DATACMNS-333 - Added Jackson 2 support to repository populators.

Added necessary infrastructure to use Jackson 2 with repository populators. Expose a jackson2-populator XML element in the namespace to setup a Jackson2 based repository populator.

src/main/java/org/springframework/data/repository/config/RepositoryNameSpaceHandler.java

@@ -36,5 +36,6 @@ public class RepositoryNameSpaceHandler extends NamespaceHandlerSupport {
 	public void init() {
 		registerBeanDefinitionParser("unmarshaller-populator", PARSER);
 		registerBeanDefinitionParser("jackson-populator", PARSER);
+		registerBeanDefinitionParser("jackson2-populator", PARSER);
 	}
 }

src/main/java/org/springframework/data/repository/config/ResourceReaderRepositoryPopulatorBeanDefinitionParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 the original author or authors.
+ * Copyright 2012-2013 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.
@@ -15,9 +15,12 @@
  */
 package org.springframework.data.repository.config;
 
+import java.util.Arrays;
+
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
+import org.springframework.data.repository.init.Jackson2RepositoryPopulatorFactoryBean;
 import org.springframework.data.repository.init.JacksonRepositoryPopulatorFactoryBean;
 import org.springframework.data.repository.init.UnmarshallerRepositoryPopulatorFactoryBean;
 import org.springframework.util.StringUtils;
@@ -38,8 +41,16 @@ public class ResourceReaderRepositoryPopulatorBeanDefinitionParser extends Abstr
 	protected String getBeanClassName(Element element) {
 
 		String name = element.getLocalName();
-		return "unmarshaller-populator".equals(name) ? UnmarshallerRepositoryPopulatorFactoryBean.class.getName()
-				: JacksonRepositoryPopulatorFactoryBean.class.getName();
+
+		if ("unmarshaller-populator".equals(name)) {
+			return UnmarshallerRepositoryPopulatorFactoryBean.class.getName();
+		} else if ("jackson-populator".equals(name)) {
+			return JacksonRepositoryPopulatorFactoryBean.class.getName();
+		} else if ("jackson2-populator".equals(name)) {
+			return Jackson2RepositoryPopulatorFactoryBean.class.getName();
+		}
+
+		throw new IllegalStateException("Unsupported populator type " + name + "!");
 	}
 
 	/*
@@ -55,7 +66,7 @@ public class ResourceReaderRepositoryPopulatorBeanDefinitionParser extends Abstr
 
 		if ("unmarshaller-populator".equals(localName)) {
 			parseXmlPopulator(element, builder);
-		} else if ("jackson-populator".equals(localName)) {
+		} else if (Arrays.asList("jackson-populator", "jackson2-populator").contains(localName)) {
 			parseJsonPopulator(element, builder);
 		}
 	}
@@ -66,7 +77,7 @@ public class ResourceReaderRepositoryPopulatorBeanDefinitionParser extends Abstr
 	 * @param element
 	 * @param builder
 	 */
-	private void parseJsonPopulator(Element element, BeanDefinitionBuilder builder) {
+	private static void parseJsonPopulator(Element element, BeanDefinitionBuilder builder) {
 
 		String objectMapperRef = element.getAttribute("object-mapper-ref");
 
@@ -81,7 +92,7 @@ public class ResourceReaderRepositoryPopulatorBeanDefinitionParser extends Abstr
 	 * @param element
 	 * @param builder
 	 */
-	private void parseXmlPopulator(Element element, BeanDefinitionBuilder builder) {
+	private static void parseXmlPopulator(Element element, BeanDefinitionBuilder builder) {
 
