1 files changed, 78 insertions, 0 deletions
diff --git a/src/main/java/com/p4square/ccbapi/CCBXmlBinder.java b/src/main/java/com/p4square/ccbapi/CCBXmlBinder.java
new file mode 100644
index 0000000..f347643
--- /dev/null
+++ b/src/main/java/com/p4square/ccbapi/CCBXmlBinder.java
@@ -0,0 +1,78 @@
+package com.p4square.ccbapi;
+
+import com.p4square.ccbapi.exception.CCBParseException;
+import com.p4square.ccbapi.model.CCBAPIResponse;
+
+import javax.xml.XMLConstants;
+import javax.xml.bind.JAXBContext;
+import javax.xml.bind.JAXBException;
+import javax.xml.bind.Unmarshaller;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamConstants;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.XMLStreamReader;
+import java.io.InputStream;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * CCBXmlBinder is used to bind XML responses to CCBAPIResponse implementations.
+ *
+ * This class is thread-safe.
+ */
+public class CCBXmlBinder {
+    private final XMLInputFactory xmlInputFactory;
+    private final ConcurrentHashMap<Class<? extends CCBAPIResponse>, JAXBContext> jaxbContextCache;
+
+    public CCBXmlBinder() {
+        xmlInputFactory = XMLInputFactory.newFactory();
+        jaxbContextCache = new ConcurrentHashMap<>();
+    }
+
+    public <T extends CCBAPIResponse> T bindResponseXML(InputStream response, Class<T> responseClass)
+            throws CCBParseException {
+        try {
+            final XMLStreamReader xmlReader = xmlInputFactory.createXMLStreamReader(response);
+            final JAXBContext jaxbContext = getJAXBContext(responseClass);
+            final Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
+
+            // Skip ahead to the response entity.
+            while (xmlReader.hasNext()) {
+                xmlReader.next();
+                if (xmlReader.isStartElement() && "response".equalsIgnoreCase(xmlReader.getLocalName())) {
+                    // Parse and return the response.
+                    // If the response cannot be parsed a JAXBException will be thrown.
+                    return (T) unmarshaller.unmarshal(xmlReader);
+                }
+            }
+
+            // If we reach this point then the response did not contain a response element.
+            throw new CCBParseException("Response did not contain a response element.");
+
+        } catch (XMLStreamException | JAXBException e) {
+            throw new CCBParseException("Failed to parse response.", e);
+        }
+    }
+
+    /**
+     * Find or create the JAXBContext for a CCBAPIResponse implementation.
+     *
+     * @param responseClass The response implementation class.
+     * @return a JAXBContext which can be used to unmarshell the responseClass.
+     */
+    private JAXBContext getJAXBContext(Class<? extends CCBAPIResponse> responseClass) {
+        if (!jaxbContextCache.containsKey(responseClass)) {
+            synchronized (jaxbContextCache) {
+                // Check again to be sure.
+                if (!jaxbContextCache.containsKey(responseClass)) {
+                    try {
+                        final JAXBContext jaxbContext = JAXBContext.newInstance(responseClass);
+                        jaxbContextCache.put(responseClass, jaxbContext);
+                    } catch (JAXBException e) {
+                        throw new AssertionError("Could not construct JAXBContext for " + responseClass.getName(), e);
+                    }
+                }
+            }
+        }
+        return jaxbContextCache.get(responseClass);
+    }
+}