DATACMNS-885 - Added XML support for incoming projections based on XMLBeam.

Added an XML flavor of the support added in previous commits based on XML Beam [0].

[0] http://www.xmlbeam.org.

src/main/java/org/springframework/data/web/XmlBeamHttpMessageConverter.java

@@ -0,0 +1,112 @@
+/*
+ * Copyright 2015-2016 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.web;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.http.HttpInputMessage;
+import org.springframework.http.HttpOutputMessage;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.HttpMessageNotReadableException;
+import org.springframework.http.converter.HttpMessageNotWritableException;
+import org.springframework.util.ConcurrentReferenceHashMap;
+import org.xmlbeam.ProjectionFactory;
+import org.xmlbeam.XBProjector;
+
+/**
+ * A read-only {@link HttpMessageConverter} to create XMLBeam-based projection instances for interfaces.
+ * 
+ * @author Oliver Gierke
+ * @see http://www.xmlbeam.org
+ * @soundtrack Dr. Kobayashi Maru & The Mothership Connection - Anthem (EPisode One)
+ */
+public class XmlBeamHttpMessageConverter implements HttpMessageConverter<Object> {
+
+	private final ProjectionFactory projectionFactory;
+	private final Map<Class<?>, Boolean> supportedTypesCache = new ConcurrentReferenceHashMap<Class<?>, Boolean>();
+
+	/**
+	 * Creates a new {@link XmlBeamHttpMessageConverter}.
+	 */
+	public XmlBeamHttpMessageConverter() {
+		this.projectionFactory = new XBProjector();
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.http.converter.HttpMessageConverter#canRead(java.lang.Class, org.springframework.http.MediaType)
+	 */
+	@Override
+	public boolean canRead(Class<?> type, MediaType mediaType) {
+
+		Class<?> rawType = ResolvableType.forType(type).getRawClass();
+
+		Boolean result = supportedTypesCache.get(rawType);
+
+		if (result != null) {
+			return result;
+		}
+
+		result = mediaType.isCompatibleWith(MediaType.APPLICATION_XML) && rawType.isInterface()
+				&& AnnotationUtils.findAnnotation(rawType, ProjectedPayload.class) != null;
+
+		supportedTypesCache.put(rawType, result);
+
+		return result;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.http.converter.HttpMessageConverter#canWrite(java.lang.Class, org.springframework.http.MediaType)
+	 */
+	@Override
+	public boolean canWrite(Class<?> clazz, MediaType mediaType) {
+		return false;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.http.converter.HttpMessageConverter#getSupportedMediaTypes()
+	 */
+	@Override
+	public List<MediaType> getSupportedMediaTypes() {
+		return Collections.singletonList(MediaType.APPLICATION_XML);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.http.converter.HttpMessageConverter#read(java.lang.Class, org.springframework.http.HttpInputMessage)
+	 */
+	@Override
+	public Object read(Class<? extends Object> clazz, HttpInputMessage inputMessage)
+			throws IOException, HttpMessageNotReadableException {
+		return projectionFactory.io().stream(inputMessage.getBody()).read(clazz);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.http.converter.HttpMessageConverter#write(java.lang.Object, org.springframework.http.MediaType, org.springframework.http.HttpOutputMessage)
+	 */
+	@Override
+	public void write(Object t, MediaType contentType, HttpOutputMessage outputMessage)
+			throws IOException, HttpMessageNotWritableException {}
+}

src/main/java/org/springframework/data/web/config/SpringDataWebConfiguration.java

@@ -31,6 +31,7 @@ import org.springframework.data.web.PageableHandlerMethodArgumentResolver;
 import org.springframework.data.web.ProjectingJackson2HttpMessageConverter;
 import org.springframework.data.web.ProxyingHandlerMethodArgumentResolver;
 import org.springframework.data.web.SortHandlerMethodArgumentResolver;
+import org.springframework.data.web.XmlBeamHttpMessageConverter;
 import org.springframework.format.FormatterRegistry;
 import org.springframework.format.support.FormattingConversionService;
 import org.springframework.http.converter.HttpMessageConverter;
@@ -125,5 +126,9 @@ public class SpringDataWebConfiguration extends WebMvcConfigurerAdapter {
 
 			converters.add(0, converter);
 		}
+
+		if (ClassUtils.isPresent("org.xmlbeam.XBProjector", context.getClassLoader())) {
+			converters.add(0, new XmlBeamHttpMessageConverter());
+		}
 	}
 }