+	/**
+	 * Create a new {@link JsonItemReader} instance.
+	 * @param resource the input json resource
+	 * @param jsonObjectReader the json object reader to use
+	 */
+	public JsonItemReader(Resource resource, JsonObjectReader<T> jsonObjectReader) {
+		Assert.notNull(resource, "The resource must not be null.");
+		Assert.notNull(jsonObjectReader, "The json object reader must not be null.");
+		this.resource = resource;
+		this.jsonObjectReader = jsonObjectReader;
+	}
+
 	/**
 	 * Set the {@link JsonObjectReader} to use to read and map Json fragments to domain objects.
 	 * @param jsonObjectReader the json object reader to use
@@ -112,10 +123,4 @@ protected void doClose() throws Exception {
 		this.jsonObjectReader.close();
 	}
 
-	@Override
-	public void afterPropertiesSet() throws Exception {
-		Assert.notNull(this.jsonObjectReader, "The json object reader must not be null.");
-		Assert.notNull(this.resource, "The resource must not be null.");
-	}
-
 }

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/json/builder/JsonItemReaderBuilder.java

@@ -145,9 +145,7 @@ public JsonItemReader<T> build() {
 			Assert.state(StringUtils.hasText(this.name), "A name is required when saveState is set to true.");
 		}
 
-		JsonItemReader<T> reader = new JsonItemReader<>();
-		reader.setJsonObjectReader(this.jsonObjectReader);
-		reader.setResource(this.resource);
+		JsonItemReader<T> reader = new JsonItemReader<>(this.resource, this.jsonObjectReader);
 		reader.setName(this.name);
 		reader.setStrict(this.strict);
 		reader.setSaveState(this.saveState);

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/json/JsonItemReaderCommonTests.java

@@ -38,21 +38,18 @@ public abstract class JsonItemReaderCommonTests extends AbstractItemStreamItemRe
 	protected abstract JsonObjectReader<Foo> getJsonObjectReader();
 
 	@Override
-	protected ItemReader<Foo> getItemReader() throws Exception {
-		JsonItemReader<Foo> itemReader = new JsonItemReader<>();
-		itemReader.setResource(new ByteArrayResource(FOOS.getBytes()));
+	protected ItemReader<Foo> getItemReader() {
+		ByteArrayResource resource = new ByteArrayResource(FOOS.getBytes());
+		JsonObjectReader<Foo> jsonObjectReader = getJsonObjectReader();
+		JsonItemReader<Foo> itemReader = new JsonItemReader<>(resource, jsonObjectReader);
 		itemReader.setName("fooJsonItemReader");
-		itemReader.setSaveState(true);
-		itemReader.setJsonObjectReader(getJsonObjectReader());
-		itemReader.afterPropertiesSet();
 		return itemReader;
 	}
 
 	@Override
-	protected void pointToEmptyInput(ItemReader<Foo> tested) throws Exception {
+	protected void pointToEmptyInput(ItemReader<Foo> tested) {
 		JsonItemReader<Foo> reader = (JsonItemReader<Foo>) tested;
 		reader.setResource(new ByteArrayResource("[]".getBytes()));
-		reader.afterPropertiesSet();
 
 		reader.open(new ExecutionContext());
 	}

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/json/JsonItemReaderTests.java

@@ -22,60 +22,77 @@
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
 
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.core.io.AbstractResource;
+import org.springframework.core.io.ByteArrayResource;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 
 /**
  * @author Mahmoud Ben Hassine
  */
+@RunWith(MockitoJUnitRunner.class)
 public class JsonItemReaderTests {
 
 	@Rule
 	public ExpectedException expectedException = ExpectedException.none();
 
-	private JsonItemReader<String> itemReader = new JsonItemReader<>();
-
-	@Test
-	public void testMandatoryJsonObjectReader() throws Exception {
-		this.expectedException.expect(IllegalArgumentException.class);
-		this.expectedException.expectMessage("The json object reader must not be null.");
+	@Mock
+	private JsonObjectReader<String> jsonObjectReader;
 
-		this.itemReader.afterPropertiesSet();
-	}
+	private JsonItemReader<String> itemReader;
 
 	@Test
-	public void testMandatoryResource() throws Exception {
-		this.expectedException.expect(IllegalArgumentException.class);
-		this.expectedException.expectMessage("The resource must not be null.");
-		this.itemReader.setJsonObjectReader(() -> null);
+	public void testValidation() {
+		try {
+			new JsonItemReader<>(null, this.jsonObjectReader);
+			fail("A resource is required.");
+		} catch (IllegalArgumentException iae) {
+			assertEquals("The resource must not be null.", iae.getMessage());
+		}
 
-		this.itemReader.afterPropertiesSet();
+		try {
+			new JsonItemReader<>(new ByteArrayResource("[{}]".getBytes()), null);
+			fail("A json object reader is required.");
+		} catch (IllegalArgumentException iae) {
+			assertEquals("The json object reader must not be null.", iae.getMessage());
+		}
 	}
 
 	@Test
-	public void testNonExistentResource() throws Exception {
+	public void testNonExistentResource() {
+		// given
 		this.expectedException.expect(ItemStreamException.class);
 		this.expectedException.expectMessage("Failed to initialize the reader");
 		this.expectedException.expectCause(Matchers.instanceOf(IllegalStateException.class));
-		this.itemReader.setJsonObjectReader(() -> null);
-		this.itemReader.setResource(new NonExistentResource());
-		this.itemReader.afterPropertiesSet();
+		this.itemReader = new JsonItemReader<>(new NonExistentResource(), this.jsonObjectReader);
 
+		// when
 		this.itemReader.open(new ExecutionContext());
+
+		// then
+		// expected exception
 	}
 
 	@Test
-	public void testNonReadableResource() throws Exception {
+	public void testNonReadableResource() {
+		// given
 		this.expectedException.expect(ItemStreamException.class);
 		this.expectedException.expectMessage("Failed to initialize the reader");
 		this.expectedException.expectCause(Matchers.instanceOf(IllegalStateException.class));
-		this.itemReader.setJsonObjectReader(() -> null);
-		this.itemReader.setResource(new NonReadableResource());
-		this.itemReader.afterPropertiesSet();
+		this.itemReader = new JsonItemReader<>(new NonReadableResource(), this.jsonObjectReader);
 
+		// when
 		this.itemReader.open(new ExecutionContext());
+
+		// then
+		// expected exception
 	}
 
 	private static class NonExistentResource extends AbstractResource {