 		String unmarshallerRefName = element.getAttribute("unmarshaller-ref");
 

src/main/java/org/springframework/data/repository/init/Jackson2RepositoryPopulatorFactoryBean.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2013 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.data.repository.init;
+
+import org.springframework.beans.factory.FactoryBean;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+/**
+ * {@link FactoryBean} to set up a {@link ResourceReaderRepositoryPopulator} with a {@link Jackson2ResourceReader}.
+ * 
+ * @author Oliver Gierke
+ * @since 1.6
+ */
+public class Jackson2RepositoryPopulatorFactoryBean extends AbstractRepositoryPopulatorFactoryBean {
+
+	private ObjectMapper mapper;
+
+	/**
+	 * Configures the {@link ObjectMapper} to be used.
+	 * 
+	 * @param mapper
+	 */
+	public void setMapper(ObjectMapper mapper) {
+		this.mapper = mapper;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.init.AbstractRepositoryPopulatorFactoryBean#getResourceReader()
+	 */
+	@Override
+	protected ResourceReader getResourceReader() {
+		return new Jackson2ResourceReader(mapper);
+	}
+}

src/main/java/org/springframework/data/repository/init/Jackson2ResourceReader.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2013 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.data.repository.init;
+
+import static com.fasterxml.jackson.databind.DeserializationFeature.*;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import org.springframework.core.io.Resource;
+import org.springframework.util.ClassUtils;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+/**
+ * A {@link ResourceReader} using Jackson to read JSON into objects.
+ * 
+ * @author Oliver Gierke
+ * @since 1.6
+ */
+public class Jackson2ResourceReader implements ResourceReader {
+
+	private static final String DEFAULT_TYPE_KEY = "_class";
+	private static final ObjectMapper DEFAULT_MAPPER = new ObjectMapper();
+
+	static {
+		DEFAULT_MAPPER.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);
+	}
+
+	private final ObjectMapper mapper;
+	private String typeKey = DEFAULT_TYPE_KEY;
+
+	/**
+	 * Creates a new {@link Jackson2ResourceReader}.
+	 */
+	public Jackson2ResourceReader() {
+		this(DEFAULT_MAPPER);
+	}
+
+	/**
+	 * Creates a new {@link Jackson2ResourceReader} using the given {@link ObjectMapper}.
+	 * 
+	 * @param mapper
+	 */
+	public Jackson2ResourceReader(ObjectMapper mapper) {
+		this.mapper = mapper == null ? DEFAULT_MAPPER : mapper;
+	}
+
+	/**
+	 * Configures the JSON document's key to lookup the type to instantiate the object. Defaults to
+	 * {@link Jackson2ResourceReader#DEFAULT_TYPE_KEY}.
+	 * 
+	 * @param typeKey
+	 */
+	public void setTypeKey(String typeKey) {
+		this.typeKey = typeKey;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.init.ResourceReader#readFrom(org.springframework.core.io.Resource, java.lang.ClassLoader)
+	 */
+	public Object readFrom(Resource resource, ClassLoader classLoader) throws Exception {
+
+		InputStream stream = resource.getInputStream();
+		JsonNode node = mapper.reader(JsonNode.class).readTree(stream);
+
+		if (node.isArray()) {
+
+			Iterator<JsonNode> elements = node.elements();
+			List<Object> result = new ArrayList<Object>();
+
+			while (elements.hasNext()) {
+				JsonNode element = elements.next();
+				result.add(readSingle(element, classLoader));
+			}
+
+			return result;
+		}
+
+		return readSingle(node, classLoader);
+	}
+
+	/**
+	 * Reads the given {@link JsonNode} into an instance of the type encoded in it using the configured type key.
+	 * 
+	 * @param node must not be {@literal null}.
+	 * @param classLoader
+	 * @return
+	 */
+	private Object readSingle(JsonNode node, ClassLoader classLoader) throws IOException {
+
+		JsonNode typeNode = node.findValue(typeKey);
+		String typeName = typeNode == null ? null : typeNode.asText();
+
+		Class<?> type = ClassUtils.resolveClassName(typeName, classLoader);
+
+		return mapper.reader(type).readValue(node);
+	}
+}