Added XmlPayloadMarshallingTransformer delegating to a Spring OXM Marshaller and/or Unmarshaller (INT-109).

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/transformer/XmlPayloadMarshallingTransformer.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2002-2008 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.integration.xml.transformer;
+
+import java.io.IOException;
+
+import javax.xml.transform.Result;
+import javax.xml.transform.Source;
+import javax.xml.transform.dom.DOMResult;
+
+import org.w3c.dom.Document;
+
+import org.springframework.integration.message.Message;
+import org.springframework.integration.message.MessageHandlingException;
+import org.springframework.integration.transformer.MessageTransformer;
+import org.springframework.oxm.Marshaller;
+import org.springframework.oxm.Unmarshaller;
+import org.springframework.xml.transform.StringResult;
+
+/**
+ * An implementation of {@link MessageTransformer} that delegates to an
+ * OXM {@link Marshaller} and/or {@link Unmarshaller}.
+ * 
+ * @author Mark Fisher
+ */
+public class XmlPayloadMarshallingTransformer implements MessageTransformer {
+
+	private final Marshaller marshaller;
+
+	private final Unmarshaller unmarshaller;
+
+
+	public XmlPayloadMarshallingTransformer(Marshaller marshaller, Unmarshaller unmarshaller) {
+		this.marshaller = marshaller;
+		this.unmarshaller = unmarshaller;
+	}
+
+	public XmlPayloadMarshallingTransformer(Marshaller marshaller) {
+		this.marshaller = marshaller;
+		this.unmarshaller = (marshaller != null && marshaller instanceof Unmarshaller) ?
+				(Unmarshaller) marshaller : null;
+	}
+
+
+	@SuppressWarnings("unchecked")
+	public void transform(Message message) {
+		Object transformedPayload = null;
+		Object originalPayload = message.getPayload();
+		if (originalPayload instanceof Source) {
+			if (this.unmarshaller == null) {
+				throw new MessageHandlingException(message, "no Unmarshaller available");
+			}
+			try {
+				transformedPayload = this.unmarshaller.unmarshal((Source) originalPayload);
+			}
+			catch (IOException e) {
+				throw new MessageHandlingException(message, "failed to unmarshal payload", e);
+			}
+		}
+		else {
+			if (this.marshaller == null) {
+				throw new MessageHandlingException(message, "no Marshaller available");
+			}
+			Result result = this.createResult(originalPayload);
+			if (result == null) {
+				throw new MessageHandlingException(message, "Unable to marshal payload; expected ["
+					 + String.class.getName() + "] or [" + Document.class.getName() + "] but received ["
+					 + originalPayload.getClass().getName() + "].");
+			}
+			try {
+				this.marshaller.marshal(originalPayload, result);
+				transformedPayload = result;
+			}
+			catch (IOException e) {
+				throw new MessageHandlingException(message, "failed to marshal payload", e);
+			}
+		}
+		if (transformedPayload == null) {
+			throw new MessageHandlingException(message, "failed to transform payload");
+		}
+		message.setPayload(transformedPayload);
+	}
+
+	protected Result createResult(Object objectToMarshal) {
+		if (objectToMarshal instanceof String) {
+			return new StringResult();
+		}
+		if (objectToMarshal instanceof Document) {
+			return new DOMResult();
+		}
+		return null;
+	}
+
+}

org.springframework.integration.xml/src/test/java/org/springframework/integration/xml/transformer/XmlPayloadMarshallingTransformerTests.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2002-2008 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.integration.xml.transformer;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+
+import javax.xml.transform.Result;
+import javax.xml.transform.Source;
+
+import org.junit.Test;
+
+import org.springframework.integration.message.GenericMessage;
+import org.springframework.integration.message.Message;
+import org.springframework.integration.message.StringMessage;
+import org.springframework.oxm.Marshaller;
+import org.springframework.oxm.Unmarshaller;
+import org.springframework.oxm.XmlMappingException;
+import org.springframework.xml.transform.StringResult;
+import org.springframework.xml.transform.StringSource;
+
+/**
+ * @author Mark Fisher
+ */
+public class XmlPayloadMarshallingTransformerTests {
+
+	@Test
+	public void testStringToStringResult() {
+		Marshaller marshaller = new TestMarshaller();
+		XmlPayloadMarshallingTransformer transformer = new XmlPayloadMarshallingTransformer(marshaller);
+		Message<?> message = new StringMessage("world");
+		transformer.transform(message);
+		assertEquals(StringResult.class, message.getPayload().getClass());
+		assertEquals("hello world", message.getPayload().toString());
+	}
+
+	@Test
+	public void testStringSourceToString() {
+		Marshaller marshaller = new TestMarshaller();
+		XmlPayloadMarshallingTransformer transformer = new XmlPayloadMarshallingTransformer(marshaller);
+		Message<?> message = new GenericMessage<StringSource>(new StringSource("world"));
+		transformer.transform(message);
+		assertEquals(String.class, message.getPayload().getClass());
+		assertEquals("hello world", message.getPayload().toString());
+	}
+
+
+	private static class TestMarshaller implements Marshaller, Unmarshaller {
+
+		@SuppressWarnings("unchecked")
+		public boolean supports(Class clazz) {
+			return true;
+		}
+
+		public void marshal(Object originalPayload, Result result) throws XmlMappingException, IOException {
+			if (result instanceof StringResult) {
+				((StringResult) result).getWriter().write("hello " + originalPayload);
+			}
+		}
+
+		public Object unmarshal(Source source) throws XmlMappingException, IOException {
+			if (source instanceof StringSource) {
+				char[] chars = new char[8];
+				((StringSource) source).getReader().read(chars);
+				return "hello " + new String(chars).trim();
+			}
+			return null;
+		}
+	}
+
+}