SWS-586 - specify custom TransformerFactory in org.springframework.xml.transform.TransformerObjectSupport

Author: poutsma

xml/src/main/java/org/springframework/xml/transform/TransformerObjectSupport.java

@@ -22,10 +22,13 @@
 import javax.xml.transform.TransformerConfigurationException;
 import javax.xml.transform.TransformerException;
 import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.TransformerFactoryConfigurationError;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.util.Assert;
+
 /**
  * Convenient base class for objects that use a <code>Transformer</code>. Subclasses can call {@link
  * #createTransformer()} or {@link #transform(Source, Result)}. This should be done per thread (i.e. per incoming
@@ -40,10 +43,48 @@ public abstract class TransformerObjectSupport {
     /** Logger available to subclasses. */
     protected final Log logger = LogFactory.getLog(getClass());
 
-    private static TransformerFactory transformerFactory = TransformerFactory.newInstance();
+    private TransformerFactory transformerFactory;
+
+    private Class transformerFactoryClass;
+
+    /**
+     * Specify the {@code TransformerFactory} class to use.
+     */
+    public void setTransformerFactoryClass(Class transformerFactoryClass) {
+        Assert.isAssignable(TransformerFactory.class, transformerFactoryClass);
+        this.transformerFactoryClass = transformerFactoryClass;
+    }
+
+    /**
+     * Instantiate a new TransformerFactory.
+     * <p>The default implementation simply calls {@link TransformerFactory#newInstance()}.
+     * If a {@link #setTransformerFactoryClass "transformerFactoryClass"} has been specified explicitly,
+     * the default constructor of the specified class will be called instead.
+     * <p>Can be overridden in subclasses.
+     * @param transformerFactoryClass the specified factory class (if any)
+     * @return the new TransactionFactory instance
+     * @see #setTransformerFactoryClass
+     * @see #getTransformerFactory()
+     */
+    protected TransformerFactory newTransformerFactory(Class transformerFactoryClass) {
+        if (transformerFactoryClass != null) {
+            try {
+                return (TransformerFactory) transformerFactoryClass.newInstance();
+            }
+            catch (Exception ex) {
+                throw new TransformerFactoryConfigurationError(ex, "Could not instantiate TransformerFactory");
+            }
+        }
+        else {
+            return TransformerFactory.newInstance();
+        }
+    }
 
     /** Returns the <code>TransformerFactory</code>. */
     protected TransformerFactory getTransformerFactory() {
+        if (transformerFactory == null) {
+            transformerFactory = newTransformerFactory(transformerFactoryClass);
+        }
         return transformerFactory;
     }
 
@@ -55,7 +96,7 @@ protected TransformerFactory getTransformerFactory() {
      *          if thrown by JAXP methods
      */
     protected final Transformer createTransformer() throws TransformerConfigurationException {
-        return transformerFactory.newTransformer();
+        return getTransformerFactory().newTransformer();
     }
 
     /**